FitSugar

Don't Take It Sitting Down

FitSugar — Thu, 09 Oct 2008 10:00:00 -0700

We all know that being sedentary doesn't burn up the calories like going for a run, but sitting down all day may be worse for you than you think. New research on the simple act of sitting indicates that our fat burning enzymes actually turn off if we are seated for extended periods of time. Long bouts of sitting can also slow down your metabolism and lower your beneficial HDL cholesterol. It seems like we just weren't meant to sit at a desk all day long.

These three reasons alone should be enough motivation to help you move about throughout your day. Here are a few ideas for getting up and out of your chair. Try to walk at lunch or for your coffee breaks. Don't send an e-mail, get up and talk to your co-worker face to face. Stand while you talk on the phone, or pace and talk if you're able. Why not throw in a few exercises while you're at your desk? Here are ways you can work it, while at work too.

Source

Exercise, Weight Loss, and the Fat Burning Zone

FitSugar — Tue, 17 Nov 2009 05:50:01 -0800

Much has been made of late about exercise and its relation to weight loss. There was the Time cover story The Myth About Weight Loss and a recent article on the topic in the New York Times, which recommended working out in the fat burning zone.

You see the phrase on all types of cardio machines: the fat burning zone, aka the "weight loss zone," means working out at a lower intensity to burn fat as fuel. But these workouts also burn considerably fewer calories. I was confused about how we should all be spending our cardio time, so I took my questions to exercise physiologist Jason Karp, who also happens to be an avid runner.

When I asked him if we should all be scaling our workouts back and aiming for the fat burning zone, Karp explained that it's not the type of fuel your body is burning, but the overall calories that count. "It doesn't matter if you're using fat or carbohydrates. In order to lose fat from your waistline you don't have to be using fat as fuel during workout," he said. He offered up the example of sprinters; they don't train in the fat burning zone, but they're mighty trim in the torso. Losing weight comes down to math - you want to be in a calorie deficit to shed pounds and body fat. Higher intensity exercise puts you at a higher burn rate. To burn the most calories in a cardio workout, skip past the fat burning zone and work out with more intensity. To really burn up calories, Karp recommends intervals. To learn why, read more.

Essentially, interval workouts give you the most bang for your sweat buck. Karp explains that with "intense exercise you're pushing your body more out of homeostasis," that is, the equilibrium of energy the body prefers to maintain. During the few hours after an interval workout, the body must go through a recovery period, and a lot needs to happen to return to the body to pre-exercise levels. "You've got to drop the heart rate, synthesize glycogen for the muscles, remove lactate from muscle and take it to the liver," says Karp. All these actions require energy, which raises the metabolic rate for many hours after exercising. Thirty minutes of exercise at a low intensity doesn't place nearly as much stress on the body as intervals, so you burn fewer calories both during and after the workout.

Before you hit the track and start running intervals, Karp recommends building a strong cardiovascular fitness base and working with a trainer for guidance. Even if you're not ready for sprints, play with your speed during your next cardio session. Slow and steady might win the race, but intervals will burn more calories.

Source: Flickr User pistoldrawn

You Asked: Working Out Buzzed?

FitSugar — Thu, 08 Oct 2009 09:00:06 -0700

Hey Fit,
I had post-work appetizers and drinks with a girlfriend last night, and as we departed she said she was heading to the gym. Granted, we each had two light beers over maybe an hour and 20 minutes, but it surprised me that she'd go work out after a couple drinks. She said she doesn't do it all the time, but if she's not feeling too tipsy it actually helps her kind of zone out and get into her workout, and by the time she's finished any possible buzz is gone. Is this healthy to do?
- mamasitamalita

There are days when we try to pack it all in: work, catching up with friends, working out. With the recent news that folks who drink regularly tend to exercise more, I suspect this dilemma is increasingly common. To see what I have to say on the matter, keep reading.

Avoid Crash Diets: Healthy Weight-Loss Tips

FitSugar — Thu, 10 Sep 2009 03:00:55 -0700

I read a very sad and unfortunate tale of an English bride-to-be's death after crash dieting. After eating only 530 calories a day for 11 weeks, the 34-year-old collapsed. Having weighed 244 pounds at the start of the controversial LighterLife diet, Samantha Clowe had lost 42 pounds when she collapsed and died of heart failure. Her family and fiancé are in my thoughts, and in light of this tragedy, I would like to review five rules for healthy and sustainable weight loss.

To lose weight you need to be in a caloric deficit, meaning you consume fewer calories than you are expending. Think of it like this: calories coming in need to be fewer than calories going out. It really is pretty simple.
To lose one pound a week you need to be in a caloric deficit of 3,500 calories. The best way to do this is to combine eating fewer calories and burning more calories - that means exercise! Cardio is great for burning calories. See these posts for ideas to freshen up your cardio routine.

Learn the other three tips when you continue reading.

Weight control and diet

FitSugar — Wed, 08 Oct 2008 17:34:58 -0700

HEALTH GUIDE REFERENCE FROM A.D.A.M

Highlights

Cancer and Weight Control:

Cancer prevention guidelines from the American Cancer Society stress the importance of maintaining a healthy weight throughout life. A healthy weight is even more important than eating specific healthy foods, when it comes to cancer prevention.

Drug Warning:

The US Food and Drug Administration (FDA) is warning consumers not to buy a product known as the "Brazilian diet pill." This product is labeled as a dietary supplement, but contains several chemicals found in powerful prescription drugs. The products are also known as Emagrece Sim and Herbathin dietary supplements.

New Over-the-Counter Medication:

In February 2007, the FDA approved the first over-the-counter (OTC) weight-loss drug. Orlistat, previously available only by prescription as Xenical, will be available OTC at half its prescription strength. It will be sold under the name alli. Those eager to use the new pill should consider its cost and modest benefits compared with its side effects, most commonly oily diarrhea. This pill, which prevents fat absorption from food, also increases the risk of not absorbing important nutrients from food while using it. The FDA recommends taking a daily multivitamin supplement when using alli.

Research News:

A small study in Norway found that a diet low in fat and high in carbohydrates ("carbs") increases symptoms of psychological distress, such as depression and anger. The study compared three different diets with varying amounts of fat and carbohydrates.
A study released in March 2007 found that obesity in young girls results in early puberty -- as early as age 9.

Effects of Obesity on the Body:

Obesity is associated with certain problems related to infertility, such as uterine fibroids or menstrual irregularities. In men, obesity can contribute to reduced testosterone levels.
People who are obese are at higher risk for carpal tunnel syndrome and other problems involving nerves in their wrists and hands.
The Pickwickian syndrome, named for an overweight character in a Dickens novel, occurs in severe obesity when lack of oxygen produces intense and chronic sleepiness and, eventually, heart failure.

Introduction

A stable weight depends on a good balance between the energy you get from food and the energy you use. You use energy during the day in three ways:

As energy expended during rest (basal metabolism)
As energy used to break down food (thermogenesis)
As energy used during physical activity

Basal metabolism accounts for about two-thirds of spent energy. Your body generally uses this energy to keep your body temperature steady and keep the muscles of your heart and intestine working. Thermogenesis accounts for about 10% of spent energy.

When a person consumes more calories than the energy they use, the body stores the extra calories in fat cells. Fat cells function as energy reservoirs. They enlarge or shrink depending on how people use energy. If people do not balance energy input and output by eating right and exercising, fat can build up. This can lead to weight gain.

When energy input is equal to energy output, there is no expansion of fat cells (lipocytes) to accommodate excess. It is only when more calories are taken in than used that the extra fat is stored in the lipocytes and the person begins to accumulate fat.

Obesity is determined by measuring body fat, not just body weight. People might be over the weight limit for normal standards, but if they are very muscular with low body fat, they are not obese. Others might be normal or underweight, but still have excessive body fat. The following measurements and factors are used to determine whether or not a person is overweight to a degree that threatens their health:

Body mass index (BMI) (a measure of body fat)
Waist circumference (size around the waist)
Waist-hip ratio
Skin fold measurement (anthropometry)
The presence or absence of other disease risk factors (e.g., smoking, high blood pressure, unhealthy cholesterol levels, diabetes, relatives with heart disease)

A person's disease risk factors plus BMI may be the most important components in determining health risks with weight.

The Body Mass Index (BMI). The current standard measurement for obesity is the body mass index (BMI). In general, a BMI of 25 - 29.9 means you are overweight. Obesity is a BMI of 30 and above. Obesity is then classified into three categories:

Class 1: BMI of 30 - 34.9
Class II: BMI 35 - 39.9
Class III: BMI of 40 and greater

These guidelines are very important for people at risk for diabetes, heart disease, or certain cancers. It is also used to determine treatment approaches such as when surgery may be appropriate. The higher the BMI, the greater the risk for significant health problems.

Calculating Body Mass Index (BMI). One's body mass index (BMI) is calculated by multiplying a person's weight in pounds by 703, dividing by the height in inches, and then dividing that number by the height in inches. The steps are as follows:

Multiply one's weight in pounds by 703
Divide that answer by height in inches
Divide that answer again by height in inches

For example, a woman who weighs 150 pounds and is five feet eight inches (or 68 inches) tall has a BMI of 22.8.

Waist Circumference and Waist-Hip Ratio. The extent of abdominal fat can also be used in assessing risk of disease. Some studies suggest that:

Women whose waistlines are over 31.5 inches and men whose waists measure over 37 inches should watch their weight.
A waist size greater than 35 inches in women and 40 inches in men is associated with a higher risk for heart disease, diabetes, and impaired functioning.

Evidence strongly suggests that more body fat around the abdomen and hips (the apple-shape) is a more consistent predictor of heart problems and health risks than BMI.

The distribution of fat can be evaluated by dividing waist size by hip size. For example, a woman with a 30-inch waist and 40-inch hip circumference would have a ratio of 0.75; one with a 41-inch waist and 39-inch hips would have a ratio of 1.05. The lower the ratio the better. The risk of heart disease rises sharply for women with ratios above 0.8 and for men with ratios above 1.0.

Click the icon to see a depiction of the waist-to-hip ratio.

Anthropometry. Anthropometry is the measurement of skin fold thickness in different areas, particularly around the triceps, shoulder blades, and hips. This measurement is useful in determining how much weight is due to muscle or fat.

Biological and Medical Causes

Obesity results when a person consumes more calories than they need for the energy they use. Several different factors may influence weight gain.

About 90% of people who lose weight through dieting gain every pound back regardless of their weight-loss method.

Some evidence suggests that every person has an inherited weight. This range varies by only about 10% either up or down from some set point. For instance, a man whose "genetically-determined" weight is 200 pounds would tend to swing from 180 - 220 pounds. He would be unlikely to lose or gain more than this.

Genetic factors may play some part in 70 - 80% of obesity cases.

Appetite is determined by processes that occur both in the brain and gastrointestinal tract. Eating patterns are controlled by areas in the hypothalamus and pituitary glands (in the brain). The body produces a number of molecules that increases or decreases appetite. In some cases, the following factors may produce imbalances in this process:

Insulin. Insulin is a hormone that helps change blood sugar (glucose) into energy. During digestion, carbohydrates from our diet break down into different types of sugar molecules (including glucose). Proteins from our diet break down into smaller molecules called amino acids. Immediately after eating, blood glucose levels rise. This triggers the release of insulin, which pours into the bloodstream. Insulin pushes the glucose and amino acids into cells and muscles. Insulin and other hormones determine which nutrients will be burned for energy or stored for future use. The inability to use insulin efficiently (insulin resistance) has been associated with both obesity and diabetes.
Leptin. Leptin is a hormone that is released by fat cells. A number of scientists think this hormone may also be released by cells in the stomach. Leptin appears to play an important role in insulin resistance and fat storage in the body, but its role in obesity is unclear. The most likely scenario is that leptin levels rise as the cells store more fat. This increase in leptin levels decreases appetite. Falling levels of leptin make you feel hungry. In people who have genetically lower levels of leptin, however, the brain may be tricked into thinking that it is always starving because there is no leptin to decrease appetite. This can lead to weight gain.
Resistin. Resistin is a hormone produced by fat cells. It makes the body resistant to insulin activity. Some experts believe it may help explain the role of obesity in diabetes type 2.
Intestinal Chemicals. Ghrelin is a chemical produced in the stomach. It appears to be important in triggering the desire to eat. Peptide YY3–36 (PYY) is a substance secreted in the intestines after a meal. The level of PYY is proportionate to the number of calories a person eats. PYY tells the brain that you feel full. Deficiencies in ghrelin and PYY may contribute to some cases of obesity. Researchers are hoping that blocking ghrelin or infusing PYY may be possible treatments for obesity.
Other Chemicals. Many brain chemicals are being studied for their role in appetite stimulation and weight gain. Among them are neuropeptide Y, melanocortins, agouti-related protein, and melanocyte stimulating hormone. Pain-relieving chemicals called endorphins may be critical in reducing appetite and regulating energy use. Cholecystokinin, a hormone released in the upper intestine that stimulates digestive juices, may work to control meal size.

Insulin is a hormone produced by the pancreas that is necessary for cells to be able to use blood sugar.

Genetics may directly contribute to severe obesity in people with family histories of the problem. Genetic factors such as slow metabolisms may also make people more likely to be overweight. At least seven genetic mutations have been associated with specific and uncommon cases of severe obesity. Some are outlined below.

HOB1 (human obesity 1) is a gene that is linked to a high BMI in women.
Leptin gene variants have been linked to leptin deficiencies and obesity.
Melanocortin-4 receptor is a gene that helps turn off the urge to eat. It may not work properly in those with a family history of obesity.
Researchers have also identified a mutation in a gene for a protein called proopiomelanocortin, which results in a syndrome of obesity, red hair, and deficiencies in stress hormones.
A protein called agouti-related protein increases hunger. About 5% of severely obese people have mutations that over-respond to agouti-related protein.

Genetics also determine the number of fat cells a person has. Some people are simply born with more. It should be noted that even when genetic factors are present, a person can still control their diet.

The Thrifty Gene. Some experts think the existence of a so-called "thrifty" gene regulates changes in hormone levels, to accommodate seasonal changes. Theoretically, it works in the following manner:

In certain populations, hormones are released during seasons when food supplies have traditionally been low. This leads to insulin resistance and increased fat storage.
The process is reversed in seasons when food is readily available.
Because modern industrialization has made high carbohydrate and fatty foods available all year long, the gene no longer serves a useful function. Fat, originally stored for famine situations, is not used.

This theory could explain why the previously nomadic Native American tribes who now have Western dietary habits have such high rates of Type 2 diabetes and obesity. In the past, the traditional low-fat, high-fiber foods tribe members ate may have protected them from obesity and type 2 diabetes. Today, these tribes' diet consists of more Western foods, which are higher in fat. Furthermore, these foods are readily available year-round, and many members of the tribe are sedentary. The result is a very high incidence of Type 2 diabetes and obesity. Although genetic abnormalities may make it harder or easier to lose weight, the occurrence of obesity has dramatically increased over the past two decades, and genes cannot have changed within that short amount of time. Our ability to use the food that we eat evolved so that our body could conserve energy and store fat during times of famine. Most cases of obesity now occur in people with normal body function who live in industrialized nations, where there is more than enough food.

A number of medical conditions may contribute to being overweight, but rarely are they a primary cause of obesity.

Hypothyroidism is sometimes associated with weight gain. But, patients with an underactive thyroid generally show only a moderate weight increase of five to 10 pounds.
Very rare genetic disorders, including Froehlich's syndrome in boys, Laurence-Moon-Biedl, and the Prader-Willi syndromes, cause obesity.
Abnormalities or injury to the hypothalamus gland can cause hypothalamic obesity.
Cushing's disease is a rare condition caused by high levels of steroid hormones. It results in obesity, a moon-shaped face, and muscle wasting.
Obesity is also linked to polycystic ovarian syndrome, a hormonal disorder in women.

Click the icon to see an image of polycystic ovaries.

Some prescription medications contribute to weight gain, usually by increasing appetite. Such drugs include the following:

Corticosteroids
Female hormone treatments, including some oral birth control pills (effect is usually temporary), and certain progestins (such as Megestrol) used to treat cancer
Antidepressants and anti-psychotic drugs, including lithium and valproate
Insulin and insulin-stimulating drugs used to treat diabetes often lead to weight gain, a particularly unfortunate conflict of interest for obese individuals with type 2 diabetes

You should not stop taking any medications without your doctor's knowledge.

Cultural and Emotional Causes

Enough food is produced in the US to supply 3,800 calories every day to each man, woman, and child in the country, far more than the average person needs to sustain life. In a 2002 study, participants carefully recorded everything they ate and drank, and all activities and psychological factors surrounding the eating events. The people who gained weight ate more and their portions were larger than those who did not. This may be an obvious conclusion, but the public press often plays up biologic factors involved with obesity and overlooks the simple notion that Americans eat too much and exercise too little.

Obesity is dramatically increasing not only in American children and adults, but also in every country that has adopted similar cultural habits. The World Health Organization now considers obesity to be a global epidemic and a public health problem as more nations become "Westernized." In spite of the proven health risks of obesity, the government, insurance companies, and the medical profession do not spend nearly enough money to balance the commercial and cultural pressures that are producing millions of overweight people.

In 2007, the Robert Wood Johnson Foundation sounded a positive note with the announcement of a $500 million initiative, aimed at “reversing the childhood obesity epidemic by 2015.” The money will be used for research, education, and activities that promote healthy eating among America’s children.

Perhaps the primary reason for the dramatic rise in obesity is the sedentary (inactive) lives led by most Americans, including children and young people. In a 2003 study comparing modern life to the past, researchers found that labor saving devices had reduced a person's energy use by 111 calories a day -- adding up to an extra 11 pounds a year. Half the difference in energy use was due to less walking. At the same time, according to the U.S. Centers for Disease Control and Prevention, between 1970 and 2000 the typical American man increased his caloric intake by 168 calories a day (good for 17 pounds a year) while the average woman added 335 calories a day.

Regular television watching has been singled as the most hazardous pastime. According to a major 2003 study, for every 2 hours a person spends in front of the TV each day, the risk for obesity increases by 23% and for type 2 diabetes by 14%. In the study, TV watching produced the lowest metabolic rates compared to sewing, playing board games, reading, writing, and driving a car. Just the act of watching TV encourages unhealthy snacks and eating patterns. In addition, the advertising on the television complicates the problem by promoting fast foods, cereal, and snack products that are high in salt, fats, and carbohydrates. Even worse, much of these advertisements are directed at children -- the most vulnerable group.

People are not only eating more food than they did 20 years ago, they are also replacing home cooking with packaged foods, fast food, and dining out. This behavior, according to studies, places people at higher risk for obesity. Fast foods may be more harmful than restaurant cooking. These foods tend to be served in larger portions. They generally contain more calories and unhealthy fats, and less nutritious ingredients, than homemade or restaurant meals. Snack foods and sweet beverages, including juice and soft drinks, are specific problems that add to the increasing rates of obesity. Frequent small, healthy meals (instead of two or three large daily meals) have been associated with lower weights.

People react differently to stress. Some overeat and gain weight and others stop eating and lose weight. People who gain weight in response to stress often overeat foods high in sugar, fats, and salt. A 2003 study on rats suggested that stress hormones increase the pleasure of eating such so-called "comfort foods." Furthermore, the study supported previous research showing that stress-related eating was connected to the unhealthy accumulation of abdominal fat.

Risk Factors

Where you live plays a role in your risk for obesity. Simply living in the United States makes a person more susceptible to obesity. The prevalence of obesity in America has risen dramatically over the past few years and continues to increase.

According to the latest figures available, 32.2% of American adults (aged 20 and older) are obese (BMI over 30) -- up from about 23% in the early 1990s.
The number of Americans aged 20 - 74 who were overweight also increased -- from about 44.8% in 1960 to 65.2% in 2002.
The rate of extreme obesity (BMI > 40) increased from 0.8% in 1960 to 4.9% in 2002.
Obesity has increased in every state, in both men and women, across all age groups, and in every ethnic group, although some groups may face slightly higher risks than others.

Fat tends to settle in certain regions, depending on gender. Women gain fat predominantly in the stomach, hips and thighs, while men tend to gain fat in the belly and waist.

Risk by Age. People of any age are at risk for obesity. More children and adolescents are overweight in America than ever before. Gaining some weight is inevitable with age and adding about 10 pounds to a normal base weight over time is not harmful. The current weight gain in American adults over 50, however, is significant. By age 55, the average American has added nearly 40 pounds of fat during the course of adulthood. This condition is made worse by the fact that muscle and bone mass decrease with age.

Risk by Gender. In men, BMI tends to increase until age 50 and then it levels off. In women, weight tends to increase until age 70 before it plateaus. A 2000 study found that there are three high-risk periods for weight gain in women.

The first is at the onset of menstruation, particularly if it is early. In fact, a study released in March 2007 found that obesity in young girls results in early puberty -- as early as age 9. This, in turn, increases the risk for more weight gain as girls enter puberty.
The second is after pregnancy, with higher risk for women who are already overweight.
Finally, many women gain weight after menopause.

These findings are significant because they may allow women to target high-risk times, and consequently prevent unnecessary weight gain.

Risk by Economic Group. Obesity is more prevalent in lower economic groups. One 2002 study reported that women who reported that they did not have enough food were more likely to be overweight than those who said they had sufficient food. Researchers discovered that the low-income women tended to have fewer fruits and vegetables but were actually taking in more calories a day than higher-income women. However, obesity is increasing in young adults with college education as well as in other groups.

Ethnic Groups. Among ethnic groups in general, African-American women are more overweight than Caucasian women but African-American men are less obese than Caucasian men. (Currently, 80% of African-American women are overweight.) Hispanic men and women tend to weigh more than Caucasians.

US Regions. Regionally, the prevalence of obesity is lowest in the Western states and highest in the South.

A number of dietary habits put people at risk for becoming overweight:

Night-Eating Syndrome. Night-eating syndrome is defined as having no appetite in the morning, insomnia, and consuming more than half of daily food intake after 6:00 PM. It is associated with obesity and is difficult to treat. Stress reduction and relaxation techniques may be helpful.
Binge Eating and Eating Disorders. About 30% of people who are obese are binge eaters who typically consume 5,000 - 15,000 calories in one sitting. To be diagnosed as a binge eater, a person has to binge at least twice a week for 6 months. Many experts believe that binge-eating carbohydrates causes an increase in a natural opiate leading to dependence on carbohydrates. Therefore, this condition should be treated as an addiction. Other eating disorders are bulimia and anorexia. Bulimia is binge eating followed by purging in order to lose weight. Anorexia nervosa is a mental illness in which the person refuses to maintain weight at the normal level. The patient with anorexia has a terrible fear of getting fat, and an abnormal perception of what his or her body looks like. Both conditions pose risks for serious medical problems, and anorexia nervosa can be life-threatening. A combined approach using behavioral therapy and antidepressants may help these individuals. [See In-Depth Report #49: Eating disorders.]
Restrained Eating. Some people, mostly middle-aged women who have normal weight, have a pattern referred to as restrained eating. This pattern requires a high level of conscious control and usually maintains a lower weight. However, such restraint places these individuals at higher risk for loss of control and subsequent overeating.
Infrequent Eating. There is some evidence to suggest that eating small frequent meals uses more calories than infrequent large meals. It should be strongly noted, however, that packaged snack foods add calories and some do not produce a feeling of being full, so that people simply eat more than they should.

Anyone with Sedentary Lifestyles. Office workers, drivers, and anyone whose lifestyle involves sitting for long periods are at higher risk for obesity.

Ex-Smokers. The trend toward weight increase has followed the trend for quitting smoking. Nicotine increases the metabolic rate, and quitting, even without eating more, can cause weight gain, which may be considerable. It is important to note that weight control is not a valid reason to smoke. People in previous centuries did not smoke cigarettes, nor were they usually obese.

Shift-Workers. A recent study found that individuals who work late shifts (between 4 p.m. and 8 a.m.) tend to eat more and take longer naps than day workers and are more likely to gain excess weight.

People with Disabilities. Obesity rates are higher than average in people with physical or mental disabilities. Those with disabilities in the lower part of the body, such as the legs, are at highest risk.

Overweight in children and adolescents is rising at an alarming rate. In 2004, 19% of young children aged 6 - 11 were overweight, an increase of 8% from 1994. Among children aged 25, 13.9% were overweight in 2004, up from 7.2% 10 years earlier.

Definition of Overweight in Children

Children and adolescents are considered to be overweight if their BMI is above 95% of the children in their age and sex categories. Ethnic variations, timing of growth spurts, and higher normal fat levels around puberty can affect these measurements.

Causes and Risk Factors for Overweight in Children

Lifestyle Factors. Without educational or parental guidance, children are extremely vulnerable to the intense cultural pressures that are largely responsible for the obesity epidemic. The following are some specific problems created by the culture:

Excessive television watching plays a critical role in obesity in children. Not only is it a sedentary activity, but television also offers innumerable temptations with its advertisements for fast foods, sugar cereals, and unhealthy snacks. In one study obesity rates were lowest in children who watched television 1 hour or less a day and highest in those who watched 4 or more hours.
Sugar, particularly from soda, other sweetened beverages, and fruit juice, may be the major contributor to childhood obesity. One study reported that drinking soda regularly increases a child's risk for obesity by 60%. The average American adolescent consumes 15 - 20 extra teaspoons of sugar a day just from soda and sugary drinks. (Juice, while better than soda, is still filled with sugar.)
Less physical exercise and greater sedentary activities play another significant role in obesity in children. A high level of physical activity -- not just using up energy -- is important for weight control in young people. Unfortunately, according to one study, the annual distance walked by children has fallen by nearly 30% since 1972, partially because more parents are driving their children to school out of fear of abduction, molestation, and traffic accidents. Schools are also offering fewer opportunities for daily physical activities than in the past.

Neither the media nor the educational system has strong well-financed programs that encourage healthy alternatives, including exercise and healthy foods.

Family History. Parental obesity more than doubles the risk that a young child, whether thin or overweight, will become obese as an adult. In older children and teenagers, obesity in parents starts to count less as a predictor for body weight than their own weight. The risk for obesity may be due to environmental or genetic factors, or both.

Ethnic and Socioeconomic Factors. As in adult populations, children from lower socioeconomic groups and minority populations are at higher risk for obesity. For example, among young Mexican Americans and African-Americans, there has been an increase in overweight prevalence of about 13% to over 23%.

Factors Surrounding Birth. The following factors surrounding birth are associated with a child's weight:

Low birth weight is a risk factor for later obesity and diabetes. One theory is that humans have a "thrifty gene" that produces metabolic changes in infants with low birth weight. Such changes affect insulin and fat accumulation, in order to produce a "catch-up" weight in these young children as quickly as possible. This rapid weight gain in infancy increases the risk for obesity in children and young adults.
In a study of African-American children, having an overweight pregnant mother increased the risk for later weight gain, but low birth weight did not.

Although some small studies have reported protection against obesity from breastfeeding, evidence is weak. In a 2003 study, for example, children who were breast fed for 3 - 5 months had a lower risk for obesity, but prolonged breastfeeding had no effect. Nevertheless, given the healthful effects of breast feeding and the possibility that it may have even a slight impact on childhood obesity, it is highly recommended.

Biological Effect of Childhood Overweight on Adult Weight

Achieving a healthy weight becomes more difficult as children get older. The odds of obesity persisting into adulthood ranges from 20% in 4 year olds to 80% in teenagers. One reason for the persistence is biological. The fat cells change in number or mass depending on a person's age:

Fat cells themselves multiply during two growth periods: early childhood and adolescence. Overeating during those times increases the number of fat cells. Some people are also just born with more fat cells.
After adolescence, fat cells tend to increase in mass rather than quantity, so that adults who overeat and gain weight tend to have larger fat cells, not more of them. This growth in mass may be responsible for the greater risk of persistent obesity among teenagers compared to small children who are overweight. Losing weight after adolescence reduces the size of the fat cells but not their number, so weight loss becomes much more difficult.

Health Consequences of Childhood Overweight

Children and adolescents who are overweight have poorer health than other children. Studies are reporting unhealthy cholesterol levels and high blood pressure in overweight children and adolescents. Of great concern is the dramatic increase in type 2 diabetes in young people, which is largely due to the increase in overweight children. Overweight in children is also linked to asthma, gallbladder problems, sleep apnea, and liver abnormalities. Overweight girls are more likely to enter puberty early, according to a new study, and subsequently be at higher risk for breast cancer.

It is not clear yet how many of these childhood problems persist in people who achieve normal weight as adults. Staying overweight into adulthood certainly carries health risks.

Managing Overweight Children

Childhood obesity is best treated by a non-drug, multidisciplinary approach including diet, behavior modification, and exercise. Evidence suggests that reducing calories by only 200 - 260 per day would prevent weight gain in most overweight children. Here some tips for children who are overweight:

Limit (or avoid, if possible) take out, fast foods, high-sugar snacks, commercial packaged snacks, soda, and sugar-sweetened beverages (including too much juice).
Let children snack but make sure the snacks are healthy. Eating small frequent healthy meals (instead of two or three large ones) has been associated with being thinner and having a better cholesterol profile.
Let children choose their own food portions. One study indicated that children naturally ate 25% less when they chose their own portion size. When they were given larger portions their bite sizes were larger and they ate more.
Do not criticize a child for being overweight. It does not help and such attitudes could put children at risk for eating disorders, which are equal or even greater dangers to their health.
Limit television, video games, and computer use to a few hours a week. This can contribute significantly to weight control, regardless of diet and physical activity.
For young children, try the traffic-light diet. Food is designated with stoplight colors depending on their high caloric content: Green for go (low calories); yellow for "eat with caution" (medium calories); red for "stop" (high calories).
Try a low glycemic index diet. This may be as beneficial, and possibly more, than a standard reduced-fat diet in overweight children. Such a diet focuses on certain carbohydrates (for example, dried beans and soy), which raise blood sugar more slowly than other types of carbohydrates. This diet is sometimes used in diabetes, and as a dietary approach in overweight adults. [See In-Depth Report #42: Diabetes diet.]

Click the icon to see an image about TV watching.

Click the icon to see an image of childhood overweight.

Complications

General Adverse Effects of Obesity. Obesity, defined as a BMI of 30 or over, accounts for nearly 300,000 deaths in the U.S. each year. It is associated with more chronic health problems than smoking, heavy drinking, or poverty. Furthermore, given the current increase in obesity, it will surpass smoking as the most important preventable cause of death in America.

Some studies indicate the following health risks by body mass:

The lowest risks for heart disease, diabetes, and some cancers are in people with BMI values of 21 - 25.
The risks increase slightly when BMI values are between 25 - 27.
The risks are significant in BMIs between 27 - 30.
The same risks are dramatic at BMIs over 30.

Anyone with chronic health problems such as heart or lung disease, stroke, or arthritis, should be concerned about extra weight. This same concern also applies to people with known risk factors for such conditions.

Metabolic Changes. As fat stores increase, the fat cells themselves enlarge and produce chemicals that increase the risk for several diseases. Such diseases may include diabetes, high blood pressure, gallbladder disease, and some cancers.
Increased Mass. The increased body weight itself causes problems that result in injury and diseases, including osteoarthritis and sleep apnea.
Harmful Fat Cell Types. Weight concentrated around the abdomen and in the upper part of the body (the apple shape) poses a higher health risk than fat that settles around the hips and flank (the pear shape). Fat cells in the upper part of the body appear to have different qualities from those found in the lower parts. In fact, studies suggest a higher risk for diabetes in people with the "apple shape" and lower risk in those who are "pear shaped."

Weight gain in the area of and above the waist (apple type) is more dangerous than weight gained around the hips and flank area (pear type). Fat cells in the upper body have different qualities than those found in hips and thighs.

General Adverse Effects of Being Overweight (Not Obese). It is still not clear if being overweight (a BMI of 25 - 29.9) hurts healthy people with no risk factors for serious illnesses.

According to one 2001 study, just being overweight increased the risk for developing diabetes, gallstones, hypertension, heart disease, stroke, and colon cancer. The risk rose according to how much the individuals were overweight. In any case, adults who are overweight in middle age face a poor quality of life as they age, with the quality declining the greater the weight. One study suggested, however, that being over 65 and overweight (but not obese) is not associated with higher mortality rates.

Some experts argue, in fact, that in anyone who is not severely obese, it is the unhealthy diet and sedentary lifestyle that causes harm -- not weight per se. In support of this argument, a British study found that overweight fit individuals had half the death rate of unfit trim individuals.

Being somewhat overweight may also have some benefits under specific circumstances:

In older women, some excess fat may produce extra estrogen that helps slow down bone loss, and insulates bones from fall-related injuries. It should be strongly noted, however, that when older overweight women lose weight they report less pain, improved vitality, and improved physical function. The same positive effect of overweight does not appear to hold in older men.
Conditioned athletes may have high BMIs because of very dense muscle tissue. Being fit in general may protect many overweight people.
Some evidence suggests that Caucasians have the lowest mortality with BMIs of 24.3 - 24.7 while African-Americans are better off in the range of 26.8 - 27.1.
Children may have higher normal fat levels during growth spurts and around puberty.

Individuals with a BMI of at least 30 have a 10 - 50% increased rate of death from all causes, compared with individuals with a BMI of 20 - 25. Mortality rates from many causes are higher in obese people, but heart disease is the primary cause of death. People who are obese have almost three times the risk for heart disease as people with normal weights. Being physically unfit adds to the risk.

Weight concentrated around the abdomen and in the upper part of the body (apple shape) is particularly associated with insulin resistance and diabetes, heart disease, high blood pressure, stroke, and unhealthy cholesterol levels. Fat that settles in a pear shape around the hips and lower body appears to have a lower association with these conditions.

Obesity poses many dangers to the heart and circulatory system.

Damage in the Blood Vessels. As people age, changes in body fat (particularly increasing abdominal fat) seem to cause stiffness in the aorta, the major blood vessel leading from the heart. Studies are finding higher levels of a factor called C-reactive protein (CRP) in people with obesity and abdominal fat. CRP is now considered to be a marker for inflammation and damage in the arteries. (Losing weight reduces CRP levels.)

High Blood Pressure. High blood pressure is the health problem most commonly associated with obesity, and the greater the weight, the greater the risk. High blood pressure carries serious risks of stroke, heart attack, and heart failure. The link between obesity and high blood pressure is complex, and may be a combination of genetic, population, and biological factors. Many studies have reported that modest weight loss is beneficial for reducing existing high blood pressure. [See In-Depth Report #14: High blood pressure.]

Heart Failure. An important 2002 study reported that obesity might account for 11% of heart failure cases in men and 14% in women. This link existed independently of other risk factors, such as high blood pressure, sleep apnea, and diabetes, which are also associated with obesity. The biologic mechanisms involved in obesity that lead specifically to heart failure are not clear. [See In-Depth Report #13: Heart failure.]

Unhealthy Cholesterol Levels and Lipid Levels. The effect of obesity on cholesterol levels is complex. Although obesity does not appear to be strongly associated with overall cholesterol levels, among obese individuals triglyceride levels (the major form of fat storage in the body) are usually high, while HDL levels (the "good" cholesterol) tend to be low. Both conditions are risk factors for heart disease. [See In-Depth Report #23: Cholesterol.]

Click the icon to see an image of coronary artery disease.

Stroke. Obesity is also associated with a higher risk for stroke. [See In-Depth Report #45: Stroke.]

Type 2 Diabetes and Insulin Resistance. Most people with type 2 diabetes are obese and, in fact, studies strongly suggest that weight loss may be the key in controlling the current epidemic of type 2 diabetes. The common factor appears to be insulin resistance. Insulin is a critical hormone in the use of sugar. In type 2 diabetes, different factors cause the body to become insulin resistant -- that is, the body can no longer respond properly to insulin. This has the effect of increasing sugar levels in the blood, the hallmark of diabetes. Both obesity and insulin resistance, at different phases, are marked by high levels of certain chemicals. It is not known yet if the higher levels are simply a product of obesity, or play some role in causing diabetes.

Insulin resistance is also associated with high blood pressure and abnormalities in blood clotting. Some research indicates that obesity, in fact, is the one common element linking insulin resistance, diabetes type 2, and high blood pressure. [See In-Depth Report #60: Diabetes - type 2.]

Metabolic Syndrome. Metabolic syndrome (also called syndrome X) is a pre-diabetic condition that is significantly associated with heart disease and higher mortality rates from all causes. The syndrome consists of obesity marked by abdominal fat, unhealthy cholesterol levels, high blood pressure, and insulin resistance. A 2002 study estimated that nearly a quarter of the U.S. population now has this condition. Even worse, according to a 2003 study, nearly a million American teenagers have this syndrome. A combination of weight loss and exercise is an effective treatment for this syndrome.

The American Cancer Society released new cancer prevention guidelines in September 2006. The guidelines stress the importance of keeping a healthy weight throughout life. The Society indicates that healthy weight is even more important than eating specific healthy foods, when it comes to cancer prevention.

Obesity has been associated with a higher risk for cancer in general and specific cancers in particular. Studies have also suggested that restricting calories reduces the risk for cancer. Some experts believe that effective weight control for children and adults could reduce cancer rates by 30 - 40%. One way obesity may increase the risk for cancer is its association with high levels of hormones called growth factors, which can trigger rapid cell production leading to cancer.

Uterine Cancers. The risk of uterine cancer in obese women appears to be two or three times higher than in thinner women.

Prostate Cancer. New studies from 2005 and 2006 report that obesity is associated with an increase in prostate cancer mortality, although not with the risk for less aggressive forms of prostate cancer.

Click the icon to see an image of prostate cancer.

Breast Cancer. Studies are mixed on the association between obesity and breast cancer. A number of studies have linked obesity to breast cancer in postmenopausal women, particularly in women who begin to gain weight after age 18.

Click the icon to see an illustrated series detailing a breast cancer surgery (mastectomy).

Gallbladder Cancer. Obese women are at higher risk for gallbladder cancer.

Gastrointestinal Cancers. A number of cancers in the gastrointestinal tract have been associated with obesity:

Cancer of the esophagus may be due to a higher incidence of gastroesophageal reflux disorder (heartburn) in people who are overweight.
Colon cancer has been linked to increased body mass in both men and women.
Pancreatic cancer and obesity have been weakly linked, with one study reporting a lower risk in overweight people who are physically active.

Click the icon to see an illustrated series detailing a colon cancer surgery.

Muscles and Bones

Obesity places stress on bones and muscles. Studies report that the incidence of osteoarthritis is significantly increased in people who are overweight. People who are obese are also at higher risk for carpal tunnel syndrome and other problems involving nerves in their wrists and hands. It should be noted that some weight may be protective against osteoporosis (loss of bone thickness).

Obesity increases the risk for the following mouth and eye disorders:

Gum disease
Cataracts
Maculopathy, an eye disease related to aging

Infertility. Abnormal amounts of body fat, either 10 - 15% too high or too low, can contribute to infertility in women. Obesity is specially related to certain infertility problems, such as uterine fibroids or menstrual irregularities. In men, obesity can contribute to reduced testosterone levels.

Effect on Pregnancy. Obesity has many dangerous effects on pregnancy. These include high blood pressure, gestational diabetes (diabetes, usually temporary, that occurs during pregnancy), urinary tract infections, blood clots, prolonged labor, and higher fetal death rate in late stages of pregnancy. Obesity is also associated with increased rates of cesarean delivery. Infants of women who are obese are also at higher risk for neural tube birth defects, which affect the brain or spine. Folic acid supplements, ordinarily effective in preventing these conditions, may not be as protective in overweight women.

Obesity is thought to be a risk factor for symptoms of adult-onset asthma. Though there is evidence that obesity causes wheezing and shortness of breath, it does not appear to be strongly associated with the disease mechanisms in the lungs that cause true asthma.

Obesity also puts people at risk for hypoxia, a condition in which there is not enough oxygen to meet the body's needs. Obese people need to work harder to breathe. They tend to have breathing muscles and lungs that do not work as well as those in thinner people.

The Pickwickian syndrome, named for an overweight character in a Dickens novel, occurs in severe obesity when lack of oxygen produces intense and chronic sleepiness and, eventually, heart failure.

Nonalcoholic Fatty Liver Disease. People with obesity, particularly if they also have type 2 diabetes, are at higher risk for a condition called nonalcoholic fatty liver disease, also called nonalcoholic steatohepatitis (NASH). This condition causes liver damage that is similar to liver injury seen in alcoholism. In some cases, it can be very serious and require liver transplantation. It occurs in about half of people with diabetes, and 20 - 50% of obese people, depending on how severe their obesity is. NASH can also occur in overweight children.

Gallstones. The incidence of gallstones is significantly higher in obese women and men. The risk for stone formation is also high if a person loses weight too quickly. In people on ultra-low calorie diets, gallstones may be prevented by taking ursodeoxycholic acid (Actigall).

Click the icon to see an image of gallstones.

People who are obese and nap tend to fall asleep faster and sleep longer during the day. At night, however, it takes them longer to fall asleep, and they sleep less than people with normal weights. In an apparent vicious circle, studies have suggested that obesity not only interferes with sleep but that sleep problems may actually contribute to obesity.

Sleep Apnea. Obesity, particularly the apple shape, is strongly associated with sleep apnea, which occurs when the upper throat relaxes and collapses from time to time during sleep. This collapse temporarily blocks the passage of air. Sleep apnea is increasingly being viewed as a potentially serious health problem, which may lead to complications such as heart disease and stroke. Some studies suggest that among overweight people, those who have sleep apnea have a greater risk of heart disease than those without it. In one study, the more obese a person with sleep apnea was, the higher the pressure on the airway, and therefore the greater the obstruction of the airway. Obstructive sleep apnea may also add to obesity, however, as sleepy people tend to be sedentary. Some studies indicate that treating sleep apnea may help people lose abdominal fat.

Narcolepsy. A small European study found a link between narcolepsy (a sleep disorder characterized by excessive daytime sleepiness with frequent daily sleep attacks) and high BMI.

Depression. A number of studies have reported an association between depression and obesity, particularly in obese women. There may be a number of factors to explain the link. In some cases of atypical depression, people overeat and may gain weight. Overweight people may also become depressed because of social problems and a poor self-image. In these cases, depression usually disappears when people lose weight.

There is evidence, however, that obesity itself may impair levels of tryptophan -- a chemical needed to make serotonin, a brain chemical associated with mental well-being. In one study, even after people lost weight, tryptophan levels were lower than normal.

There does not appear to be any association between depression and obesity in men.

Social Problems. One long-term study reported that overweight young women completed fewer years of school, were 20% less likely to be married, and had 10% higher rates of household poverty than their thinner peer. Obese young men were also less likely to be married, and their incomes were lower than their thinner peers. Nevertheless, studies consistently show that overweight males (both boys and men) are not as severely emotionally affected as females of any age. Women and girls tend to blame themselves for being heavy, while males tend to blame being overweight on outside factors.

Weight Loss and Maintenance

Even modest weight loss can reduce the risk factors for heart disease and diabetes. The simplest (but still difficult) approach to weight loss is reducing calories and exercising at least 150 minutes a week. Behavioral and mental changes in eating habits, physical activity, and attitudes about food and weight are also essential to weight management. For people who are very overweight and cannot lose weight through lifestyle changes, a number of effective weight-loss medications are available. For those with severe obesity, surgical procedures are proving to be very beneficial.

Some Tips for Losing Weight. The following are some general suggestions for dieters:

Start with realistic goals. Diet failure is extremely common, and the odds of significant weight loss are low, particularly in people with the highest weights. People who are able to restrict calories, engage in an exercise program, and get help in making behavioral changes can expect to lose between 5 - 10% of their current body weight. That is generally all that is needed to achieve meaningful health changes. Certainly, the distorted image of a super-thin female shape should not be anyone's goal.
Maintain a regular exercise program, assuming you have no health problems that will stop you. Choose a program that you enjoy. Check with your doctor about any health considerations. [See In-Depth Report #29: Exercise.]
Do not use hunger pangs as cues to eat. A stomach that has been stretched by large meals will continue to signal hunger for large amounts of food until its size reduces over time with smaller meals.
Be honest about how much you eat and start by recording all calories in writing. Studies suggest that when many people report their own calories intake they significantly underestimate their consumption of high-calorie and over-estimate the low-calorie foods. People who do not carefully note everything they eat tend to take in too many calories when they believe they are dieting.
Observe weekend eating. People tend to eat more on the weekends. If it is difficult to monitor all meals during the week, it be may be useful to at least track eating habits during the weekends.
Once the pounds are lost, do your best to keep the healthier weight. Make daily, even hourly, conscious decisions about eating and exercising activities. Such thinking, in many cases, can become automatic and not painful.
Don't give up, even after repeated weight loss failures. Most studies indicate that yo-yo dieting or weight cycling have no bad psychological or physical effects. Repeated dieting also does not harm the body's ability to burn calories efficiently.
Weight loss, in any case, should not be the only or even the primary goal for people concerned about their health. The success of weight loss efforts should be evaluated according to improvements in disease risk factors or symptoms, and by the adoption of healthy lifestyle habits, not just by the number of pounds lost.


Lifestyle	Reduce rate of eating. Keep food records. Eliminate environmental triggers to eating. Identify high-risk situations for overeating. Separate eating from other activities.
Exercise	Face up to emotional barriers to exercise. Understand the link between exercise and weight control. Establish reasonable exercise goals. Develop a plan for regular activity. Add increased activity into daily lifestyle.
Attitudes	Develop reasonable weight-loss goals. Avoid "all or none" thinking. Focus attention away from the scale and toward behavior. Uncouple weight from self-esteem. If you "fall off the wagon," take steps to ensure the situation does not repeat (recover from lapses with constructive action).
Relationships	Understand the key role of social support to health. Identify supportive others. Match personal style to support-seeking activities. Be specific in making support requests. Be assertive but reinforcing in drawing help from others.
Nutrition	Resist the temptation of popular fad diets. Eat with your health in mind; do not concentrate on what should be "off-limits." Eat with moderation in mind. Maximize fiber. Develop a tailored plan.
From Brownell KD. The LEARN Program for Weight Control. 7th ed. Dallas, Tex: American Health Publishing Company; 1998.

Weight Management

There are many approaches to dieting and many claims for great success with various fad diets. To date, although many diets achieve effective immediate weight loss, none has emerged as an effective tool for maintaining healthy weight. The only definite recommendation that can be made about any diet plan is to be sure it includes an exercise program, assuming there are no health problems to forbid it.

The original food pyramid, with four food groups, has been replaced with an updated food guide called "My Pyramid." This illustrates the relative proportions of different foods that make up a nutritious, well-balanced diet and includes exercise.

Calorie restriction has been the cornerstone of obesity treatment. The standard dietary recommendations for losing weight are the following:

As a rough rule of thumb, one pound of fat equals about 3,500 calories. A person could lose a pound a week by reducing daily caloric intake by about 500 calories a day. Naturally, the more severe the daily calorie restriction, the faster the weight loss. Very-low calorie diets have also been associated with better success, but extreme diets can have some serious health consequences.
To determine your daily calories requirements, multiply the number of pounds of ideal weight by 12 - 15 calories. The number of calories per pound depends on gender, age, and activity levels. For instance, a 50-year old woman who wants to maintain a weight of 135 pounds and is mildly active might require only 12 calories per pound (1,620 calories a day). A 25-year old female athlete who wants to maintain the same weight might require 25 calories per pound 2,025 (calories a day).
Fat intake should be no more than 30% of total calories. Most fats should be in the form of monounsaturated fats (such as olive oil). Saturated fats (found in animal products) should be avoided.

Extreme diets of less than 1,100 calories carry health risks. They are also often followed by bingeing or overeating, and a return to the obese state. Such diets often do not have enough vitamins and minerals, which must then be taken as supplements. Most of the initial weight loss is in fluids. Later, fat is lost, but so is muscle, which can account for more than 30% of the weight loss. No one should be on severe diets for longer than 16 weeks, or fast for more than 2 or 3 days. Severe dieting has unpleasant side effects including fatigue, intolerance to cold, hair loss, gallstone formation, and menstrual irregularities. There have been rare reports of death from heart arrhythmias when liquid formulas did not have sufficient nutrients. Pregnant women who excessively diet during the first trimester put their unborn children at risk for birth defects. Of note, those whose diets include a high intake of fluids and much reduced protein and sodium are at risk for hyponatremia, which can cause fatigue, confusion, dizziness, and in extreme cases, coma and death.

This dietary approach requires counting only grams of fat with the goal of achieving 30% or fewer calories from fat. One gram of fat contains nine calories, while one gram of carbohydrates or protein has only four calories. Fat in your diet converts more readily to fat in the body, compared with carbohydrates or proteins. Simply switching to low-fat or skimmed dairy products may be enough for some people.

There are possible drawbacks to this approach:

Some people who reduce their fat intake may not get enough basic nutrients, including vitamins A and E, folic acid, calcium, iron, and zinc. People on low-fat diets should eat a wide variety of foods and take a multivitamin supplement, if appropriate. Calcium deficiencies may be particularly harmful in women at risk for osteoporosis.
Many people start eating foods with too many carbohydrates, believing that they are not adding calories. No one should use a low-fat diet as an excuse for eating too many carbohydrates, particularly starchy foods and sugar. A high-calorie diet from any source will add pounds.
A small study in Norway found that a diet low in fat and high in carbohydrates ("carbs") increases symptoms of psychological distress, such as depression and anger. The study compared three different diets that had varying amounts of fat and carbohydrates in each. The diets contained the same amount of calories, but differed in the percentage and type of fat. People on the low-fat, high-carbohydrate diet reported more anger and depression compared with the other two diets.
Replacing fatty foods, such as cakes, cookies, and chips, with their commercial "low-fat" counterparts does not constitute a low-fat diet. These foods generally contain more sugar and hence calories, not to mention other ingredients, which have virtually no nutritional value. In fact, a 2002 study suggested that increasing sugar may, over time, reduce levels of HDL ("good") cholesterol.
Very low-fat diets may increase the risk for stroke from hemorrhage in the brain.

Some fat in a diet is essential. It should come from plant oils and fish, however, and not from animal products or hardened oils, such as margarine. Trans-fatty acids, found in hardened oils, are actually more of a risk factor for obesity than saturated fats from animal products, although both should be avoided.

Fiber and Complex Carbohydrates. In all cases, complex carbohydrates found in whole grains and vegetables are preferred over those found in starch-heavy foods, such as pastas, white-flour products, and potatoes. Fiber is an important component of many complex carbohydrates. Fiber is almost always found only in plants, particularly vegetables, fruits, whole grains, nuts, and legumes (beans and peas). One exception is chitosan, a dietary fiber made from shellfish skeletons. Fiber cannot be digested but passes through the intestines, drawing water with it, and is eliminated as part of feces content. The following are specific advantages from high-fiber diets (up to 55 grams a day):

Insoluble fiber (found in wheat bran, whole grains, seeds, nuts, and fruit and vegetable peels) has been associated with weight loss. Studies also suggest that diets rich in fiber from whole grains reduce the risk for type 2 diabetes.
Soluble fiber (found in dried beans, oat bran, barley, apples, citrus fruits, and potatoes) has important benefits for the heart, particularly for achieving healthy cholesterol levels and possibly benefiting blood pressure as well. Simply adding breakfast cereal to a diet appears to reduce cholesterol levels. People who increase their levels of soluble fiber should also increase water and fluid intake.

High-protein, low carbohydrate diets, such as the Atkins and South Beach diets, have been touted as effective ways to produce short-term weight loss. Because of their emphasis on fats and proteins, many experts are concerned about long-term health problems. A report in the March 2006 Lancet linked the Atkins diet to life-threatening complications that caused the death of one woman. The 40-year-old woman had a deadly buildup of acids called ketones in her blood, a condition called ketoacidosis. Ketoacidosis can cause coma and death. Ketones are a known by-product of high protein, low carbohydrate diets. At low levels they can cause nausea, lightheadedness, and bad breath.

The long-term effects of these diets are still unknown. For example, the Atkins diet restricts some vegetables and most fruits, which are known to protect against serious diseases such as heart problems and cancer. The diet may also cause too much calcium to build up in the urine. This can increase the risk for kidney stones and osteoporosis. In addition, high-protein intake, particularly from meat, can be harmful in people with kidney problems. Individuals at risk for kidney stones, or those who have other kidney problems, should not go on high-protein diets without talking to their doctor first. Unfortunately, many people with diabetes are at risk of kidney problems, which could reverse any possible benefits a high-protein diet may bring them. Eating a lot of meat has also been associated with certain common cancers, notably prostate and colon cancers. A 2002 study suggested that such diets during pregnancy may increase the risk for high blood pressure in the child.

Still, significant studies say that such diets improve cholesterol and blood sugar levels. Studies in 2002 and 2003 have indicated that these diets lower blood glucose levels, which can be important in people who are diabetic. The diets also reduce triglyceride levels (unhealthy fat molecules) and increases HDL (" good") cholesterol levels. High triglyceride and low HDL levels are important risk factors for heart disease, and are common in people with type 2 diabetes. Studies are mixed on whether this type of diet reduces overall cholesterol or LDL ("bad") cholesterol levels.

Experts that promote the low carbohydrate approach argue that heart problems from obesity are due to insulin disturbances from sugar imbalances. Therefore, they believe that restricting carbohydrates is the best approach for obesity -- especially for overweight people with diabetes. More research is needed, however, to determine the long-term impact of such diets on health.

High-protein, low-carbohydrate diets include Atkins, Protein Power, Sugar Busters, and Dr. Stillman. The Atkins diet is one of the most popular and has a four-phase program:

Induction. For the first 2 weeks, individuals consume no more than 20 grams of carbohydrates a day. The diet consists of pure protein and fats. There is no fruit, bread, grains, starchy vegetables, or dairy products other than cheese, cream, or butter. This phase is not suitable for children, pregnant women, or anyone with kidney disease.
On-going Weight Loss. After the first phase, individuals continue to lose weight while they increase carbohydrate levels by five grams each day.
Premaintenance. When individuals get close to their weight goal, they add another 10 grams of carbohydrates per day as long as they do not begin to gain weight. Weight loss is very slow at this time, but the individual is now getting used to maintenance.
Maintenance. Lifetime maintenance is usually between 40 and 100 grams of carbohydrates a day, depending on steady weight level.

Anyone who chooses this diet should prefer fish or soy products to meat as protein sources. Fish may reduce leptin, a hormone associated with fat storage and heart diseases, and would be the best protein source. People on this diet should also choose monounsaturated fats (as in olive oil) over saturated fats or trans-fatty acids fat. Patients often need supplements, at least a multivitamin and possibly calcium, chromium, omega-3 fatty acids (found in fish oil), and other supplements.

The South Beach and Zone diets encourage healthy fats. They also allow certain carbohydrates. For example the Zone uses healthy carbohydrates (vegetables and dried beans) and unsaturated fats. The South Beach diet uses carbohydrates that have a lower impact on blood sugar levels. This is called a low-glycemic index. Low-glycemic foods include barley, dried bean and peas, milk, strawberries, and apples. High-glycemic foods include refined grains, white bread, white potatoes, and bananas and other tropical fruits. The glycemic index was developed for use in diabetes -- not for weight loss. Nevertheless, there is some evidence that foods with low glycemic indexes may produce a feeling of fullness and so discourage further eating. As with any high-protein diets, people at risk for kidney stones, or those who have other kidney problems, should avoid these plans.

Replacing fats and sugars with substitutes may help many people who have trouble maintaining weight. In fact, in one 2003 study, people with type 2 diabetes used the artificial sweetener sucralose and a beta-glucan fat substitute (derived from oats) as part of a low-calorie diet. At the end of the 4 weeks, they achieved better weight, glucose control, and HDL levels than those on a standard diabetic diet.

Fat Substitutes. Fat substitutes added to commercial foods or used in baking deliver some of the desirable qualities of fat, but do not add as many calories. It should be stressed that eliminating all fats from a diet can be harmful to general health.

Fat substitutes include the following:

Stanols. Stanols are plant compounds used in margarines (Benecol, Take Control). Benecol is derived from pine bark and Take Control from soybeans. Two servings a day of either brand, as part of a low-fat, diet can lower LDL and total cholesterol by impairing its absorption in the intestinal tract. Some studies have reported that the use of stanols can allow lower doses of statins (cholesterol lowering medications). Stanols do not appear to block absorption of fat-soluble nutrients or vitamins, as olestra does.
Olestra (Olean) passes through the body without leaving behind any calories from fat. Studies suggest that it improves cholesterol levels and helps people lose weight when it is used to replace a third of normal dietary fats. (Note that simply adding snacks containing olestra does not appear to have any effect on cholesterol or weight loss.) Early reports of cramps and diarrhea after eating food containing olestra have not proven to be significant. Of greater concern is the fact that even small amounts of olestra deplete the body of certain vitamins and nutrients that may help protect against serious diseases, including cancer. The FDA requires that the missing vitamins be added back to olestra products, but not other nutrients. The side health effects, if any, are unknown.
Beta-glucan is a soluble fiber found in oats and barley. Products using this substance (e.g., Nu-Trim) may reduce cholesterol and have additional health benefits.

A number of other fat-substitutes are also available. Although studies to date are not showing any significant side effects, these products' effect on weight control is uncertain, since many of the products containing them may be high in sugar.

Artificial Sweeteners. Many artificial or low-calories sweeteners are available. A 2002 study confirmed that people who consumed artificial sweeteners and reduced their sugar intake weighed less over time than those who took in similar types and amounts of drinks and food containing sugar. It should be noted that using these artificial sweeteners should not give dieters a license to increase their fat intake. Studies indicate that consuming some sugar is not a significant contributor to weight gain, as long as the total amount of calories in the diet is under control. There is some public concern about chemicals used to produce many of these sweeteners, and the side effects seen in studies using rats. Natural low-calories sweeteners are available that may be more acceptable to many people.

Saccharin (Sugar Twin, Sweet n' Low, Sucaryl, and Featherweight). Saccharin has been used for years. Some studies found that large amounts of saccharin cause bladder cancer in rats. However, the rats were fed huge amounts that do not apply to human diets. Currently there is no evidence that saccharin causes cancer in humans.
Aspartame (Nutra-Sweet, Equal, NutraTase). Aspartame has come under scrutiny because of rare reports of nervous system disorders, including headaches or dizziness, associated with its use. People with phenylketonuria (PKU), a genetic condition, should not use it. Studies have not reported any serious health dangers, but some people may be sensitive to it.
Sucralose (Splenda). Sucralose has no bitter aftertaste and works well in baking, unlike other artificial sweeteners. It is made from real sugar by replacing part of the sugar with chlorine. Some people are concerned because chlorinated molecules used in major industrial chemicals have been associated with cancer and birth defects. Over 100 studies have been conducted on sucralose over a 20-year period, with no reports of such risks.
Acesulfame-potassium (Sweet One, SwissSweet, Sunette). It has been used in the U.S. since 1988 with no reported side effects.
Neotame (Neotame). Neotame is a synthetic variation of aspartame, but was developed to avoid its side effects. The association with aspartame has raised some concerns. Studies to date have reported no effects that would cause alarm, and it appears to be safe for general consumption.
D-tagatose (Tagatose). This reduced-calorie sweetener is made from lactose, which is the sugar found in dairy products and other foods. It may be especially beneficial for people with type 2 diabetes. It may also have additional benefits that help the intestinal tract.
Alitame (Aclame) is formed from amino acids, the building blocks of proteins. It has the potential to be used in all products that contain sugar, including baked goods.
Stevioside (Stevia). This is a natural sweetener derived from a South American plant. It is available in health food stores. People with diabetes should avoid alcohol-based forms. It has not been carefully tested.

Other sugar substitutes being investigated include glycyrrhizin (derived from licorice) and dihycrochalcone (derived from citrus fruits).

Some studies have reported good success with meal replacement beverages (Slim-Fast, Sweet Success). They contain major nutrients needed for daily requirements. Each serving typically contains between 200 - 250 calories and replaces one meal. (Note: Using them for all meals reduces calories to a severe extent and can be harmful.)

One study reported that most subjects who had undergone a 12-week weight loss program and then used Ultra Slim Fast supplements as directed for maintenance kept off more than half their weight loss after more than 3 years. A quarter of the subjects were still losing weight.

Medical evidence suggests that a diet rich in magnesium could reduce a person's risk of metabolic syndrome, a cluster of problems including obesity, high blood pressure, and high cholesterol. Metabolic syndrome can lead to diabetes and heart disease. A long-term study of thousands of Americans found that the risk for metabolic syndrome decreased in those who consumed the most magnesium from meals. The findings were published in the journal Circulation.

Commercial and Non-Profit Support Programs for Weight Loss. There are many different types of weight-loss program. (This report cannot address all of the many commercial and nonprofit weight-loss programs currently available, nor can it assess their claims.)

Taking off Pounds Sensibly (TOPS), a nonprofit support organization with many local chapters, is one of the least expensive programs, costing $20 a year.

Most of the commercial programs such as Weight Watchers, Jenny Craig, and NutriSystem offer individual or group support, lifestyle changes and packaged meals. These programs tend to be expensive. There are few well-conducted studies on these programs. One 2003 study reported modest weight loss over 2 years with Weight Watchers compared to a self-help program. There were no differences in heart risk factors.

Cognitive Behavioral Approaches. Most support programs use some form of cognitive-behavioral methods to change the daily patterns associated with eating. They are very useful for preventing relapse after initial weight loss. The following is a typical approach:

The patient first records in a diary all activity related to eating patterns, including the times of day, length of meal, emotional states, companions, and, of course, the kind and amounts of food eaten. Most people -- even professional dieticians, according to one study -- tend to underreport their daily calorie intake. However, writing it down is still a good method for increasing a person's awareness of eating patterns. (One patient said that recording circumstances surrounding relapses was a particularly valuable guide for understanding the stresses leading to her own eating behaviors.)
The patient reviews the diary with a therapist or group to set realistic goals and identify patterns that the patient can change. For instance, if food is normally eaten while watching television, then the patient may be advised to eat in another room instead.
Good eating habits are reinforced by rewards. These rewards are other pleasures that substitute the high calorie consumption and sedentary activities.

Behavioral modification has been shown to be helpful particularly for people who have an overly strong response to the taste, smell, and appearance of food. It also may be useful for binge eaters.

Stress-Reduction Techniques. Stress reduction and relaxation techniques may be helpful for some people with obesity, such as those whose weight is related to night-eating syndrome. [See In-Depth Report #31: Stress.]

Changing Sedentary Habits. Making even small changes in physical activity can expend energy. For example, simply getting up to turn the TV on and off instead of using the remote, and standing (instead of sitting) while talking on the phone may help a person lose up to five pounds a year. Other suggestions include cooking one's own food (instead of eating take-out or fast food), walking to as many places as possible, using stairs instead of escalators or elevators, and gardening. Even fidgeting may be helpful in keeping pounds off, and, in one study, chewing gum increased energy expenditure.

No one should rely on such mild activities, however, for serious weight loss. Only high levels of physical activity -- not just using up energy -- help prevent obesity.

Approach to Exercise. Exercise, which replaces fat with muscle, is the critical companion for any weight control program. In a one-year study, women who regularly averaged 3.5 days (176 minutes) of exercise each week lost significantly more weight than women who did not exercise regularly. Women who exercised more than 195 minutes a week lost nearly 7% of their abdominal fat.

People who exercise are more apt to stay on a diet plan. Exercise improves psychological well-being and replaces sedentary habits that usually lead to snacking. Exercise may even act as a mild appetite suppressant. Moreover, exercise improves overall health even with modest weight loss. In support of this, a British study found that overweight fit individuals had half the death rate of unfit trim individuals.

Be aware, however, that the pounds won't melt off magically. Losing significant weight requires both intensive exercise and calorie restriction. In addition, if a person exercises but doesn't diet, any actual pounds lost may be minimal, because denser and heavier muscle mass replaces fat. Nonetheless, regardless of weight loss, a fit body will look more toned and be healthier. In addition, exercise benefits the heart even with modest weight loss.

The following are some suggestions and observations on exercise and weight loss:

The more strenuous the exercise, the better the chances for short-term and long-term success. With intense exercise, the metabolism continues to burn calories before returning to its resting level. This state of elevated metabolism can last for as little as a few minutes after light exercise to as long as several hours after prolonged or heavy exercise.
Of the standard aerobic machines, the treadmill burns the most calories. It may be particularly effective when used in short multiple bouts during the day. In fact, frequent exercise sessions as short as 10 minutes in duration (about four times a day) may be the most successful exercise program for obese people.
Resistance, or strength, training is excellent for replacing fat with muscles. It should be performed two or three times a week.
As people slim down, their initial level of physical activity becomes easier and they burn fewer calories per mile of walking or jogging. The rate of weight loss slows down, sometimes discouragingly so, after an initial dramatic head start using diet and exercise combinations. People should be aware of this phenomenon and keep adding to their daily exercise program.
As people age, they also need to exercise more to keep off the same amount of weight.
Changes in fat and muscle distribution may differ between men and women as they exercise. Men tend to lose abdominal fat (which lowers their risk for heart disease faster than reducing general body fat). Exercise, however, does not appear to have the same effect on weight distribution in women. In one interesting study, women in aerobic and strength training programs lost fat in their arms and trunk, but did not gain muscle tissue in these regions.

Warning Note. Because obesity is one of the risk factors for heart disease and diabetes, anyone who is overweight must discuss their exercise program with a doctor before starting. Sudden demanding exercise, in such cases, can be very dangerous. [See In-Depth Report #29: Exercise.]

Medications

There are several different drugs used for weight loss. Unless specifically instructed by a doctor, people should use non-drug methods for losing weight. Except under rare circumstances, pregnant or nursing women should never take diet medications of any sort, including herbal and over-the-counter remedies.

A 2001 study reported that 7% of American adults use nonprescription weight-loss products. People must be cautious when using any weight-loss medications, including over-the counter diet pills and herbal or so-called natural remedies. Buying unverified products over the Internet can be particularly dangerous.

Green tea. Perhaps the best alternative advice for people who are overweight is to drink tea. Studies have indicated that regular tea drinking is associated with lower weight, particularly in people who drink it for years. Green tea specifically has been associated with increased energy expenditure. One study reported that people who took a green tea extract (Exolise) lost weight and reduced their waist size. Better evidence is needed to confirm the results on this supplement.

Thermogenic Approach to Weight Loss. An approach to weight loss called thermogenic (also hepatothermic) therapy is based on the idea that certain natural compounds have properties that enable the liver to increase energy in the cells and stimulate the metabolism. Theoretically, the result would be fat loss. Among the natural substances used in such products are EPA-rich fish oil, sesamin, hydroxycitrate, pantethine, L-carnitine, pyruvate, aloe vera, aspartate, chromium, coenzyme Q10, green tea polyphenols, aloe vera, DHEA derivatives, cilostazol, diazoxide, and fibrate drugs.

Nearly all the current over-the-counter dietary aids contain some combination of these ingredients. There is no evidence that any of these ingredients can produce weight loss, and some may even have harmful effects.

Chromium is a common ingredient in many diet supplements (e.g., Xenadrine, Dexatrim, Acutrim Natural, Twinlab Diet Fuel). It is claimed to specifically promote fat loss, rather than lean muscle loss. Some evidence suggests that niacin-bound chromium may improve insulin sensitivity. On the negative side, animal studies have suggested that chromium may have damaging effects on genetic materials in cells. This could cause sterility.

Ephedra, Ephedrine, and Ma Huang. The FDA does not allow the sale of drugs that contain ephedrine. In May 2004, the FDA banned the sale of dietary supplements that contain ephedra (also called Ma Huang). Ephedra has been linked to serious side effects, including strokes and heart attacks.

Brazilian Diet Pill. The US Food and Drug Administration (FDA) is warning consumers not to buy a product known as the "Brazilian diet pill." This product is labeled as a dietary supplement, but contains several chemicals found in powerful prescription drugs. The products are also known as Emagrece Sim and Herbathin dietary supplements.

Conjugated Linoleic Acid (CLA). Conjugated linoleic acid is found in many dietary products (e.g., Biosculpt Liquid, Body Success, GNC Optibolic Body Answers Dietary Formula). There is no evidence that it produces weight loss. Furthermore, there is some concern that CLA might increase insulin resistance and a dangerous inflammatory response in people with obesity.

Tiratricol. Over-the-counter products containing tiratricol, a thyroid hormone, have been sold for weight loss. Such products may increase the risk for thyroid disorders, heart attack, and stroke.

Laxative Actions in Natural Substances. Many dietary herbal teas contain laxatives, which can cause gastrointestinal distress, and, if overused, may lead to chronic pain, constipation, and dependency. In rare cases, dehydration and death have occurred. Some laxative substances found in teas include senna, aloe, buckthorn, rhubarb root, cascara, and castor oil.

Guar Gum. Some fiber supplements containing guar gum have also caused obstruction of the gastrointestinal tract.

Chitosan. Chitosan, a dietary fiber from shellfish, prevents a small amount of fat from being absorbed in the intestine. Well-conducted studies, however, have not found it to be effective. Products containing it include Cheat & Lean Fat Blocker, Natrol, Chroma Slim, and Enforma. People who are allergic to shellfish should not take these supplements.

Plantain. Dietary remedies that list the ingredient plantain may contain digitalis, a powerful chemical that affects the heart. NOTE: This substance should not be confused with the harmless banana-like plant also called plantain.

Orlistat (Xenical) can help about one-third of obese patients with modest weight loss, and can assist in long-term maintenance of weight loss. It works by slowing the absorption of fat (by about 30%) in the intestine. Studies indicate that between 50 - 80% of patients can achieve weight loss of 5% or greater, depending on other lifestyle changes. However, many people regain a significant portion of this weight back within 2 years. It does not work for all patients, however. In one survey of patients who took it, 10% gained weight or did not lose any, and 43% lost less than 5%. Nevertheless, orlistat may delay or even prevent the onset or progression of diabetes and improve cholesterol levels, regardless of weight loss.

The drug can cause gastrointestinal problems and may interfere with absorption of the fat-soluble vitamins A, D, and E and other important nutrients. The most unpleasant side effect is oily leakage of feces from the anus. Restricting fats can reduce this effect. People with bowel disease should probably avoid it. In spite of these side effects, most patients are able to tolerate this agent.

In February 2007, the FDA approved an over-the-counter (OTC) version of orlistat. It will be sold under the name alli, and will be available at half the prescription strength of Xenical. Those eager to use the new pill should consider its cost and modest benefits compared with its side effects, most commonly oily diarrhea. This pill, which prevents fat absorption from food, also increases the risk of not absorbing important nutrients from food while using it. The FDA recommends taking a daily multivitamin supplement when using alli.

Sibutramine (Meridia) helps balance the brain chemicals serotonin and norepinephrine. This helps increase metabolism, causes a feeling of fullness, and increases energy levels. It may be particularly useful for binge-eaters. Studies indicate that sibutramine is effective in achieving weight loss, although the weight loss slows considerably after the first 3 months. The drug also appears to improve cholesterol and lipid (fat) levels, and may have other effects that benefit the heart.

Side effects of sibutramine are common. They include dry mouth, constipation, and insomnia. In one study, almost half the patients dropped out as a result of these side effects. There have been reports of increases in heart rate and blood pressure while taking this medication, although a 2001 study indicates that blood pressure stabilizes over time.

At this time, people who have a history of high blood pressure, stroke, heart disease, or arrhythmias should not take this drug. People taking decongestants, bronchodilators (such as for asthma), monoamine oxidase inhibitors, or serotonin reuptake inhibitors should also avoid sibutramine.

Phentermine and Other Sympathomimetics. Sympathomimetics are drugs that act like the stress hormone (and chemical messenger) norepinephrine. These medications act as stimulants in the brain. Some are approved for treating obesity, but only for short-term use. They include:

Phentermine (Ionamin, Adipex-P, Fastin)
Benzphetamine (Didrex)
Phendimetrazine (Adipost, Bontril, Melfiat, Plegine, Prelu-2, Statobex)

Phentermine is the most commonly prescribed appetite suppressant, and is less expensive than orlistat or sibutramine. Its effects are not long lasting, however. It can also raise blood pressure. In addition, phentermine is associated with depression, which is already a problem in many cases of obesity. A combination (Phen-Pro) containing phentermine and the antidepressant fluoxetine (Prozac) is being investigated to help reduce this problem. Note: Neither phentermine nor such combinations are associated with the heart problems linked to the previous phentermine combination known as Fen-Phen (phentermine and fenfluramine).

Amphetamines. The amphetamines dextroamphetamine (Dexedrine), methamphetamine (Desoxyn), and phenmetrazine (Pleudin) are powerful stimulants. They were used most often in the past but are no longer prescribed for weight loss. These drugs improve mood and produce some modest weight loss over the short term, but carry serious risks of addiction, agitation, and insomnia.

Rimonabant. Rimonabant (Accompli) belongs to a new class of drugs called selective CB1 blockers. The drug is designed to block receptors in the brain associated with the regulation of eating. Rimonabant also targets receptors in fat tissue. The Rimonabant in Obesity-Lipids (RIO-Lipids) study looked at how rimonabant affected metabolic risk factors in high-risk overweight or obese patients with blood fat disorders. The study involved more than 1,000 participants. The findings, published in the November 2005 New England Journal of Medicine, said that people who took the drug significantly reduced their body weight and size of their waist.

Earlier studies involving the drug reported that obese patients treated with 20 mg of rimonabant lost significantly more weight and inches from their waist than patients who received placebo. The drug also appeared to have beneficial effects on raising HDL ("good") cholesterol levels.

Note: Fake rimonabant has been found for sale on several web sites. Patients should be aware that this drug is still experimental, and rimonabant is not available for sale. Buying and taking counterfeit drugs can have serious health consequences. In addition, an FDA advisory panel in April 2007 rejected the drug, citing fears it may cause psychiatric problems and seizures in some patients.

Axokine. Axokine is a type of drug called a ciliary neurotrophic factor. It signals the brain to suppress one's appetite. It is proving to be effective in achieving weight loss, and also improves cholesterol, lipid, and glucose levels regardless of food intake. It could be particularly helpful for people with type 2 diabetes. Early study results found that severely obese patient who took the drug lost more weight than those who took a dummy pill (placebo). Nearly half (46%) of patients who took the drug lost at least 10 pounds, compared to 5% of those who received the placebo. Study participants tolerated the drug well. There were no reports of serious side effects.

Zonisamide. Zonisamide (Zonegran) is an anti-seizure medication that is also being investigated for weight loss. In one study, patients who took it lost more weight than those on placebo. Zonisamide increases the risk for kidney stones, which can be reduced with increased fluid intake and citrate. It has also been associated with reduced sweating and a sudden rise in body temperature, especially in hot weather. Other side effects include dizziness, forgetfulness, headache, and nausea.

Topiramate. Topiramate (Topamax) is another anti-seizure medication being investigated for weight reduction. Three clinical trials have reported that patients given topiramate lost more weight than those receiving placebo. Weight loss was sustained for up to 1 year. The drug is also being studied for binge-eating disorders associated with obesity.

Other Treatments

Surgical procedures for obesity may be appropriate for some dangerously obese people, and may reduce heart problems and many of the risks associated with obesity. These risks include high blood pressure, sleep apnea, and diabetes. In fact, some evidence suggests that surgery may provide much greater control of weight and diabetes than nonsurgical weight-loss methods. Studies are reporting significant reductions in diabetes, and the need for diabetic medications, after surgery. Other medical conditions that often improve after surgery include heartburn, arthritis, and other joint and circulation problems.

Bariatric surgeries produce weight loss through one of two approaches:

Restrictive Banding Procedures. These procedures restrict the amount of food by closing off parts of the stomach with bands.
Malabsorptive Bypass Procedures. This approach restricts the amount of food and also reduces absorption by using a bypass of parts of the intestine.

The malabsorptive procedures are more successful in achieving weight loss than the banding approach, but they carry a greater risk for nutritional deficiencies.

Most people who have bariatric surgery lose about two-thirds of excess weight within 2 years. In addition, diseases associated with obesity (such as diabetes, high blood pressure, sleep apnea, joint pain, and incontinence) often improve.

Researchers at the Mayo Clinic looked at records from patients who had the surgery between 1990 and 2003. They found that those who had bariatric surgery reduced their risk of cardiovascular events such as a heart attack much more than those who lost weight without surgery. The findings were published in the September 2005 Mayo Clinic Proceedings.

Other studies have shown that even though most patients maintain significant weight loss, the majority regain about to 10% of their weight. Patients must still develop a healthy life style and be calorie conscious after the operation. Follow-up must be life-long.

Any surgical candidate must have failed consistently in losing weight through less invasive methods. Experts recommend bariatric surgery only for the following:

Those whose BMI is above 40 (about 100 pounds overweight)
Those with BMIs of over 35 who have type 2 diabetes or serious obesity-related medical problems
Those with severe obesity that interfered with employment, normal physical activity (e.g., walking), and important relationship

About a third of people who undergo these procedures achieve normal weight, and 80% experience some weigh loss. They are less successful than the bypass procedures, but carry a lower risk of nutritional deficiencies.

Vertical Banded Gastroplasty. Vertical banded gastroplasty (VBG) was the most common restrictive procedure. It involves creating a hole through both stomach walls and sealing the edges with a staple. This narrows the stomach, similar to a funnel, and allows only small amounts of food to pass through.

Laparoscopic Gastric Banding. Laparoscopic gastric banding (the Lap-Band) usually does not require a major incision and avoids some of the major complications of gastric bypass:

It employs an adjustable silicone band that is placed around the upper part of the stomach.
A small balloon-like reservoir attached to the band under the abdominal skin contains saline, which can be added or removed to tighten or loosen the band.
The procedure restricts the amount of food a person can eat and gives the feeling of fullness.

The band is removable, if necessary. Studies to date indicate that the intestinal tract returns to normal afterward. Studies, including those done in the elderly, have reported significant weight loss and improved quality of life with the procedure.

Malabsorptive procedures produce greater weight loss than restrictive procedures. Patients generally achieve about two-thirds of their weight loss within 2 years. Furthermore, in a 2003 study, after standard bypass surgery, 83% of patients with type 2 diabetes experienced normal blood glucose levels and the rest had significant reductions.

Roux-en-Y Gastric Bypass Procedure. This is the most common and successful malabsorptive surgery in the United States. It involves creating a small stomach pouch that serves as a reservoir and restricts food intake. The pouch eventually holds up to 3 ounces of food and has a small outlet that delays emptying and causes a feeling of fullness. Then the surgeon creates a Y-shaped section in the small intestine that attaches to the pouch. This section allows food to bypass the lower stomach and upper part of the intestine. One 2003 study reported that this procedure was associated with significant weight loss, and 80% of patients with type 2 diabetes were able to reduce their medications. A more recent study, published in the March 14, 2006, issue of Archives of Surgery, found that gastric bypass surgery also helps lower the blood pressure of very obese patients.

The procedure produces greater and more sustained weight loss than banding procedures, but it is also more complicated, and carries a higher risk of nutritional deficiencies. Laparoscopy techniques, which are less invasive, are now preferred over open surgery. They achieve equally good results with fewer complications.

Biliopancreatic Diversion. This procedure is more complicated and removes portions of the stomach. The pouch that is created attaches directly to the lower part of the small intestine. It poses a higher risk for nutritional deficiencies than other procedures and is not used as often.

Click the icon to see an image of gastric bypass surgery.

General Side Effects and Complications. Side effects and complications of bariatric procedures are common, and up to 25% of patients require corrective or repeat procedures. After any of these procedures people must chew all their food carefully, and they cannot eat large amounts of food at one time. If patients do not follow these guidelines, they will experience nausea, abdominal distress, or both.

Complications from any bariatric procedure includes the following:

Vomiting: This is the most common complication, and it is most common with banding procedures.
Nutritional deficiencies: There is a strong risk of nutritional deficiencies, particularly with malabsorptive operations. This complication can lead to anemia and increase the risk of bone loss and osteoporosis. Taking enough mineral and vitamin supplements is important after bariatric surgery.
Deep-vein thrombosis: There is a significant risk for deep-vein thrombosis (blood clots in the veins).
Abdominal hernia: This is another common complication. Newer, laparoscopic techniques do not carry this risk, but not all individuals are candidates for this less-invasive approach.
Rapid weight loss after surgery: This complication puts people at high risk for gallstones.
Women who wish to be pregnant should wait until their weight has stabilized. Rapid weight loss and nutritional deficiencies can harm the fetus.

People at highest risk for complications are those with heart or lung problems, severe obesity, and a history of abdominal surgeries. The mortality rate from bariatric surgeries is 0.2%, which is lower than the morality rates from severe obesity itself. Other surgical variations and less invasive techniques using laparoscopy have been developed.

Specific Complications of Restrictive Banding Procedures. Nausea, vomiting, or both occurs in half the patients, and severe heartburn occurs in a third. Device-related complications include band slippage, pouch dilation (widening), or both in nearly a quarter of patients, and obstruction in 12% of patients. Very serious complications are rare, but include blood clots, bleeding, infection, pneumonia, and perforation (tearing) of the stomach.

Specific Complications of Malabsorptive Bypass Procedures. Vomiting often occurs. Nutritional deficiencies occur more often in these procedures. The so-called dumping syndrome is a common unpleasant side effect, which occurs when food waste moves too quickly through the intestine. Symptoms include nausea, weakness, sweating, and faintness (particularly after eating sweets).

Spot Exercising. Anyone seeking to lose weight must expect that the results may not be as cosmetically satisfying as one would wish. Spot exercising (training particular areas of the body) is ineffective in reducing fat in specific locations because exercise draws on fat stores throughout the body. Gimmicky devices such as bust developers, vacuum pants, and exercise belts do absolutely nothing to reduce fat or add bulk in specific locations. Electrical pads wrapped around the waist, arms, or thighs were reported to cause burns and fires.

Cellulite-Removal Creams. Many women try to reduce fat in their thighs (cellulite) with creams that contain aminophylline (Skinny Dip, Thermojetics Body Toning Cream, Smooth Contours). Studies provide no evidence that these creams are effective. Their apparent effect on fat may simply be from narrowing blood vessels and forcing water from the skin, which could be dangerous for people with blood flow problems.

Endermologie. Endermologie uses motorized rollers and regulated suction to smooth out cellulite. In one study, about 28.6% of patients reported improved appearance after using it.

Liposuction. Liposuction eliminates fat in specific areas, such as the abdomen, thighs, buttocks, or knees. Special instruments are inserted through the skin into the pockets and suction is used to move the fat, break it up, and remove it. Small tubes may be used to drain blood and fluid during the first few days. The pain after the operation can be severe and often the skin does not contract, resulting in a flabby look. Complications can include burns from the vibrators, bruising, blood clots, and bleeding. Weight gain generally tends to develop in other locations after the operation. Some doctors are using this procedure in overweight people with diabetes to remove abdominal fat. Although there is no proof that it has an effect on diabetes, some experts believe the procedure deserves attention.

Liposuction is not recommended for major weight loss.

Resources

www.healthierus.gov/dietaryguidelines -- Dietary Guidelines for Americans 2005
www.naaso.org -- North American Association for the Study of Obesity
www.eatright.org -- American Dietetic Association
www.nutrition.gov. -- Nutrition.gov
www.asbs.org -- American Society for Bariatric Surgery
www.cnpp.usda.gov -- Center for Nutrition Policy and Promotion
http://fnic.nal.usda.gov -- Food and Nutrition Information Center
www.americanheart.org -- American Heart Association
www.nationaleatingdisorders.org -- National Eating Disorders Organization
www.aabt.org -- Association for Advancement of Behavior Therapy
www.fda.gov -- Food and Drug Administration
http://win.niddk.nih.gov -- Weight-Control Information Network

References

US Food and Drug Administration FDA Approves Orlistat for Over-the-Counter Use. Rockville, MD: National Press Office; February 7, 2007.

Ogden CL, Carroll MD, Curtin LR, McDowell MA, Tabak CJ, Flegal KM. Prevalence of overweight and obesity in the United States, 1999-2004. Journal of the American Medical Association. 2006; 295:1549-1555.

National Center for Health Statistics. Chartbook on Trends in the Health of Americans. Health, United States, 2005. Hyattsville, MD: Public Health Service. 2005

National Institute of Diabetes and Digestive and Kidney Diseases - Weight-control Information Network. Statistics Related to Overweight and Obesity. Available online.

National Center for Health Statistics. Prevalence of Overweight Among Children and Adolescents: United States, 2003-2004.

Morino M, Toppino M, Bonnet G, Rosa R, et al. Laparoscopic vertical banded gastroplasty for morbid obesity. Assessment of efficacy. Surg Endosc. 2002 Nov;16(11):1566-72.

Brethauer SA, Schauer PR, Chand B. Risks and benefits of bariatric surgery: Current evidence. Cleveland Clinic Journal Of Medicine. 2006 Nov; 73(11): 993-1007.

Rosenthal RJ, Szomstein S, Kennedy CI, et al. Laparoscopic surgery for morbid obesity: 1,001 consecutive bariatric operations performed at The Bariatric Institute, Cleveland Clinic Florida. Obes Surg. 2006 Feb;16(2):119-24.

He K, Liu K, Daviglus ML, et al. Magnesium Intake and Incidence of Metabolic Syndrome Among Young Adults. Circulation. 2006: Published online before print. March 27, 2006.

Chen TY, Smith W, Rosenstock JL, Lessnau KD. A life-threatening complication of Atkins diet. Lancet. 2006 Mar 18;367(9514):958.

Lopez-Jimenez F, Bhatia S, Collazo-Clavell ML, Sarr MG, Somers VK. Safety and efficacy of bariatric surgery in patients with coronary artery disease. Mayo Clin Proc. 2005 Sep;80(9):1157-62.

Sidhaye A, Cheskin LJ. Pharmacologic treatment of obesity. Adv Psychosom Med. 2006;27:42-52.

Fernstrom JD, Courcoulas AP, Houck PR, Fernstrom MH. Long-term changes in blood pressure in extremely obese patients who have undergone bariatric surgery. Arch Surg. 2006 Mar;141(3):276-83.

Despres JP, Golay A, Sjostrom L; Rimonabant in Obesity-Lipids Study Group. Effects of rimonabant on metabolic risk factors in overweight patients with dyslipidemia. N Engl J Med. 2005 Nov 17;353(20):2121-34.

Lanningham-Foster L, Nysse LJ, Levine JA. Labor saved, calories lost: the energetic impact of domestic labor-saving devices. Obes Res. 2003 Oct;11(10):1178-81.

Review Date:
6/14/2007
Reviewed By:
A.D.A.M. Editorial Team: Greg Juhn, M.T.P.W., David R. Eltz, Kelli A. Stacy. Previously reviewed by Harvey Simon, MD, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital (4/30/2007).

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A.D.A.M. Copyright

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adam.com

How Many Glasses of Water Do You Drink Daily?

FitSugar — Mon, 03 Aug 2009 08:00:56 -0700

The health benefits of drinking eight 8-ounce glasses of water continue to fall under scrutiny. However, being dehydrated can slow down your metabolism. When it is hot and humid, and you're exercising regularly, it is important to stay hydrated by drinking water before, during, and after working out. With all this in mind, I want to know, on average . . .

Hypothyroidism

FitSugar — Wed, 08 Oct 2008 17:35:30 -0700

In This Report

Highlights
Introduction
Causes
Symptoms
Diagnosis
Risk Factors
Complications
Treatment
Resources
References

HEALTH GUIDE REFERENCE FROM A.D.A.M

Highlights

Congenital Hypothyroidism and Maternal Hyperthyroidism

Thyroid-lowering medications used for treating Graves’ disease, the most common cause of hyperthyroidism (overactive thyroid), can cause babies to be born with hypothyroidism (underactive thyroid). Research presented at the 2006 annual meeting of the American Thyroid Association suggests that hyperthyroidism can be effectively managed during pregnancy without causing newborn hypothyroidism. The researchers suggest that:

Pregnant women with Graves’ disease should take the lowest possible dose of their thyroid medication
It is safe for women with Graves’ disease to maintain thyroid levels in the upper-normal range while pregnant

Low-Normal Thyroid and Metabolic Syndrome

Thyroid levels in the low-normal range may increase the risk of unhealthy cholesterol levels, high blood sugar, and abdominal obesity -- indicators of metabolic syndrome -- according to a 2006 study in the Journal of Clinical Endocrinology and Metabolism.
Metabolic syndrome is a cluster of conditions, (including abdominal obesity, high blood sugar, and unhealthy cholesterol levels), which increases the risk for heart disease. However, many experts do not believe that treating subclinical hypothyroidism (mildly underactive thyroid) can help prevent heart problems. More research is underway.

Subclinical Hypothyroidism and Mood

A large study of elderly people, published in the Annals of Internal Medicine, suggests that subclinical hypothyroidism does not cause depression, anxiety, or impaired cognition. The study included nearly 6,000 people age 65 years and older.

Introduction

The thyroid is a small, butterfly-shaped gland located in the front of the neck that produces hormones, notably thyroxine (T4) and triiodothyronine (T3), which stimulate vital processes in every part of the body. These thyroid hormones have a major impact on the following functions:

Growth
Use of energy and oxygen
Heat production
Fertility
The use of vitamins, proteins, carbohydrates, fats, electrolytes, and water
Immune regulation in the intestine

These hormones can also alter the actions of other hormones and drugs.

The thyroid gland, a part of the endocrine (hormone) system, plays a major role in regulating the body's metabolism.

Regulating thyroid function is a complex and important process that involves several factors, including iodide and four thyroid hormones. Any abnormality in this intricate system of hormone synthesis and production can have far-reaching consequences on health.

Iodide. An understanding of the multi-step thyroid hormone process begins with iodide, a salt that is extracted from the blood and trapped by the thyroid gland. Iodide is converted to iodine in the thyroid gland. (Eighty percent of the body's iodine supply is stored here.) Iodine is the material used to make the hormone thyroxine (T4).

Thyroid Hormones. Four hormones are critical in the regulation of thyroid function:

Thyroxine (T4) and Triiodothyronine (T3). Thyroxine (T4) is the key thyroid hormone. Low levels of T4 produce hypothyroidism, and high levels produce hyperthyroidism. Thyroxine converts to triiodothyronine (T3), which is a more biologically active hormone. Only about 20% of triiodothyronine is actually formed in the thyroid gland. The rest is manufactured from circulating thyroxine in tissues outside the thyroid, such as those in the liver and kidney. Once T4 and T3 are in circulation, they typically bind to substances called thyroid hormone transport proteins, after which they become inactive.
Thyrotropin. Thyrotropin (also called thyroid-stimulating hormone or TSH) is another very important hormone in the process. Secreted by the pituitary gland, this hormone directly influences the process of iodine trapping and thyroid hormone production. When thyroxine levels drop even slightly, the pituitary gland goes into action to pump up secretion of thyrotropin so that it can stimulate thyroxine production. So, when T4 levels fall, TSH levels increase.
Thyrotropin-releasing hormone (TRH), the final critical thyroid hormone, is produced in a region in the brain called the hypothalamus, which monitors thyrotropin levels.

Click the icon to see an image of the pituitary gland.

Click the icon to see an image of the pituitary gland and TSH.

Hypothyroidism occurs when thyroxine (T4) levels drop so low that body processes begin to slow down. Hypothyroidism was first diagnosed in the late nineteenth century when doctors observed that surgical removal of the thyroid resulted in the swelling of the hands, face, feet, and tissues around the eyes. They named this syndrome myxedema and correctly concluded that it was the outcome of the absence of substances, thyroid hormones, normally produced by the thyroid gland. Hypothyroidism is usually progressive and irreversible. Treatment, however, is nearly always completely successful and allows a patient to live a fully normal life.

Subclinical hypothyroidism (mildly underactive thyroid), also called early-stage hypothyroidism, is a condition in which thyrotropin (TSH) levels have started to increase in response to an early decline in T4 levels in the thyroid. However, blood tests for T4 are still normal. The patient may have mild symptoms (usually slight fatigue) or none at all. Mildly underactive thyroid is very common (affecting about 10 million Americans) and is a topic of considerable debate among professionals because it is not clear how to manage this condition.

For instance, mildly underactive thyroid does not progress to the full-blown disorder in most people. Experts estimate that each year approximately 2 - 5% of people with mildly underactive thyroid will go on to develop overt hypothyroidism. Other factors associated with a higher risk include being an older woman (up to 20% of women over age 60 have subclinical hypothyroidism), having a goiter (enlarged thyroid gland) or thyroid antibodies, or harboring immune factors that suggest an autoimmune condition.

Mildly underactive thyroid is determined on the basis of the TSH laboratory blood tests. According to a 2004 consensus statement from the American Thyroid Association, the American Association of Clinical Endocrinologists, and the Endocrine Society, the normal range of TSH concentration falls between 0.45 and 4.5 mU/L. Patients with mildly underactive thyroid have TSH levels between 4.5 mU/L and 10mU/L. Patients with levels greater than 10mU/L are considered to have overt hypothyroidism and should be treated with medication.

For patients in the mildly underactive thyroid range, treatment decisions are less clear. The consensus committee recommended against routine treatment for patients with mildly underactive thyroid , but did suggest repeat screenings of thyroid function every 6 - 12 months to detect any changes in TSH levels. However, these are general guidelines, and individual cases and risk factors may differ. Patients should discuss with their doctor the course of action that is most appropriate for them.

Causes

Many permanent or temporary conditions can reduce thyroid hormone secretion and cause hypothyroidism. About 95% of hypothyroidism cases occur from problems that originate in the thyroid gland. In such cases, the disorder is called primary hypothyroidism. (Secondary hypothyroidism is caused by disorders of the pituitary gland. Tertiary hypothyroidism is caused by disorders of the hypothalamus.)

The two most common causes of primary hypothyroidism are:

Hashimoto's thyroiditis. This is an autoimmune condition in which the body's immune system attacks its own cells.
Overtreatment of hyperthyroidism (an overactive thyroid).

Hashimoto's thyroiditis, atrophic thyroiditis, and postpartum thyroiditis are all autoimmune diseases of the thyroid. An autoimmune disease occurs when the immune system mistakenly attacks the body's own healthy cells. In the case of autoimmune thyroiditis, a common form of primary hypothyroid disease, the cells under attack are in the thyroid gland.

All forms of thyroid autoimmunity typically start with T and B cells:

Important immune factors called T and B cells infiltrate the thyroid gland in equal numbers. These white blood cells are the primary infection-fighting immune cells. T cells identify invasive molecules, such as viral proteins, and help B cells to produce antibodies that are designed specifically to attack these invaders.
In cases of autoimmunity, T cells are tricked into classifying molecules on the body's own cells as invaders. In such cases, B cells then produce antibodies, called autoantibodies, which attack those cells.
In most cases of thyroid autoimmunity, the autoantibodies launch an attack on a thyroid protein called thyroid peroxidase; this attack appears to destroy thyroid cells.

Experts do not know why the immune system starts the process that injures the thyroid. Some theories follow:

One theory starts with a virus that has a protein resembling a thyroid protein. During an infection, T cells induce B cells to secrete specific antibodies that attack the invasive viral protein. Unfortunately, the T cells are also tricked into inducing a B-cell attack on the similar thyroid protein.
Genetic factors most likely play some role in autoimmune thyroiditis. For example, many patients with Hashimoto's thyroiditis express a gene called the Fas gene, which interacts with thyroid cells and triggers a process called apoptosis, in which the cells begin to self-destruct. The Fas gene is linked to genes that regulate tumor necrosis factors, which are products of the immune system that trigger a damaging inflammatory response in cells.
In some women, thyroid autoimmunity may have developed while they were pregnant. In such cases, some evidence suggests that fetal cells accumulated in the mother's thyroid gland, triggering an immune attack.
In some cases of Hashimoto's thyroiditis, antibodies block a receptor on thyroid cells that bind to thyrotropin (TSH). This effect is more likely to be involved in worsening the disorder, but does not explain initial destruction.
Some evidence suggests that excess iodine intake triggers the process leading to Hashimoto's thyroiditis.

Hashimoto's Thyroiditis. The most common form of hypothyroidism in the U.S. is Hashimoto's thyroiditis, a genetic disease named after the Japanese doctor who first described thyroid inflammation. It occurs in about 0.3 - 5 people per 1,000 per year, and women are 15 - 20 times more likely than men to develop this disease.

Click the icon to see an image of Hashimoto's thyroiditis.

An enlargement of the thyroid gland, called a goiter, is almost always present and may appear as a cyst-like or fibrous growth in the neck. Hashimoto's thyroiditis is permanent and requires lifelong treatment. Both genetic and environmental factors appear to play a role in its development.

One theory proposes that Hashimoto's thyroiditis and Graves' disease (a form of hyperthyroidism) are caused by a similar immunologic dysfunction. Similar immune system substances called antibodies are present in both diseases, and some experts believe that the predominance of one or another antibody determines which of the diseases become manifest. The two diseases, then, are essentially two sides of a single coin.

Click the icon to see an image of Grave's disease.

Atrophic Thyroiditis. Atrophic thyroiditis is similar to Hashimoto's thyroiditis, except a goiter is not present.

Riedel's Thyroiditis. Riedel's thyroiditis is a rare autoimmune disorder, in which scar tissue progresses in the thyroid until it produces a hard stony mass that suggests cancer. Hypothyroidism develops as the scar tissue replaces healthy tissue. Surgery is usually required, although early stages may be treated with tamoxifen, corticosteroids, or other immunosuppressive drugs.

Autoimmune Thyroiditis Due to Pregnancy. Hypothyroidism may also occur in women who develop antibodies to their own thyroid during pregnancy, causing an inflammation of the thyroid after delivery.

Subacute thyroiditis is a temporary condition that passes through three phases: hyperthyroidism, hypothyroidism, and a return to normal thyroid levels. Patients may exhibit symptoms of both hyperthyroidism and hypothyroidism (rapid heartbeat, nervousness, weight loss), and they can feel extremely sick. Symptoms last about 6 - 8 weeks and then resolve in most patients, although each form carries some risk for becoming chronic. Experts estimate that subacute thyroiditis is responsible for 10% of all cases of hypothyroidism.

The three forms of subacute thyroiditis follow a similar course:

Painless Postpartum Subacute Thyroiditis. Postpartum thyroiditis is an autoimmune condition that occurs in up to 10% of pregnant women and tends to develop between 4 - 12 months after delivery. In most cases, a woman develops a small, painless goiter. Although 80% of women with this condition have normal thyroid function within a year, some evidence suggests that half of women with this condition develop permanent hypothyroidism within 7 years. Women who have had recurrent episodes after previous pregnancies and women who have other autoimmune disorders are at higher risk for this form of subacute thyroiditis. It is generally self-limiting and requires no therapy unless the hypothyroid phase is prolonged. In such cases, therapy may be thyroxine replacement for a few months. A doctor will prescribe beta blockers if the hyperthyroid phase requires treatment.

Painless Sporadic, or Silent, Thyroiditis. This painless condition is very similar to postpartum thyroiditis except it can occur in both men and women and at any age. About 20% of patients with silent thyroiditis may develop chronic hypothyroidism. Treatment considerations are the same as for postpartum subacute thyroiditis.

Painful, or Granulomatous, Thyroiditis. This condition comes on suddenly with flu-like symptoms and severe neck pain and swelling. It generally occurs in the summer and is five times more common in women. It recurs in about 2% of patients. Hypothyroidism persists in about 5%. Treatments typically include pain relievers and, in severe cases, corticosteroids.

Up to half or more of patients who receive radioactive iodide treatments for an overactive thyroid develop permanent hypothyroidism within a year of therapy. This is the standard treatment for Graves' disease, which is the most common form of hyperthyroidism, a condition caused by excessive secretion of thyroid hormones.

By the end of 5 years, about 65% of treated patients have developed hypothyroidism, after which the rate of this condition levels off to about 1% a year. Such patients need to take thyroid hormones for the rest of their lives. Other forms of treatment for overactive thyroid glands using either antithyroid drugs or surgery may also result in hypothyroidism.

Too much or too little iodide can cause hypothyroidism. If there is a deficiency of iodide, the body cannot manufacture thyroxine. About 200 million people around the world have hypothyroidism because of insufficient iodine in their diets. Too much iodide is a signal to inhibit the conversion process of thyroxine to T3. The end result in both cases is inadequate production of thyroid hormones. Some evidence suggests that excess iodine triggers the process leading to Hashimoto's thyroiditis.

Complete removal (total thyroidectomy) of the thyroid to treat thyroid cancer requires a lifetime of treatment with an appropriate dosage of thyroid hormone. Removing one of the two lobes of the thyroid gland (hemithyroidectomy), usually because of benign growths on the thyroid gland, rarely produces hypothyroidism. The remaining thyroid lobe will generally enlarge so that it can produce sufficient amounts of thyroid hormone for normal function. Many doctors recommend thyroid hormone treatment, however, to prevent the formation of additional nodules.

Click the icon to see an illustrated series detailing thyroid removal.

A small percentage of Graves disease patients who require surgery to remove most of both thyroid lobes (subtotal thyroidectomy) may develop hypothyroidism. It is important to find an experienced surgeon for this procedure and to have the thyroid checked at 6- or 12-month intervals.

Researchers have identified several additional syndromes that also cause hypothyroidism. These generally involve abnormalities in thyroid hormone itself or genetic deficiencies in certain proteins that impair thyroid hormone conversion processes or responses.

Lithium. Lithium, a drug widely used to treat psychiatric disorders, has multiple effects on thyroid hormone synthesis and secretion. Up to 50% of patients who take lithium develop a goiter, with 20% developing symptomatic hypothyroidism, and another 20 - 30% developing hypothyroidism without symptoms.

Amiodarone. The drug amiodarone (Cordarone), which is used to treat abnormal heart rhythms, contains high levels of iodine and can induce hyper- or hypothyroidism, particularly in patients with existing thyroid problems. Hypothyroidism occurs in 20% of patients and is the more common effect in the U.S. and other countries where dietary iodine is abundant. Hyperthyroidism is a less common effect in these regions.

Other Drugs. Drugs used for treating epilepsy, such as phenytoin and carbamazepine, can reduce thyroid levels. Certain antidepressants may cause hypothyroidism, although this is rare. Interferons and interleukins are used for treating hepatitis, multiple sclerosis, and other conditions. Evidence suggests that these drugs increase antibodies that put patients at risk for hypo- or hyperthyroidism. Some drugs used in cancer chemotherapy, such as sunitinib (Sunent) or imatinib (Gleevec), can also cause or worsen hypothyroidism.

High-dose radiation for cancers of the head or neck and for Hodgkin's disease causes hypothyroidism in up to 65% of patients within 10 years after treatment.

In rare instances, usually due to a tumor, the pituitary gland will fail to produce thyrotropin (TSH), the hormone that stimulates the thyroid to produce its hormones. In such cases, the thyroid gland withers. When this happens, secondary hypothyroidism occurs.

Hypothyroidism in newborns (known as congenital hypothyroidism) occurs in one in every 3,000 - 4,000 births, making it the most common hormonal disorder in infants. In 90% of these cases, it persists throughout life.

Permanent Congenital Hypothyroidism. In up to 85% of permanent congenital hypothyroidism cases, the thyroid gland is missing, underdeveloped, or not properly located. In most cases the cause or causes of these conditions are unknown. In about 10 - 15% of cases, processes involved in hormone production are impaired, most likely because of genetic abnormalities. In less than 5% of cases, the pituitary or hypothalamus function abnormally.

Temporary Hypothyroidism in Infants. Temporary hypothyroidism can also occur in infants. In about 20% of cases, the cause remains unknown. The known causes stem from various immunologic, environmental, and genetic factors, including those in the mother:

Hypothyroidism. Women who have an underactive (“low”) thyroid, including those who develop the problem during pregnancy, are at increased risk for delivering babies with congenital (newborn) hypothyroidism. Maternal hypothyroidism can also cause premature delivery and low-birth weight.
Hyperthyroidism. Graves disease is the most common cause of maternal hyperthyroidism (overactive or “high” thyroid). Some of the drugs used to treat hyperthyroidism can cause hypothyroidism in the infant. Some research indicates that using the lowest possible dose of thyroid-lowering medication can minimize the risk of congenital hypothyroidism. (The research also suggests that it is safe for women with Graves’ disease to remain in a mildly hyperthyroid state during pregnancy.
Iodine deficiency. This may cause temporary hypothyroidism. (Exposure to too much iodine immediately after birth, for example, from iodine-containing disinfectants or medicines, can also cause thyroid dysfunction.)
Being premature.
Kidney disease. Temporary hypothyroidism in infants can occur in premature babies and, rarely, in those with kidney disease.
The central nervous system connections between the hypothalamus and pituitary gland may also mature late; this condition generally resolves 4 - 16 weeks after birth.

Children with temporary congenital hypothyroidism should be followed-up regularly during adolescence and adulthood for possible thyroid problems. The risk for further thyroid problems is highest in these adult women during pregnancy. Newborn siblings of these children should also be screened for possible thyroid defects.

Symptoms

Early Symptoms. Early symptoms of hypothyroidism are subtle and, in older people, can be easily mistaken for symptoms of stress or aging. They include:

Chronic fatigue
Sensitivity to cold
Headache
Muscle and joint aches
Weight gain, despite diminished appetite
Constipation
Dry skin

In premenopausal women, early symptoms can interfere with fertility. They may experience heavy periods or, in rare cases, a milky discharge from the breasts. A history of miscarriage may be a sign of impending hypothyroidism. Studies suggest that even if thyroid levels are normal, women who have a history of miscarriages often have antithyroid antibodies during early pregnancy and are at risk for developing autoimmune thyroiditis over time.

Later Symptoms. As free thyroxine levels fall over the following months, other symptoms may develop:

Impaired mental activity, including concentration and memory, particularly in the elderly.
Depression. Some experts believe that even mild thyroid failure may increase susceptibility to major depression.
Muscle weakness, numbness, pain, and cramps. This can cause an unsteady gait. Muscle cramps are common, and carpal tunnel syndrome or symptoms similar to arthritis sometimes develop. In some cases, the arms and legs may feel numb.
Numbness in the fingers.
Hearing loss.
Husky voice.
Continuing weight gain and possible obesity, in spite of low appetite.
Some people experience less sweating, and their skin becomes pale.
Skin and hair changes. Skin becomes pale, rough, and dry. Patients may sweat less. Hair coarsens and even falls out. Nails become brittle.
Snoring and obstructive sleep apnea (a condition in which in the soft palate in the throat collapses at intervals during sleep, thereby blocking the passage of air).

Secondary hypothyroidism, caused by tumors or other growths on the pituitary, produces the usual symptoms of primary hypothyroidism. In addition, sexual drive and fertility may be impaired in both men and women. Patients may also feel exhausted, crave salt, and have low blood pressure. Headaches and visual disturbances may develop, which are directly related to the pituitary tumor.

Hypothyroidism occurs when the thyroid gland is underactive. The condition may affect all body functions. The rate of metabolism slows, causing mental and physical sluggishness. Myxedema, a medical emergency, is the most severe form of hypothyroidism. A problem with the thyroid itself (primary) or malfunction of the pituitary gland (secondary) or hypothalamus (tertiary) can cause hypothyroidism.

All babies are now screened for hypothyroidism in order to prevent retardation that can occur if treatment is delayed. Symptoms of hypothyroidism in children vary depending on when the problem first develops.

Most children who are born with a defect that causes congenital hypothyroidism have no obvious symptoms. Symptoms that do appear in newborns may include jaundice (yellowish skin), noisy breathing, and an enlarged tongue.
Early symptoms of undetected and untreated hypothyroidism in infants include feeding problems, failure to thrive, constipation, hoarseness, and sleepiness.
Later on, symptoms in untreated children include protruding abdomens; rough, dry skin; and delayed teething. Rarely, in advanced cases, yellow raised bumps (called xanthomas) may appear under the skin, the result of cholesterol build-up.
If they do not receive proper treatment in time, children with hypothyroidism may be extremely short for their age, have a puffy, bloated appearance, and have below-normal intelligence. Any child whose growth is abnormally slow should be examined for hypothyroidism.

Diagnosis

Advances in diagnostic methods now make it possible to detect hypothyroidism in almost all cases before severe symptoms develop. Doctors can diagnosis hypothyroidism after completing a history and physical exam of the patient and performing sensitive laboratory tests on the patient's blood.

The doctor will check the heart, eyes, hair, skin, and reflexes for signs of hypothyroidism.

Goiter. The presence of a goiter (an enlarged thyroid), especially a rubbery, painless one, may be an indication of Hashimoto's disease. If the thyroid is tender and enlarged but not necessarily symmetrical, the doctor may suspect subacute thyroiditis. A diffusely enlarged gland may occur in hereditary hypothyroidism, in postpartum patients, or from use of iodides or lithium. Goiters may also develop in people with iodide deficiency.

Thyroid Neck Check. Women who are experiencing menopausal symptoms that may be masking those of hypothyroidism should perform a simple self-examination called the Thyroid Neck Check:

Hold a mirror in front of the area of the neck where the thyroid gland is located. This area is just below the Adam's apple and right above the collarbone. (Note: The Adam's apple is not the thyroid location.)
Tip the head back.
Take a drink of water and swallow, watching the neck during the process.
Check for any bulging or protrusions. If any is detected, call a doctor for a check up.

In diagnosing hypothyroidism, blood tests measuring hormone levels are needed to make a correct diagnosis. In some cases, antibody tests are also helpful.

Thyroxine (T4). Hypothyroidism is a condition marked by low thyroxine (T4) hormone levels, and a test can measure levels of this hormone in the blood. However, this test is usually inadequate for the following reasons:

T4 levels can be normal early in the disease process leading to hypothyroidism. If hypothyroidism is suspected, other tests are needed.
T4 levels can be low in patients who do not have hypothyroidism. For instance, thyroxine can be extremely variable in very elderly or seriously ill patients and during pregnancy.

Measuring thyroxine is usually performed using a process called a T3 resin uptake to correct for the presence of medications (such as birth control pills, aspirin, and others) that could distort the results. Other tests are needed to confirm a diagnosis of hypothyroidism.

Thyrotropin (Thyroid-Stimulating Hormone or TSH). Measuring TSH is the most sensitive indicator of hypothyroidism. (As with thyroxine levels, however, TSH levels can vary in pregnant women and patients who are ill with other conditions.) In general, results indicate the following:

TSH levels over 10mU/L. This is a clear indicator of hypothyroidism if T4 levels are low -- and, in most cases, even if they are normal. Patients usually require thyroxine (T4) replacement therapy. They should also be tested for high cholesterol levels and antithyroid antibodies.
Levels between 4.5 mU/L - 10 mU/L. Patients with signs and symptoms of hypothyroidism usually need thyroxine replacement therapy. Patients without symptoms have subclinical hypothyroidism and should be rechecked every 6 - 12 months. Antibody tests may also be performed.
TSH levels between 0.45 mU/L - 4.5 mU/L. These indicate normal thyroid function. (Abnormally low levels suggest hyperthyroidism, which is overactive thyroid.)
Specific TSH measurement -- even if it is significantly higher than 10 mU/L -- is not associated with the severity of the condition. This can be determined only by measuring thyroxine levels and evaluating the patient's symptoms.

Antithyroid Antibodies. If TSH levels suggest hypothyroidism or subclinical hypothyroidism, the doctor may choose to perform a blood test for specific antithyroid antibodies that act against a factor called thyroperoxidase (TPO). Tests can also check for antibodies to thyroglobulin. Results depend on the patient's condition:

Patients with confirmed hypothyroidism (TSH levels over 10 mU/L). Positive test results in such patients confirm the need for thyroxine replacement therapy. (Even if antibody results are negative, these patients usually require thyroxine replacement therapy.) About 90% of patients with Hashimoto's thyroiditis test positive for antibodies to thyroperoxidase, and up to half have thyroglobulin antibodies.
Patients with subclinical hypothyroidism (TSH between 4.5 mU/L - 10 mU/L). If antibody levels are high, thyroxine therapy is usually warranted, since it indicates an underlying autoimmunity condition that poses a high risk for later thyroid failure. If the tests are negative, but patients have thyroid-related problems (such as high cholesterol, female infertility), they should be monitored annually with hormone tests.

About 10% of the American population and 25% of women over 60 years old carry these antibodies, and the majority of these women have no thyroid problems. Only about 0.5% have full-blown hypothyroidism, and 10% have subclinical hypothyroidism. In one 10-year study, however, people with normal thyroid results and high levels of antibodies still had an annual risk of 2 - 4% for developing hypothyroidism.

Other Hormone Tests Used for Thyroid Function. Other hormone tests are done if hyperthyroidism is suspected. They include tests for triiodothyronine (T3) and thyroglobulin (also called thyroid binding globulin). Such measurements, however, may also be helpful in detecting sudden temporary increases in thyroid hormone (thyrotoxicosis) that can precede certain forms of autoimmune thyroiditis.

Thyroid Scintigraphy. Thyroid scintigraphy tests scan the thyroid and pick up images highlighted by small amounts of radioactive substances. Thyroid scans can be used to determine whether the thyroid is producing normal amounts of hormone. The patient drinks a small amount of radioactive iodine or technetium and waits until the substance has passed through the thyroid. Images of a properly functioning thyroid would show uniform levels of absorption throughout the gland. Overactive areas show up white, and underactive areas appear dark. Thyroid scans are usually unnecessary unless the doctor needs to rule out suspected cancer.

Ultrasound. Ultrasound has limited value, but it can visualize the thyroid and specific abnormalities, such as nodules. (It cannot measure the thyroid gland's function, however.)

Click the icon to see an image of thyroid ultrasound.

More Advanced Imaging Tests. If laboratory tests suggest that a pituitary or hypothalamus problem is causing hypothyroidism, the doctor will usually order brain imaging procedures using computed tomography (CT) scans or magnetic resonance imaging (MRI). MRIs may also be used for determining the extent of thyroid cancers and of goiters. MRIs are also being used for investigating hypothyroidism in infants and for determining widespread effects of autoimmune thyroiditis (such as Hashimoto's hypothyroidism).

Needle aspiration biopsy is used to obtain thyroid cells for microscopic evaluation. It may be useful to rule out thyroid cancer in patients with suspected Hashimoto's hypothyroidism, especially if they have difficulty swallowing or develop a goiter. Much like drawing blood, the doctor injects a small needle into the thyroid gland and draws cells from the gland into a syringe. The cells are put onto a slide, stained, and examined under a microscope.

Cholesterol levels need to be checked. Other blood tests may be performed to detect levels of calcitonin, calcium, prolactin, and thyroglobulin and to check for anemia and liver function, all of which may be affected by hypothyroidism.

Screening in Older Adults. Some doctors believe that because thyroid problems are so common in the elderly and thyroid hormone tests are so inexpensive, blood tests for thyroid function should be routine. Undiagnosed hypothyroidism in elderly patients can develop into a serious and even life-threatening situation. Hyperthyroidism also poses many health risks. In fact, during the period around menopause, the symptoms of menopause and hypothyroidism are similar and can easily be confused with each other.

Professional organizations differ widely on screening recommendations. Most do not recommend widespread screening for healthy adults:

The American College of Physicians recommends that women over 50 years old be screened for thyroid disorders every 5 years. The American Academy of Family Physicians believes that adults do not have to be screened until they are over 60.
The American Thyroid Association, however, recommends that all adults, both men and women, begin their screening at age 35 and every 5 years thereafter. Experts in this organization argue that such early screening is inexpensive and would prevent progression to hypothyroidism, and therefore possibly heart disease, in people with subclinical hypothyroidism. Such an approach would also eliminate the need for expensive anti-cholesterol drugs.

Screening in Pregnant Women. Untreated hypothyroidism in a pregnant woman, particularly in the first trimester, may cause premature delivery and birth defects. Birth defects can affect a baby’s intelligence, mental development, and motor skills. Subclinical hypothyroidism also increases the risk for premature delivery and birth defects.

Some experts propose that screening be done on any woman who is planning a pregnancy to help determine those who may be at increased risk for hypothyroidism and, if needed, begin treatment as early as possible during the critical first trimester. Women who have a personal or family history of hypothyroidism should have their thyroid checked within the first weeks of pregnancy and should be retested during each trimester.

Screening in Infants. It is very difficult to diagnose hypothyroidism in newborns by symptoms alone. Fortunately, almost all newborns with hypothyroidism are identified shortly after birth through an effective national screening program using a thyroid blood test.

Because the symptoms of hypothyroidism are so similar to common conditions, including aging, diagnosis can be difficult.

Conditions That Cause Thyroid Abnormalities. Some conditions may cause thyroid abnormalities without symptoms and must be differentiated from subclinical hypothyroidism. They include, although are not limited to:

Inadequate response to thyroid therapies in people with hypothyroidism
Recovery from a severe illness that is unrelated to thyroid disorders
Chronic kidney failure
Failure of the adrenal gland

Aging-Related Disorders. Some symptoms of hypothyroidism and aging are very similar. Menopausal symptoms often resemble hypothyroidism. Many other problems related to aging -- such as vitamin deficiencies, Parkinson's and Alzheimer's diseases, and arthritis -- also have characteristics that can mimic hypothyroidism.

Obesity. Many people who are overweight believe that they have an underactive thyroid gland, but only a very small percentage of obese people actually have hypothyroidism. Patients with hypothyroidism generally show only a moderate weight increase of 5 - 10 pounds, mainly from accumulation of fluid, and in fact they often have a decreased appetite.

Depression. A lack of interest in personal relationships, drowsiness, an increase in sleep, slowing of speech, and general apathy are signs of clinical depression as well as hypothyroidism. The two disorders often coexist, particularly in older women, so diagnosing one does not rule out the presence of the other.

Diseases of Muscles and Joints. Joint and muscle aches may be the first symptoms of hypothyroidism. Most likely, however, such pain is not caused by hypothyroidism if other thyroid symptoms remain absent. Numerous conditions can cause muscle and joint pain, and if thyroid levels are normal the doctor should look for other causes.

Risk Factors

About 15 million Americans have unrecognized thyroid disease, mostly subclinical hypothyroidism (mildly underactive thyroid). Less than 2% of the U.S. population has full-blown hypothyroidism.

Women. Women have 10 times the risk of hypothyroidism as men, with the difference being significant after age 34. In one study, nearly 6% of women over 60 had hypothyroidism, and some experts estimate that as many as 20% of women in this age group have a subclinical condition. Because the symptoms of hypothyroidism and menopause are so similar, hypothyroidism may easily be missed.

Pregnancy is a major factor in the higher risk in women. It affects the thyroid in a number of ways and poses a high risk for hypothyroidism, both during pregnancy and afterward. For one, iodine requirements are high in both the mother and the fetus. Changes in reproductive hormones also cause changes in thyroid hormone levels. In addition, some women develop antibodies to their own thyroid during pregnancy, causing a condition known as postpartum autoimmune, or subacute, thyroiditis. This occurs in up to 10% of pregnant women and tends to develop between 4 - 12 months after delivery. It is a limited condition and nearly always clears up. However, it does pose a risk for the development of permanent hypothyroidism later on.

Age. The elderly are most susceptible, but hypothyroidism can affect people of all ages. For example, 1 in every 3,000 - 4,000 infants is born with congenital hypothyroidism. Female infants are at higher risk than males.

Ethnicity. African-Americans may be less likely to have thyroid disease than Caucasians and Asians.

Genetics plays a role in many cases of underactive and overactive thyroid. The genetics involved with hypothyroidism are complicated, however. Certain genetic features, for example, appear to play a role in Hashimoto's thyroiditis and postpartum thyroiditis in Caucasians, but others affect different ethnic groups. Thyroid disease will often skip generations. For example, someone with an underactive thyroid may have healthy parents but have grandparents who had thyroid troubles. Some people inherit a tendency to thyroid problems but never become ill, while others become very sick.

Smoking significantly increases risk for thyroid disease, particularly autoimmune Hashimoto's thyroiditis and postpartum thyroiditis. Chemicals in cigarette smoke called thiocyanates appear to have especially harmful effects on the thyroid. Smoking also increases the negative effects of hypothyroidism, notably on the arteries and heart.

People with certain medical conditions have a higher risk for hypothyroidism. These conditions include:

Autoimmune diseases. People with many autoimmune diseases have a higher risk for hypothyroidism. Type 1 (insulin-dependent) diabetes poses a higher risk and is a special problem since hypothyroidism can affect insulin requirements. Women with other autoimmune diseases, including systemic lupus erythematosus, pernicious anemia, and rheumatoid arthritis, are also at higher risk for hypothyroidism. Pregnant women with autoimmune conditions have a 25% risk for hypothyroidism during gestation.
Breast cancer. There may be a link between breast cancer and thyroid levels, but the evidence is unclear. Some studies have indicated that women with breast cancer may be more susceptible to hypothyroidism. Other studies suggest the opposite. Several studies indicate that hypothyroidism itself may protect against breast cancer. In addition, when women with hypothyroidism develop breast cancer, it is often a less aggressive and more easily treated form.
Gout. Hypothyroidism and gout often coexist and may have biologic mechanisms in common.
Addison's disease.
Myasthenia gravis.
Polycystic ovarian syndrome.
Anorexia or bulimia. People with eating disorders are at risk for hypothyroidism. In these cases, however, reduced thyroid function may be an adaptation to malnutrition and, therefore, some experts think that only the eating disorder should be treated, not hypothyroidism.
Turner syndrome. As many as half of patients with Turner syndrome have hypothyroidism, usually in the form of Hashimoto's thyroiditis. This inherited condition is one of the most common genetic diseases in women.
Glaucoma. A 2004 study of male veterans suggested that hypothyroidism may be associated with increased risk for developing open-angle glaucoma.

Click the icon to see an animation about gout.

Click the icon to see an image of polycystic ovarian syndrome.

Many drugs affect the thyroid, so anyone being treated for a chronic disease, patients who are taking thyroid medication, and those who are at risk for a thyroid disorder should discuss the impact these drugs may have on their thyroid.

Hypothyroidism is associated with premature gray hair and left-handedness.

Complications

Hypothyroidism carries serious physical and mental risks for all ages. Studies indicate that subtle adverse health effects occur even with subclinical hypothyroidism, a condition in which the patient has no symptoms but blood tests indicate hypothyroidism. Fortunately, hypothyroidism is now easily diagnosed, and treatment will restore normal thyroid function and relieve symptoms and physical signs of the disease. With treatment, a patient should expect to live a normal life, free of harmful consequences. Iodine deficiency and goiter are still major problems in less developed nations and cause varying degrees of mental retardation in millions of people.

Myxedema Coma. Myxedema coma is a rare, life-threatening complication of untreated hypothyroidism. Symptoms include a severe drop in body temperature (hypothermia), delirium, reduced lung function, slow heart rate, constipation, urine retention, seizures, stupor, fluid build-up, and finally coma. It is uncommon, but may develop in untreated patients subjected to severe stress, such as infection, surgery, or extreme cold. Certain drugs (such as sedatives, painkillers, narcotics, amiodarone, and lithium) may increase the risk. Emergency treatment is required. Mortality rates are high (between 30 - 60%) with the highest risks in older patients and those with persistent hypothermia or heart problems.

Suppurative Thyroiditis. Suppurative thyroiditis is a life-threatening infection of the thyroid gland. It is very rare, since the thyroid is normally immune to infection. People with pre-existing thyroid diseases, such as Hashimoto's thyroiditis, however, may be at higher than average risk for it. It often begins with an upper respiratory infection. Symptoms include fever, neck pain and rash, and trouble swallowing and speaking. Immediate treatment is critical.

Thyroid hormones, notably triiodothyronine (T3), affect the heart directly and indirectly. They are closely linked with heart rate and heart output. T3 provides particular benefits by relaxing the smooth muscles of blood vessels. This helps keep the blood vessels open so that blood flows smoothly through them.

Hypothyroidism is associated with:

Unhealthy cholesterol levels. Hypothyroidism raises levels of total cholesterol, LDL (the so-called bad cholesterol), triglycerides, and other lipids (fat molecules) associated with heart disease. Treating the thyroid condition with thyroid replacement therapy can significantly reduce these levels.
Mild high blood pressure. Hypothyroidism may slow the heart rate to less than 60 beats per minute, reduce the heart's pumping capacity, and increase the stiffness of blood vessel walls. All of these effects may lead to high blood pressure. Indeed, patients with hypothyroidism have triple the risk of developing hypertension. All patients with chronic hypothyroidism, especially pregnant women, should have their blood pressures checked regularly.
Heart failure. Hypothyroidism can affect the heart muscle’s contraction and increase the risk of heart failure in people with existing heart disease.

The evidence for subclinical hypothyroidism and heart disease is mixed. Some studies suggest that subclinical hypothyroidism increases the risks for coronary artery disease and heart failure. A 2007 study indicated that low-normal thyroid function may increase the risk for metabolic syndrome (a cluster of symptoms that include abdominal obesity, high blood sugar, and unhealthy cholesterol levels). However, a 2006 study in the Journal of the American Medical Association found that while subclinical hypothyroidism was associated with atrial fibrillation (irregular heart beat), it was not associated with other types of heart disease. Many experts believe that treatment of subclinical hypothyroidism will not help prevent or improve heart problems. More research is underway.

Depression. Depression is common in hypothyroidism and can be severe. Some psychiatrists suspect that even subclinical hypothyroidism may contribute to depression. The two disorders may have some common physiological basis. Adding thyroid hormones to antidepressants may hasten a depressed patient's recovery, even in some patients who have not been diagnosed with hypothyroidism. Hypothyroidism should be considered as a possible cause of any chronic depression, particularly in older women.

Mental and Behavioral Impairment. Untreated hypothyroidism can, over time, cause mental and behavioral impairment and eventually, even dementia. Whether treatment can completely reverse problems in memory and concentration is uncertain, although many experts believe that only mental impairment in hypothyroidism that occurs at birth is permanent.

A 2006 study of nearly 6,000 people age 65 years and older concluded that subclinical hypothyroidism is not associated with depression, anxiety, or mental impairment in elderly patients.

The following medical conditions have been associated with hypothyroidism. Often the causal relationship is not clear in such cases:

Iron deficiency anemia.
Respiratory problems.
Kidney function.
Glaucoma. (Some research has associated hypothyroidism with an increased risk for glaucoma.)
Headache. (Hypothyroidism may worsen headaches in people predisposed to them.)
Thyroid lymphoma. (Patients with Hashimoto's thyroiditis are at higher risk for this rare form of cancer.)
Joint stiffness. (Women with hypothyroidism may actually have fewer problems with joint stiffness than women with normal thyroid.)

Most women with hypothyroidism fail to produce eggs, and many younger women with hypothyroidism are diagnosed with the condition for the first time during a fertility evaluation. A pregnant woman with hypothyroidism has a fourfold risk for miscarriage. In one study, nearly 40% of women with a history of miscarriages and normal thyroid levels had antithyroid antibodies (immune factors that attack thyroid tissue). Those who continue to have hypothyroidism near the time of delivery are in danger of developing high blood pressure and premature delivery. They are also prone to postpartum thyroiditis, which is said to be a contributor to postpartum depression.

Children of Untreated Mothers. Children born to untreated pregnant women with hypothyroidism are at risk for impaired mental performance, including attention problems and verbal impairment. Studies on the effects on children of women with subclinical hypothyroidism are less clear, with some reporting lower IQs in such children and others reporting no significant problems.

Effects of Hypothyroidism During Infancy. Transient hypothyroidism is common among premature infants. Although temporary, severe cases can cause difficulties in neurologic and mental development.

Infants born with permanent congenital (inborn) hypothyroidism need to receive treatment as soon as possible after birth to prevent mental retardation, stunted growth, and other aspects of abnormal development (a syndrome referred to as cretinism). It has been estimated that untreated infants can lose up to three to five IQ points per month during the first year. An early start of lifelong treatment avoids or minimizes this damage. Even with early treatment, however, mild problems in memory, attention, and mental processing may persist into adolescence and adulthood.

Effects of Childhood-Onset Hypothyroidism. If hypothyroidism develops in children older than 2 years, mental retardation is not a danger, but physical growth may be slowed and new teeth delayed. If treatment is delayed, adult growth could be affected. Even with treatment, some children with severe hypothyroidism may have attention problems and hyperactivity.

Two million Americans, mostly children, received x-ray treatments to the head or neck between 1920 - 1960 for acne, enlarged thymus gland, recurrent tonsillitis, or chronic ear infections. The risk of developing thyroid nodules and thyroid cancers is increased in these individuals, especially if they have hypothyroidism. Cancer can develop as late as 40 years after the original treatment. Everyone who has had head and neck radiation should be sure to have their thyroid glands examined regularly.

Treatment

Various tests are used when deciding whether to treat a patient for hypothyroidism:

First, an elevated TSH (thyrotropin) level should be confirmed and thyroxine (T4) level determined.
Testing for antithyroid antibodies and determining cholesterol levels is also important.

Treating Hypothyroidism. Patients with full-blown hypothyroidism, indicated by clear symptoms and blood tests that show high TSH (generally 10 mU/L and above) and low thyroxine (T4) levels, must be treated with thyroid replacement.

Treating Subclinical Hypothyroidism. Considerable debate exists about whether to treat patients with subclinical hypothyroidism (slightly higher than normal TSH levels, normal thyroxine levels, and no obvious symptoms). Some doctors opt for treatment because of the following benefits, although evidence remains uncertain:

Preventing progression to full-blown hypothyroidism. Treating subclinical hypothyroidism will prevent progression to overt hypothyroidism. Only a minority of people with subclinical hypothyroidism go on to develop the active condition, however.
Preventing heart disease. Some studies have shown that treating subclinical hypothyroidism lowers cholesterol levels and may improve other heart functions, including blood pressure, endothelial function, and heart rate. However, current research from 2006 suggests that subclinical hypothyroidism poses little risk for heart disease and that untreated subclinical hypothyroidism will not increase heart disease risks.
Improving well-being. Some studies report that treating subclinical hypothyroidism may improve mild psychological symptoms, such as impaired mental functioning and depression. About 25% of patients with subclinical hypothyroidism report feeling better after taking thyroid medication even if they have not previously reported symptoms.

It is not clear, then, if the benefits of treating subclinical hypothyroidism outweigh the higher costs of testing and treatments. Experts against treatment argue that thyroid levels can vary widely, and subclinical hypothyroidism may not persist. In such cases, overtreatment leading to hyperthyroidism is a real risk.

In spite of such uncertainties, three out of four major medical organizations recommend treatment for subclinical hypothyroidism, particularly in patients who have:

High total or LDL cholesterol levels
Blood tests that show autoantibodies indicating a future risk for Hashimoto's thyroiditis or other forms of other autoimmune hypothyroidism·
Blood tests that show TSH levels greater than 10 mU/L
Goiter

Experts also recommend treating subclinical hypothyroidism in:

Pregnant women
Women with infertility that may be associated with subclinical hypothyroidism

Treatment is optional in patients with subclinical hypothyroidism who have no obvious symptoms and normal cholesterol levels. If they forego treatment, however, they should be tested yearly for TSH and thyroxine.

Treating Patients with Hypothyroidism Symptom and Normal Thyroid Tests. Some doctors treat patients who have a normal or below normal thyroid function test. Some experts believe it is irresponsible to treat such patients with thyroid replacement since such symptoms can occur with many physical and psychological conditions. In any case, studies have not found any benefits from T4 replacement therapies in this group.

In the 19th century, doctors observed the relationship between myxedema (swelling of the hands, face, feet, and tissues around the eyes) and surgical removal of the thyroid gland. Some doctors began to feed patients with myxedema with whole or powdered extracts of animal thyroid glands. Using thyroid hormone to treat hypothyroidism was one of the first successful medical treatments based on careful scientific observation. With only some modifications, this approach has varied little for over a century.

A synthetic thyroid hormone called levothyroxine is currently the treatment of choice for hypothyroidism. This drug is a synthetic derivative of T4 (thyroxine), and it normalizes blood levels of TSH, T4, and T3. Nevertheless, the therapeutic principle for hypothyroidism is the same as it was more than 100 years ago: To provide the body with replacement thyroid hormone when the gland is not able to produce enough itself.

Brand Names. A number of levothyroxine brands are available in the U.S. and overseas. Synthroid is the oldest brand and has been used for over 40 years. In the past, manufacturers of levothyroxine have not had to meet as strict standards as in the production of other drugs. This resulted in thyroid products with varying quality. The FDA has issued stronger requirements that have largely corrected this problem.

Generics versus Brand-Name Products. Generic brands are available and are subject to the same guidelines as brand-name products. There is still considerable debate over whether generic thyroid preparations are as effective as brand products.

In addition, the amount of T4 in some generic products is outside the FDA range, which requires additional testing of thyroid hormone levels. Many doctors, then, prefer to use brand-name products, noting that the cost difference between brand and generic thyroid drugs is not substantial. Regardless of which type is used, once a patient has been stabilized, doctors generally recommend sticking with one type or brand since potency often varies from one drug to the next.

Natural Thyroid Hormone. Dried powdered thyroid hormone (Armour Thyroid, S-P-T, Thyrar, Thyroid Strong) is made from animal glands. It was once the most common form of thyroid therapy but is no longer generally recommended because potency varies. Some people argue that with stricter FDA regulations, this natural form is better controlled and may even reduce the risk of developing autoimmunity factors. Dried thyroid also contains both T3 and T4 and is favored as a natural treatment by many alternative practitioners. However, studies need to be conducted to evaluate its benefits.

T3 and T4 Combinations. Triiodothyronine (T3), the other important thyroid hormone, is not ordinarily prescribed except under special circumstances. Most patients respond well to thyroxine (T4) alone, which is converted in the body into T3. In addition, the use of T3 may cause disturbances in heart rhythms. Some patients treated only with thyroxine continue to have mood and memory problems or other symptoms.

Combination products containing T4 and T3, such as liotrix (Thyrolar), are available, but there is some controversy concerning their benefits. Several 2005 studies suggested that although some patients may prefer combination therapy, T3 and T4 together do not work better than T4 alone. Patients might like the combined drugs because they cause more weight loss, or a placebo effect may be involved. It does not appear that combination products offer any advantage for normalizing TSH levels.

Levothyroxine only needs to be taken once a day. It is slowly assimilated by body organs, so it usually takes up to 6 weeks before symptoms improve in adults. Nevertheless, many patients feel better after 2 - 3 weeks of treatment. The speed at which specific symptoms improve varies:

Weight loss, less puffiness, and improved pulse usually occur early in the treatment.
Improvements in anemia and skin, hair, and voice tone may take a few months.
High LDL ("bad cholesterol") levels decline very gradually. HDL ("good cholesterol") levels are not affected by treatment.
Goiter size declines very slowly, and some patients may require high-dose thyroid hormone (called suppressive thyroid therapy) for a short period.

Levothyroxine reduces blood pressure in about half of hypothyroid patients with hypertension, although blood pressure medications may still be needed.

Appropriate Dosage Levels. Initial dosage levels are determined on an individual basis and can very wide depending on a person's age, medication condition, other drugs they are taking, and, in women, whether they are pregnant or not. For example, pregnant women with hypothyroidism may require higher than normal doses.

Starting out. Most individuals need to build up gradually until they reach a maintenance dose. In uncomplicated cases, the dose typically starts at 50 micrograms per day, which then increases in 3- to 4-week intervals until thyroid hormone levels are normal. Seniors and those with heart disease may start at 12.5 - 25 micrograms per day. On the other hand, young adults with a short history of hypothyroidism might be able to tolerate a full maintenance dosage right away.
Maintenance dose. Maintenance dose for most patients averages 112 micrograms but it can vary between 75 - 260 micrograms. If conditions such as pregnancy, surgery, or other drugs alter hormone levels, the patient's thyroid needs will have to be reassessed.

Daily Regimen. Because thyroid replacement is usually lifelong, setting up a regular daily routine is helpful. Here are some tips to remember:

Establish a habit of taking the medication at the same time each day. This may help prevent missed doses.
Levothyroxine is very forgiving. The hormone remains in the body for several days, so one missed dose should not cause a noticeable decline in well-being. The patient can safely take two doses the next day.
Fiber and common daily supplements, such as calcium, may interfere with thyroxine absorption. Although levothyroxine can be taken at any time of day either with or without food, some experts recommend taking thyroid hormone upon awakening and at least 30 minutes before consuming anything, including breakfast or supplements.

Annual Evaluation. Thyroid failure is an ongoing process and so is its treatment. Many factors can cause changes that require modifying the thyroxine dosages.

A dose that is appropriate for 1 year may be too low the next. To maintain normal thyroid levels, some patients may need to take gradually increasing doses of thyroid hormone every year or two. Experts recommend that patients be reevaluated 6 months after normal TSH levels have been reached and then once a year thereafter.

Specific factors, such as changes in health or diet, new medications for other conditions, or simply switching brands, can also cause changes in thyroid hormone levels that require different doses. If patients change dose levels or thyroxine brands then they should be checked again at least 6 weeks later.

Because levothyroxine is identical to the thyroxine the body manufactures, side effects are rare. Over- or under-dosing, however, is fairly common, although rarely serious in the short term.


Under-Dosing	Over-Dosing
Sluggishness	Heart symptoms (rapid heart beat, palpitations, and wide variations in pulse; possible angina or congestive heart failure)
Mental dullness	Agitation (tremor, nervousness, insomnia, excessive sweating)
Feeling cold	Pain (headache and muscle pain)
Muscle cramps	Intestinal and metabolic symptoms (change in appetite, diarrhea, weight loss)
	Fever and intolerance to heat

No Symptom Improvement When Normal Thyroid Levels Are Reached. Some patients fail to feel significantly better even when their thyroid levels become normal after taking thyroid replacement.

Some experts argue that many patients become symptom-free only if their thyroid replacement achieves high-normal T4 and low-normal TSH levels (rather than just normal levels). They believe that slightly higher thyroxine levels will not be harmful. Research is needed to confirm these claims.

Some patients with persistent symptoms may benefit from triiodothyronine (T3), the other important thyroid hormone. In such cases, either a combination of a lower-dose of thyroxine with a small amount of T3 or natural dried thyroid hormone, which contains T3, may be helpful.

Side Effects of Under-Dosing. If the levothyroxine dose is not sufficient to restore normal thyroid levels, or if the patient frequently forgets to take the medication, the patient may continue to experience symptoms of hypothyroidism. Even mild hypothyroidism without any symptoms can eventually lead to an increase in cholesterol levels. In a 2000 study, 40% of people taking thyroid medication still had abnormal levels of TSH. To avoid these problems, patients should take the proper dosage of levothyroxine as prescribed and have regular check-ups that include measurement of blood TSH.

Side Effects of Over-dosing: Thyrotoxicosis. Over-dosing can cause thyrotoxicosis, or the symptoms of hyperthyroidism. A patient with too much thyroid hormone in the blood is at an increased risk for abnormal heart rhythms, rapid heartbeat, congestive heart failure, and possibly a heart attack if the patient has underlying heart disease. Excess thyroid hormone is particularly dangerous in newborns, and their drug levels must be carefully monitored to avoid brain damage.

Side Effects of Long-Term Treatment. Patients with hypothyroidism usually receive lifelong levothyroxine therapy. There has been some concern that long-term use will increase the risk of osteoporosis, as suppression therapy does. Studies indicate that postmenopausal women who are taking long-term normal replacement thyroxine have no out-of-the-ordinary risk for osteoporosis.

Drug Interactions with Levothyroxine. Many drugs interact with levothyroxine and may either enhance or interfere with its absorption. These drugs include amphetamines, anticoagulants (blood thinners), tricyclic antidepressants, anti-anxiety drugs, arthritis medications, aspirin, beta-blockers, insulin, oral contraceptives, digoxin, and certain cancer drugs. Large amounts of dietary fiber may also reduce the drug’s effectiveness. People whose diets are consistently high in fiber may require larger doses of the drug. Since thyroid hormones regulate the metabolism and can affect the actions of a number of medications, dosages may also need to be adjusted if a patient is being treated for other conditions. Even changing thyroxine brands can have a different effect.

Suppressive thyroid therapy involves taking levothyroxine in doses that are high enough to block the production of natural TSH but too low to cause hyperthyroid symptoms. It may used for patients with large goiters or thyroid cancer.

Suppressive thyroid therapy places patients, particularly postmenopausal women, at risk for accelerated osteoporosis, a disease that reduces bone mass and increases risk of fractures. Some researchers suggest, however, that such bone loss is too slight to pose any significant risk for fracture. Furthermore, the cholesterol-lowering benefits of suppressive therapy outweigh this small risk. A small study found that premenopausal women taking suppressive therapy for more than 10 years were also at increased risk of bone loss by the time they reach menopause, although more research is needed to confirm this.

Bone density loss can be reduced or avoided by taking no higher a dose of thyroxine than necessary to restore normal thyroid function. In any case, doses of T4 must be continuously and carefully tailored in all patients to avoid adverse effects on the heart.

A number of medications are also available that can help preserve bone in postmenopausal women. Women on hormone replacement therapy may need to increase their dose of thyroid hormone.

Drugs that Inhibit Thyroid Hormone

Drugs that are Enhanced by Thyroid Hormone

Drugs that are Suppressed by Thyroid Hormone

Drugs that Reduce Natural Thyroid Hormone Levels and May Cause Hypothyroidism

Iron supplements (even low doses found in multivitamins)

Calcium carbonate supplements

Aluminum-containing antacids (Maalox)

Drugs used to reduce cholesterol levels by binding bile acids (colestipol and cholestyramine)

Estrogens in oral contraceptives and hormone replacement therapy (may need to increase thyroid hormone while taking estrogen)

Raloxifene (Evista), a designer-estrogen used for osteoporosis

Sucralfate (Carafate)

Epinephrine (adrenaline) injections. Thyroid hormone may increase the risk of serious side effects in heart disease patients given this drug.

Warfarin, a blood thinner. Doses of this medication may need to be reduced if thyroid treatment is started after blood thinning treatments have begun.

Many antidepressants. In some cases, potency of both antidepressants and thyroid hormones may increase.

Diabetes drugs. Patients taking thyroid hormone may need additional insulin or oral hypoglycemic drugs. Stopping or reducing thyroid hormone may increase the risk of low blood sugar.

Digoxin. Patients with heart disease may need to increase their dosage of digoxin.

Lithium. This drug, used for bipolar disorder, has multiple effects on thyroid hormone synthesis and secretion.

Amiodarone (Cordarone). This drug, used to treat abnormal heart rhythms, contains iodine and can induce hyper- or hypothyroidism, particularly in patients with an existing thyroid problem.

Antiseizure drugs used for epilepsy, including phenytoin and carbamazepine.

Interferons and interleukins used in hepatitis, multiple sclerosis, and other conditions.

Rifampin, used for tuberculosis.

Some drugs used for cancer chemotherapy.

Interferon.

Large doses of selenium, a dietary supplement.

Treating the Elderly and Patients with Heart Disease. Thyroid dysfunction is common in elderly patients, with most having subclinical hypothyroidism. There is no evidence that this condition poses any great harm in this population, and some experts recommend treating only high-risk patients. One study suggested many elderly patients have been treated unnecessarily for hypothyroidism for years. In the study, half the patients taking thyroid hormone were taken off the medication successfully. Such patients may have been inappropriately diagnosed years ago, when testing was less accurate. More sensitive tests available now should reduce this risk.

Elderly patients, particularly people with heart conditions, usually start with lower doses of thyroid replacement, since a large initial dose may be a shock to the heart. Thyroid treatment may aggravate angina in about 20% of patients with the heart condition. About 40% of patients who have heart disease must take lower-than-average maintenance doses. Experts do not recommend treatment for subclinical hypothyroidism in elderly patients with heart disease whose test show only minimal thyroid hormone abnormalities and who have no anti-thyroid antibodies. Such patients should be closely monitored, however.

Preliminary research indicates that in patients undergoing cardiac bypass surgery, administration of triiodothyronine at the time of surgery may improve blood flow, heart rate, and cardiac output. Patients with advanced heart failure may also benefit from supplementary thyroid hormone.

Treating the Mentally Ill. Patients with psychiatric illness often forget to take their medications regularly. In these patients, once- or twice-weekly dosing of thyroid medications is often safe and effective and may improve compliance.

Treating Newborns and Infants with Hypothyroidism. Babies who are born with hypothyroidism (congenital hypothyroidism) should be treated with levothyroxine (T4) as soon as possible to prevent complications. Early treatment can help improve IQ and other developmental factors. However, even with early treatment, mild problems in mental functioning may persist into adulthood. In general, children who are born with milder forms of hypothyroidism will fare better than those who have more severe forms.

Single oral doses of levothyroxine (T4) can usually restore normal thyroid hormone levels within 1 - 2 weeks. It is critical that normal levels are achieved within a 2-week period. If thyroid function is not normalized within 2 weeks, it can pose greater risks for developmental problems. Some experts urge treating newborns at slightly higher than recommended doses for the first 2 weeks and then reducing the dosage once normal thyroid levels have been reached. Infants should continue to be monitored closely to be sure that thyroxine levels remain as consistently close to normal as possible. These children need to continue lifelong thyroid hormone treatments.

Treatment During Pregnancy and for Postpartum Thyroiditis. Women who have hypothyroidism before becoming pregnant may need to increase their dose of levothyroxine during pregnancy. In very rare cases, women may develop hypothyroidism while pregnant and need to be treated with levothyroxine in full replacement doses to reduce the risk of stillbirth. The developing baby is not affected when the pregnant woman takes thyroid hormones. The pregnant woman with hypothyroidism should be monitored regularly and doses adjusted as necessary. If postpartum thyroiditis develops after delivery, any thyroid medication should be reduced or temporarily stopped during this period.

Treatment for Myxedema Coma. Myxedema coma is an emergency situation, and the patient should be given intravenous doses of thyroid hormone, which could be triiodothyronine, levothyroxine, or both. Lower doses may be safer in elderly patients. Oftentimes, hydrocortisone, a corticosteroid, is also administered. Any other accompanying critical condition, including low body temperature, slow heart rate, low blood sugar, and difficulty in breathing, should also be treated immediately.

Treatment of Secondary Hypothyroidism. The small percentage of patients who have hypothyroidism due to a pituitary or hypothalamus problem should take levothyroxine along with their other medication to treat the primary disorder. In secondary hypothyroidism, the adrenal gland is often impaired. This means that the increased activity in the metabolic rate that occurs after thyroid replacement therapy may trigger a severe and even life-threatening condition called addisonian crisis, which is caused by a sudden demand for the depleted stress hormones secreted by the adrenal gland. Before administering thyroid replacement, the doctor should initiate a test that stimulates release of ACTH, one of the hormones secreted by the adrenal gland. If there is insufficient ACTH, then before thyroid replacement is started, the patient is usually treated with cortisone acetate, a stress hormone.

In one study of those taking thyroid hormone, 12% of women and 29% of men took it inappropriately. In some cases of infertility, women with menstrual problems and repeated miscarriages and men with low sperm counts have been treated with thyroid hormones even when there was no evidence of thyroid abnormalities. (Women showing high levels of TSH, however, may benefit from levothyroxine therapy.)

Other inappropriate uses for thyroid hormones are for weight loss and to reduce high cholesterol levels. Thyroid hormones have also been given to treat so-called metabolic insufficiency. Vague symptoms suggesting low metabolism, such as dry skin, fatigue, slight anemia, constipation, depression, and apathy, should not be treated indiscriminately with thyroid hormone. No evidence exists that thyroid therapy is beneficial unless the patient has proven hypothyroidism. Indiscriminate use of thyroid hormones can weaken muscles and, over the long term, even the heart. One exception is the use of thyroxine to enhance drugs used for the treatment of severe depression.

Treating Hypothyroidism and Iodide Deficiency. People who are iodide deficient may be able to be treated for hypothyroidism simply by using iodized salt. In addition to iodized salt, seafood is a good source. Except for plants grown in iodine-rich soil, most other foods do not contain iodine. The current RDA for iodide is 150 micrograms for both men and women, with an upper limit of 1,100 micrograms to avoid thyroid injury.

Iodine Restriction in Patients with Hashimoto's Thyroiditis. Some evidence suggests that excess iodine triggers Hashimoto's thyroiditis. Small studies report that restricting iodine intake restored thyroid levels to normal in up to 75% of these patients. More research is needed.

Resources

www.aace.com -- American Association of Clinical Endocrinologists
www.thyroid.org -- American Thyroid Association
www.tsh.org -- Thyroid Foundation of America
www.endo-society.org -- Endocrine Society

References

Desai J, Yassa L, Marqusee E, George S, Frates MC, Chen MH, et al. Hypothyroidism after sunitinib treatment for patients with gastrointestinal stromal tumors. Ann Intern Med. 2006 Nov 7;145(9):660-4.

Roberts LM, Pattison H, Roalfe A, Franklyn J, Wilson S, Hobbs FD, et al. Is subclinical thyroid dysfunction in the elderly associated with depression or cognitive dysfunction? Ann Intern Med. 2006 Oct 17;145(:573-81.

Roos A, Bakker SJ, Links TP, Gans RO, Wolffenbuttel BH. Thyroid function is associated with components of the metabolic syndrome in euthyroid subjects. J Clin Endocrinol Metab. 2007 Feb;92(2):491-6.

Review Date:
3/20/2007
Reviewed By:
Harvey Simon, MD, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital.

A.D.A.M. Copyright

adam.com

Cholesterol

FitSugar — Wed, 08 Oct 2008 17:34:59 -0700

In This Report

Highlights
Introduction
Cholesterol's Effect on the...
Cholesterol's Effect on the...
Risk Factors
Symptoms
Diagnosis
Lifestyle Changes
Treatment
Resources
References

HEALTH GUIDE REFERENCE FROM A.D.A.M

Highlights

New Guidelines for Children and Adolescents

In 2007, the American Heart Association (AHA) established new guidelines for assessing and treating high cholesterol in children and adolescents. According to the AHA’s scientific statement:

LDL (“bad") cholesterol goals for children should be 190 mg/dL or less for children without heart disease risk factors and 160 mg/dL or less for children with heart disease risk factors.
Children who are overweight or obese, as well as those with a family history of high cholesterol and heart disease, should get their cholesterol levels checked.
For overweight and obese children with cholesterol imbalances, diet changes and exercise should be tried before drug treatment. For children with cholesterol imbalances who have a family history of cholesterol and heart problems, statins are the best first-line drug therapy.

Herbs and Supplements

Garlic, whether raw or in supplement form, does not help lower LDL in patients with moderately high LDL levels, according to a 2007 Archives of Internal Medicine Study.
Policosanol, a dietary supplement derived from sugar cane, has no effect on cholesterol, indicates a 2006 Journal of the American Medical Association (JAMA) study.

Diet Plans

In a 2007 JAMA comparison study of four diet plans (Atkins, Ornish, Zone, and LEARN), the low-carbohydrate Atkins diet was best at raising HDL (“good cholesterol”) levels and lowering triglyceride levels, but did not affect LDL levels. The low-fat Ornish diet was best at lowering LDL levels.
The Mediterranean diet works better than a low-fat diet in quickly lowering cholesterol as well as blood pressure and blood sugar, suggests a 2006 Annals of Internal Medicine study.

Drug Research

In contrast to research findings released last year, rosuvastatin (Crestor) does not appear to reverse heart disease, according to a 2007 JAMA study. However, the statin drug did help slow the progression of arterial thickening.

Introduction

Lipids are the building blocks of the fats and fatty substances found in animals and plants. They are microscopic layered spheres of oil, which, in animals, are composed mainly of cholesterol, triglycerides, proteins (called lipoproteins), and phospholipids (molecules made up of phosphoric acid, fatty acids, and nitrogen). Lipids do not dissolve in water and are stored in the body to serve as sources of energy.

Cholesterol is a white, powdery substance that is found in all animal cells and in animal-based foods (not in plants). In spite of its bad press, cholesterol is an essential nutrient necessary for many functions, including:

Repairing cell membranes
Manufacturing vitamin D on the skin's surface
Producing hormones, such as estrogen and testosterone
Possibly helping cell connections in the brain that are important for learning and memory

Regardless of these benefits, when cholesterol levels rise in the blood, they can have dangerous consequences, depending on the type of cholesterol. Although the body acquires some cholesterol through diet, about two-thirds is manufactured in the liver, its production stimulated by saturated fat. Saturated fats are found in animal products, meat, and dairy products.

Saturated fats are found predominantly in animal products, such as meat and dairy products, and are strongly associated with higher cholesterol levels. Tropical oils -- such as palm, coconut, and coconut butter -- are also high in saturated fats.

Triglycerides are composed of fatty acid molecules. They are the basic chemicals contained in fats in both animals and plants.

Lipoproteins are protein spheres that transport cholesterol, triglyceride, or other lipid molecules through the bloodstream. Most of the information about the effects of cholesterol and triglyceride actually concerns lipoproteins.

Lipoproteins are categorized into five types according to size and density. They can be further defined by whether they carry cholesterol or triglycerides.

Cholesterol-Carrying Lipoproteins. These are the lipoproteins commonly referred to as cholesterol.

Low density lipoproteins (LDL). (Often called the "bad" cholesterol.)
High-density lipoproteins (HDL), the smallest and most dense. (Referred to as the "good" cholesterol.)

Triglyceride-Carrying Lipoproteins.

Intermediate density lipoproteins (IDL). They tend to carry triglycerides.
Very low density lipoproteins (VLDL). These tend to carry triglycerides.
Chylomicrons (largest in size and lowest in density).

Lipoprotein(a). Lipoprotein(a), or lp(a) has a size and density somewhere between LDL and HDL. The molecules carry a protein that may interfere with the body's ability to dissolve blood clots. Lipoprotein(a) is being investigated as a possible marker or cause of heart disease.

Remnant Lipoproteins. Remnant lipoproteins are byproducts of chylomicrons, very low-density lipoproteins (VLDL), or both. Some research indicates that high levels may be an important risk factor for coronary artery disease, particularly in patients who have otherwise normal cholesterol levels.

Reducing LDL and total cholesterol levels, while at the same time boosting HDL levels, can prevent heart attacks and death in all people (with or without heart disease). Reducing LDL is the primary goal of most cholesterol therapy.

Blood tests can easily measure both HDL and overall cholesterol levels. It is very difficult to measure LDL levels by themselves, but LDL levels can be reliably calculated by subtracting HDL and triglyceride levels from total cholesterol. The exact formula is:

LDL = TOTAL CHOLESTEROL - HDL - TRIGLYCERIDES/5.

In 2004, the National Cholesterol Education Program updated its clinical practice guidelines. The new recommendations set lower treatment goals for LDL levels based on a patient's risk factors for heart disease.

The risk factors include:

Having a first-degree female relative diagnosed with heart disease before age 65 or a first-degree male relative diagnosed before age 55
Being male and over age 45 or female and over age 55
Cigarette smoking
Diabetes
High blood pressure
Metabolic syndrome (risk factors associated with obesity such as low HDL levels and high triglycerides)

Two or more of these risk factors increases by 20% the chance of having a heart attack within 10 years.

The LDL cholesterol level is one of the most important factors in determining whether a patient needs cholesterol therapy and whether the treatment is working properly. In particular, the new guidelines emphasize lower LDL levels and earlier treatment for people with coronary artery disease, or other forms of atherosclerosis, and diabetes.


Risk Level	Goal (d/L)	OptimalGoal(d/L)
Very High Risk	70	70
High Risk	100	70
Moderate Risk	130	100
Low Risk	160	130

The following chart summarizes all goals.


Total Cholesterol Goals	LDL Goals	HDL Goals	Triglyceride Goals
Less than 200 mg/dL is desirable. Between 200 and 239 is borderline. Over 240 is high.	70 mg/dL is the new goal for very high-risk patients (recent heart attack; current active or unstable cardiovascular or cerebrovascular disease; or two multiple risk factors as defined above.) Below 100 mg/dL is optimal for everyone. It should be the goal for high-risk people including those with existing heart disease, diabetes, or two or more risk factors for heart disease; 70 mg/dL is an optimal goal for these individuals. 130 mg/dL or below for people with two or more risk factors; 100 mg/dL is an optimal goal. 160 mg/dL or below for people at less risk (one or zero risk factors); 130 mg/dL is an optimal goal. Anything above 160 is high, with levels above 190 being very high. LDL levels over 190 require medication even with no other cardiac risk factors present.	Levels above 40 mg/dL are desirable; levels above 60 mg/dL are optimal.	Below 150 mg/dL is normal. 150 - 199 is borderline high. 200 - 499 is high. Over 500 is very high.
*Risk factors for heart disease include a family history of early heart problems before age 55 for men (before age 65 for women), smoking, high blood pressure, diabetes, being older (over 45 for men and 55 for women), and having HDL levels below 35 mg/dL. People with two or more of these risk factors may have a 10-year risk of heart attack that exceeds 20%, and may therefore need to aim for LDL levels of 100 mg/dL or below.

Although current guidelines as described in the table are extremely useful, they do have pitfalls. For example, the following cholesterol levels pose some dilemmas:

Low LDL levels (protective) accompanied by low HDL, high triglycerides, or both (harmful)
High total cholesterol (harmful) accompanied by high HDL (protective)

Would individuals with these cholesterol balances be at high risk or low risk for developing heart disease? To resolve this dilemma, experts have devised a calculation for a risk ratio by dividing the total cholesterol by either total HDL or LDL. It is not clear at this point which ratio is a better predictor of heart disease, although the HDL ratio may be superior. Using this ratio, the following results indicate better to worse outlook:

The ideal ratio is 3.5 or below.
A ratio of 4.5 carries an average risk.
Ratios of 5 or higher are potentially dangerous.

For example, if a person has a high total cholesterol of 280 mg/dL but a high HDL level of 70 mg/dL, the risk ratio is 4, which actually carries a lower than average risk. The use of this ratio may predict coronary artery disease more accurately than using total cholesterol levels alone. Still, the primary goal of lipid-lowering therapy is reducing LDL levels. Evidence strongly suggests that the lower the LDL levels, the lower the risk for heart disease.

Cholesterol's Effect on the Heart

Coronary artery disease, commonly known as heart disease, is the leading cause of death in the U.S. and was responsible for nearly 500,000 deaths in 2003.

Atherosclerosis is a common disorder of the arteries. Fat, cholesterol, and other substances collect in the walls of arteries. Larger accumulations are called atheromas or plaque and can damage artery walls and block blood flow. Severely restricted blood flow in the heart muscle leads to symptoms such as chest pain.

As many as half of these deaths were probably due to unhealthy cholesterol and lipid levels. Strong evidence points to LDL as the villain and HDL as a hero in the process. The role of other lipids, notably triglycerides, is not entirely clear.

Unhealthy cholesterol, particularly low-density lipoprotein (LDL), forms a fatty substance called plaque, which builds up on the arterial walls. Smaller plaques remain soft, but older, larger plaques tend to develop fibrous caps with calcium deposits.

Click the icon to see an image of the developmental process of atherosclerosis.

The long-term result is atherosclerosis, commonly called hardening of the arteries. The heart is endangered in two ways by this process:

Eventually these calcified and inelastic arteries become narrower (a condition known as stenosis). As this process continues, blood flow slows and prevents sufficient oxygen-rich blood from reaching the heart. This condition leads to angina (chest pain) and, in severe cases, to heart attack.

Click the icon to see an image of a heart attack.

Smaller unstable plaques may rupture, triggering the formation blood clots on their surface. The blood clots block the arteries and are important causes of heart attack.

This process is accelerated and enhanced by other risk factors, including high blood pressure, smoking, obesity, diabetes, and a sedentary life style. When more than one of these risk factors is present, the risk is compounded.

The effects of cholesterol on the heart may involve more than just the arteries. There is some evidence that unhealthy levels may affect the heart muscles and increase the risk for heart failure. High cholesterol levels may even reduce the protection that aspirin provides for people with heart disease.

On an encouraging note, mortality rates associated with coronary artery disease have declined dramatically during the past 30 years. Some experts estimate that about 30% of the decline is due to better cholesterol management and statin drugs.

Studies consistently report a higher risk for death from heart disease with high total cholesterol levels (200 mg/dL and higher). The higher the cholesterol, the greater the risk. One study reported that men with total cholesterol levels higher than 240 mg/dL had a risk nearly two to four times that of men whose cholesterol was below 200 mg/dL. On average, every time a person's cholesterol level drops by a point, the risk of heart disease drops by 2%.

The primary villain in the cholesterol story is low-density lipoprotein (LDL). In a major study, the lowest incidence in heart disease was found among people with the lowest LDL levels. Lowering LDL is the primary goal of cholesterol drug and lifestyle therapy.

Low-density lipoprotein (LDL) transports about 75% of the blood's cholesterol to the body's cells. It is normally harmless. However, if it is exposed to a process called oxidation, LDL can penetrate and interact dangerously with the walls of the artery, producing a harmful inflammatory response. Oxidation is a natural process in the body that occurs from chemical combinations with unstable molecules. These molecules are known as oxygen-free radicals or oxidants.

When LDL collects on arterial walls these oxidants are released from the wall membranes.
Oxidants are missing an electron and tend to bind with other molecules in the body, a process called oxidation.
When the oxidation process modifies LDL, it signals the immune system that a harmful molecule has appeared.

Inflammation and Plaque. In response to oxidized LDL, the body releases various immune factors aimed at protecting the damaged walls. Unfortunately, in excessive quantities they cause inflammation and promote further injury to the areas they target:

White blood cells and other factors gather and form a fatty substance called plaque. (Of interest in this process is an enzyme called lipoprotein-associated phospholipase A2, which binds to oxidized LDL. Studies report that this enzyme may play a major role in the release of plaque-forming inflammatory factors.)
Other immune factors also cause inflammation and injure the endothelium, the layer of cells that line blood vessels.

Click the icon to see an image of the cut section of an artery.

Immune factors that increase the risk for blood clots are also mobilized.
Oxidized LDL plays another dangerous role by reducing levels of nitric oxide, a chemical that helps relax the blood vessels and allow blood to flow freely.

High density lipoprotein (HDL) appears to benefit the body in two ways:

It removes cholesterol from the walls of the arteries and returns it to the liver.

Click the icon to see an image of the liver.

It helps prevent oxidation of LDL. HDL actually appears to have its own antioxidant properties.

HDL helps keep arteries open and reduces the risk for heart attack. High levels of high HDL (above 60 mg/dL) may be nearly as important for the heart as low levels of LDL. HDL levels below 40 mg/dL are considered to be harmful. In one study, for each 4 mg/dL decline in HDL levels there was a 10% increase in coronary artery disease.

Triglycerides are major troublemakers for the heart. They appear to interact with HDL cholesterol in such a way that HDL levels fall as triglyceride levels rise. Low HDL is known to be harmful to the heart.

The harmful imbalance of high triglycerides with low HDL levels is also associated with obesity (particularly around the abdomen), insulin resistance, and diabetes. Insulin is a hormone essential for regulating the storage and use of glucose (sugar) and amino acids (proteins) in the body. Insulin resistance occurs when there are normal levels of insulin but the body cannot use it. Insulin resistance increases the risk for developing type 2 diabetes, and it is also associated with metabolic syndrome. Both of these conditions increase the risk for heart disease.

Some evidence also suggests that high triglycerides pose other dangers, regardless of cholesterol levels. Triglycerides, for example, may be responsible for blood clots that form and block the arteries. High triglyceride levels are also associated with the inflammatory response -- the harmful effect of an overactive immune system that can cause considerable damage to cells and tissues, including the arteries.

Studies are finding an elevated risk for angina and first heart attacks in people with elevated levels of lipoprotein(a), also known as or lp(a). This lipoprotein falls somewhere between HDL and LDL in density and may have some properties that increase the risk for blood clots. Some experts suggest, however, that high levels of lp(a) may merely be markers of late-stage atherosclerosis, not a cause. Because concentrations of lipoprotein(a) are usually inherited, they do not respond to dietary or lifestyle changes. At this time, few experts recommend drug treatments to reduce lp(a) levels. Older women, but not men, appear to be at greater risk for high lp(a) levels and their consequences.

Cholesterol's Effect on the Brain

Having adequate levels of HDL may be the most important lipid-related factor for preventing ischemic stroke, a type of stroke caused by blockage of the carotid arteries that carry blood to the brain. HDL may even reduce the risk for hemorrhagic stroke, a less common type of stroke caused by bleeding in the brain that is associated with low overall cholesterol levels.

The build-up of plaque in the internal carotid artery may lead to narrowing and irregularity of the artery's lumen, preventing proper blood flow to the brain. More commonly, as the narrowing worsens, pieces of plaque in the internal carotid artery can break free, travel to the brain, and block blood vessels that supply blood to the brain. This leads to stroke, with possible paralysis or other deficits.

The effects of high total cholesterol and LDL levels on ischemic stroke are less clear. One study suggested that the risk for ischemic stroke increases when total cholesterol is above 280 mg/dL. A 2002 study suggested that high cholesterol poses a risk for stroke only when specific proteins associated with inflammation are present.

Evidence points to high cholesterol levels, along with high blood pressure and a family history of the disease, as independent risk factors for AD. A major research target for common factors between cholesterol levels and AD has been apolipoprotein E (ApoE). ApoE plays a role in the movement and distribution of cholesterol for repairing nerve cells during development and after injury. People who carry a variant of this gene (ApoE4) are at significantly higher risk for AD.

High cholesterol may pose a risk for Alzheimer's regardless of this genetic factor, however. Some studies report that cholesterol is important within the brain for cell communication and memory.

Risk Factors

About half of all American adults have total cholesterol levels over 200 mg/dL. Over 25% have been told by doctors that they have unhealthy levels. Total cholesterol levels have been declining over the last several decades, at least among middle-aged and older adults. This decline may be partly due to the increased use of statins and other lipid-lowering medications. However, total cholesterol levels are getting higher among younger adults (ages 25 – 34 years). The major risk factor for these high rates may be the Western lifestyle. The typical high-fat/low-fiber American diet coupled with sedentary habits is largely responsible for this unfortunate trend.

Men. Heart disease is the major cause of death in men. On average, men develop coronary artery disease 10 - 15 years earlier than women do and have a greater risk for dying of heart disease at a younger age. A 2006 study suggested that high total cholesterol may also contribute to the development of high blood pressure in men.

Women. Coronary artery disease is also the number one killer of women. Women between the ages of 20 and 34, and after menopause (around age 55), have higher cholesterol levels than men. Some evidence suggests that HDL levels may be more significant in women than in men. In one study, at total cholesterol levels above 200, women with HDL levels below 50 had a higher death rate than those with levels above 50, regardless of their LDL cholesterol levels. Women also appear to be more susceptible to the high-triglyceride low-HDL syndrome, which may be a particular risk factor for heart disease.

Children and Adolescents. Children who have abnormal cholesterol levels are at increased risk of developing heart disease later in life. However, it is difficult to distinguish “normal” cholesterol levels in children. Changes in cholesterol levels occur between the ages of 8 - 18, and vary between genders and population groups. Cholesterol levels tend to naturally rise sharply until puberty, then decrease sharply, and then rise again.

In 2007, the American Heart Association established general LDL goals for children that take into account these fluctuations. The association’s LDL goals are 190 mg/dL or less for children with no additional heart disease risk factors and 160 mg/dL or less for children with additional risk factors (such as family history of high cholesterol, heart disease, and diabetes).

It is also clear that children who are overweight are at higher risk for high triglycerides and low HDL, which may be directly related to later unhealthy cholesterol levels. Studies have confirmed that childhood LDL levels and body-mass index (BMI) are strongly associated with cardiovascular risk during adulthood. The American Heart Association recommends that children who are overweight and obese, as well as those with a family history of high cholesterol, undergo cholesterol screening. Overweight and obese children who have high cholesterol should also get tested for high blood pressure, diabetes, and other conditions associated with metabolic syndrome.

As in adults, the primary source of unhealthy cholesterol levels in children comes from diets high in unhealthy fats: Saturated fats (found mainly in animal and dairy products) and trans fatty acids (found in commercial food products). Over-consumption of unhealthy fats increases the risk for both obesity and heart disease.

Less common causes of unhealthy cholesterol levels in children include:

Low-birth weight (associated with low HDL levels)
Low thyroid levels (hypothyroidism)
Kidney or liver diseases
Homozygous familial hypercholesterolemia. This is an uncommon inherited condition that causes severe cholesterol imbalances and can result in very early heart disease.
Certain medications such as specific antiseizure drugs, corticosteroids, and isotretinoin (Accutane)

Young and Middle-Aged Adults. The strongest evidence of unhealthy cholesterol levels and heart disease is in adults over age 45. However, a 2006 analysis found that while total cholesterol levels are decreasing among older adults, they are increasing in those age 25 - 34 years. Research strongly suggests that the younger a person is when unhealthy cholesterol levels develop, the greater the chance for serious heart and blood vessel problems in the future. A 2006 study in the New England Journal of Medicine indicated that keeping LDL levels low from an early age can help prevent heart disease later in life. In one important study, young men (ages 16 - 34) who had cholesterol levels at or above 240 mg/dL had two to four times the risk of dying from heart attack or other cardiac problems than did men whose cholesterol was lower than 200 mg/dL. Young men without cholesterol problems had a higher life expectancy, by up to 8 years. Other studies have suggested similar risks from unhealthy cholesterol in young women as well.

Elderly Adults. About 85% of people who die from coronary artery disease are over the age of 65. Because high cholesterol is an important risk factor for heart disease, experts strongly recommend statin or other lipid-lowering therapy for elderly people with high cholesterol levels. Surveys indicate that total cholesterol levels have been declining in older people over the last few decades. Many experts believe this is due in part to increased use of statin drugs.

In the U.S., obesity is at epidemic levels in all age groups. The effect of obesity on cholesterol levels is complex. Although obesity does not appear to be strongly associated with overall cholesterol levels, obese individuals tend to have high triglyceride levels and low HDL levels. This combination is a risk factor for heart disease. Obesity also causes other effects (high blood pressure, increase in inflammation) that pose major risks to the heart.

Obesity is a particularly hazard when it is one of the components of the metabolic syndrome, formerly known as syndrome X. This syndrome consists of obesity marked by abdominal fat, unhealthy cholesterol levels, high blood pressure, and insulin resistance. Metabolic syndrome is a pre-diabetic condition that is significantly associated with heart disease and higher mortality rates from all causes. A 2002 study estimated that 24% of the population now has this condition. Many experts recommend that patients with metabolic syndrome should be aggressively treated with high-dose statin therapy to lower LDL levels.

Obesity is also strongly associated with type 2 diabetes, which itself poses a significant risk for high cholesterol levels and heart disease.

Low thyroid levels (hypothyroidism) are associated with unhealthy lipid levels. (Lipids are fat molecules). Specifically, people with hypothyroidism are at higher risk for high total and LDL cholesterol, triglycerides, and other lipids associated with heart disease. Treating the thyroid condition can significantly reduce cholesterol levels. Some experts suggest that patients with high cholesterol should be evaluated for thyroid function before they are given cholesterol-lowering drugs. Research is mixed on whether mild hypothyroidism (subclinical hypothyroidism) is associated with unhealthy cholesterol levels. [See In-Depth Report #38: Hypothyroidism.]

Hypothyroidism is a decreased activity of the thyroid gland which may affect all body functions. In this condition, the rate of metabolism slows, causing mental and physical sluggishness. The most severe form of hypothyroidism is myxedema, which is a medical emergency.

Genetics play a major role in determining a person's blood cholesterol levels. Children from families with a history of premature heart disease should be tested for cholesterol levels after they are 2 years old. Genes may influence whether a person has low HDL levels, high LDL levels, high triglycerides, or high levels of other lipoproteins, such as lipoprotein(a).

Some inherited disorders and genetic abnormalities have been identified:

Familial hypercholesterolemia causes dangerous increases in cholesterol. It may be more common than previously thought. One European study reported familial hypercholesterolemia in 1 out of every 400 people.
Familial lipoprotein lipase deficiency is a very rare disorder that causes depletion of lipoprotein lipase. This is an enzyme that appears to be important in the removal of lipoproteins that are rich in triglycerides. People who are deficient in it have high levels of cholesterol and fat in their blood. A very low-fat diet is essential and is an effective treatment for these individuals.
Several studies have found a genetic mutation affecting neuropeptide Y in people with high total cholesterol and LDL levels. Neuropeptide Y is a compound in the brain that regulates appetite.
Researchers have identified a gene called APOAV, which may help detect patients at risk for elevated levels of triglycerides.

Other medical conditions strongly associated with unhealthy cholesterol levels include:

Polycystic ovarian syndrome. Women with this disorder, particularly those who are obese, appear to be at increased risk for high triglyceride and low HDL levels. This risk may be due to higher levels of the male hormone testosterone in these women.

Click the icon to see an image of a polycystic ovary.

Kidney disease

Symptoms

There are no warning signs for high LDL cholesterol levels. When symptoms finally occur, they usually take the form of angina or heart attack in response to the buildup of atherosclerotic plaque in the patient's arteries. This is definitely a condition where it pays to invest in preventive medicine before dangerous complications occur.

Atherosclerosis is a disease of the arteries in which fatty material is deposited in the vessel wall, resulting in narrowing and eventual impairment of blood flow. Severely restricted blood flow in the arteries to the heart muscle leads to symptoms such as chest pain. Atherosclerosis shows no symptoms until a complication occurs.

Diagnosis

A blood test for cholesterol should include the entire lipoprotein profile: LDL, total cholesterol, HDL, and triglycerides. It is very difficult to measure LDL levels by themselves, but LDL levels can be reliably calculated using total cholesterol and HDL levels.

To obtain a reliable cholesterol reading, experts advise:

Avoid strenuous exercise for 24 hours before the test.
Do not eat or drink anything but water for 12 hours beforehand.
If the test results are abnormal, a second test should be performed between 1 week and 2 months after the first test.

Home Tests. Tests are available for home use and in public locations, such as shopping malls and pharmacies. For example, the CholesTrak Test can be taken at home with results in 10 minutes, but it measures only total cholesterol. The BioSafe Cholesterol Panel Test is also a home test, but it needs to be sent to a laboratory. This test, however, is very accurate and provides a full lipid profile.

Certain blood tests for factors associated with inflammation in the arteries indicate a higher risk for heart disease, even in people without unhealthy lipids:

C-reactive protein (CRP). CRP is regulated by a very potent immune factor called interleukin-6. Elevated levels have been strongly associated with the inflammatory response and a higher risk for heart attack, even in people with normal cholesterol levels. CRP is also associated with high blood pressure, insulin resistance (the primary problem in type 2 diabetes), and obesity.
A high white blood cell count.
Elevated fibrinogen (a factor responsible for blood clotting).
Lipoprotein-associated phospholipase A2 may prove to be another marker for inflammation and heart disease. Studies suggest that it may play some causal role in coronary artery disease.

A new type of test measures cholesterol levels in the skin. High skin levels may indicate an increased risk for atherosclerosis and serious heart disease.

General Screening Recommendations. Experts groups differ slightly on when screening should start, but the following are generally accepted recommendations:

Periodic cholesterol testing in all adults starting at age 20. Adults with normal cholesterol levels do not need to have the test repeated for 5 years unless changes occur in lifestyle (including weight gain and diet). Adults with risk factors for heart disease or stroke should be rechecked every 2 years.
Selective screening of children who are at risk for high cholesterol and heart disease or familial hypercholesterolemia, which is genetically elevated cholesterol. Risk factors include having parents with total cholesterol levels greater than 240, or having a parent or grandparent who had symptomatic heart disease at age 55 or younger.
Patients already being treated for high cholesterol should be checked every 2 - 6 months.

Lifestyle Changes

Although most studies that prove that lowering cholesterol saves lives are done using drug therapy, the absolute mandate for improving cholesterol levels is to first make changes in lifestyle (both diet and exercise). Even when drugs are used, healthy diet and physical activity are critical companions.

Although there are many major dietary approaches for protecting health, experts generally agree on the following recommendations for heart protection:·

Choose fiber-rich food (whole grains, legumes, nuts) as the main source of carbohydrates, along with a high intake of fresh fruits and vegetables. Walnuts in particular have cholesterol-lowering properties and are a good source of antioxidants and alpha-linolenic acid.
Avoid saturated fats (found mostly in animal products) and trans fatty acids (found in hydrogenated fats and many commercial products and fast foods). Choose unsaturated fats (particularly omega-3 fatty acids found in vegetable and fish oils).
In selecting proteins, choose soy protein, poultry, and fish over meat. A 2006 study found that soy does not help improve cholesterol. However, experts still recommend it as a heart healthy food choice.
Controlling weight, quitting smoking, and exercising are essential companions of any diet program.

After embarking on any heart healthy diet, it generally takes an average of 3 - 6 months before any noticeable reduction in cholesterol occurs. However, some people see improved levels in as few as 4 weeks. An intensive program may be necessary to achieve significant improvements in cholesterol levels and to reduce heart risk factors.

Therapeutic Lifestyle Changes (TLC) from the National Cholesterol Education Program. Guidelines from the National Cholesterol Education Program include these recommendations for preventing and managing high cholesterol levels in adults:

Choose five or more servings of fresh fruits and vegetables and six or more servings of whole grains, legumes. Soluble fiber is preferred (from cereal grains, beans, peas, legumes, and many fruits and vegetables).
Fats can be up to 35% of daily calories, but no more than 7% should be from saturated fat. (People with high triglycerides, low HDL, or both may need a higher fat intake.) Choose fats containing unsaturated fatty acids (from vegetables, fish, legumes, and nuts). Choose margarines containing sterols or stanols (Benecol, Take Control). Avoid trans fatty acids found in commercial baked products.
Protein choices should be fat-free and low-fat milk products, fish, legumes, skinless poultry, and lean meats.
Limit dietary cholesterol intake to less than 200 mg per day.
Maintain healthy body weight and a healthy level of physical fitness.

Mediterranean Diet. The Mediterranean diet is rich in heart-healthy fiber and nutrients, including omega-3 fatty acids and antioxidants. The diet consists of fruits, vegetables, and unsaturated “good” fats, particularly olive oil. Olive oil has been associated with lower blood pressure, a lower risk for heart disease, and possible benefits for people with type 2 diabetes. Olive oil also contains polyphenol, which are phytochemicals that may help boost HDL levels.

A 2006 study that compared several types of Mediterranean diets to a low-fat diet found that Mediterranean diets were better at lowering blood pressure, cholesterol levels, and blood sugar levels after only 3 months. And, in research presented at the 2007 American College of Cardiology annual conference, the Mediterranean diet proved just as good as the American Heart Association low-fat diet for preventing recurrence of heart attack, stroke, or other heart events.

There are several variations to the Mediterranean diet but general recommendations include:

Limit red meats.
Drink one or two glasses of wine each day if alcohol is enjoyable and there are no reasons to restrict its use.
Limit dairy products.
Eat moderate amounts of fish and poultry. Fish is the diet’s main protein source. Some studies suggest that fish is the primary heart-protective ingredient in this diet.
Eat plenty of fresh fruits and vegetables, nuts, legumes, beans, and whole grains.
Season with garlic, onions, and herbs. Unfortunately, garlic does not appear to help lower cholesterol, but it may have other heart benefits. [See Herbs and Supplements in this section.]

Low-Carbohydrate Diets. The Atkins, South Beach, The Zone, and other diet restrict carbohydrate intake include. A 2006 review of low-carbohydrate diets found that they did help weight loss in the short term. However, while these diets appeared to lower triglyceride and raise HDL (“good”) cholesterol levels, they also raised overall and LDL (“bad”) cholesterol levels.

In contrast, a 2007 Journal of the American Medical Association study that compared four different low-carbohydrate and low-fat diet plans (Atkins, Zone, Ornish, and LEARN) found that the Atkins diet was best at raising HDL levels and reducing triglyciderides. In terms of LDL reduction, the low-fat Ornish diet produced the best improvements while the Atkins diet had no effect on LDL. The Atkins diet did result in better moderate weight loss (an average of 10 pounds over the course of a year versus 4 - 6 pounds for the other diet plans), which in itself may have accounted for the improved heart risk factors.

Glycemic Index. Low-carb diets -- such as South Beach, The Zone, and Sugar Busters -- rely on a concept called the "glycemic index," or GI, which ranks foods by how fast and how high they cause blood sugar levels to rise. Foods on the lowest end of the index take longer to digest. Slow digestion wards off hunger pains. It also helps stabilize insulin levels. Foods high on the glycemic index include bread, white potatoes, and pasta while low-glycemic foods include whole grains, fruit, lentils, and soybeans. (These low-glycemic foods are also important components of low-fat diet plans.) A 2006 study indicated that a high-protein, low-glycemic index diet can help produce better reductions in total and LDL cholesterol than a high-protein, high-glycemic index diet. Reducing glycemic load may also help to promote weight loss, especially for women.

Low Fat Diets. Dietary guidelines recommend keeping total fat intake to 20 - 30% of total daily calories, with saturated fat less than 10% of calories. Low-fat diets generally restrict fat intake to 20% or less of total daily calories. The Ornish program, which is recommended for some heart disease patients, limits fats even more drastically. It aims at reducing saturated fats as much as possible, restricting total fat to 10%, and increasing carbohydrates to 75% of calories. In 2006, the largest study to date on low-fat diets found that they did not help prevent heart disease or cancer. Women in the study reduced their fat consumption to 24 - 29% of total daily calories. Some critics say that the study did not do enough to distinguish between good types of fats (monounsaturated omega-3 polyunsaturated) and bad fats (saturated and trans fats).

The DASH Diet. The DASH diet (Dietary Approaches to Stop Hypertension) is proven to help lower blood pressure. Results are sometimes seen within a few weeks. Restricting sodium improves results. The diet appears to have antioxidant effects and may help lower LDL cholesterol levels, although beneficial HDL levels also decline. This diet is not only rich in important nutrients and fiber but also includes foods that contain far more electrolytes, potassium (4,700 mg/day), calcium (1,250 mg/day), and magnesium (500 mg/day) than are found in the average American diet.

A diet that is effective in lowering blood pressure is called Dietary Approaches to Stop Hypertension (DASH).

The DASH diet recommends:

Limit salt intake to no more than 2,300 mg a day (a maximum intake of 1,500 mg a day is an even better goal).
Reduce saturated fat to no more than 6% of daily calories and total fat to 27% of daily calories. (But, include dairy products that are non- or low-fat. Low-fat dairy products appear to be especially beneficial for lowering systolic blood pressure).
When choosing fats, select monounsaturated oils, such as olive or canola oils.
Choose whole grains over white flour or pasta products.
Choose fresh fruits and vegetables every day. Many of these foods are rich in potassium, fiber, or both which may help lower blood pressure.
Include nuts, seeds, or legumes (dried beans or peas) daily.
Choose modest amounts of protein (no more than 18% of total daily calories). Fish, skinless poultry, and soy products are the best protein sources.
Other daily nutrient goals in the DASH diet include limiting carbohydrates to 55% of daily calories and dietary cholesterol to 150 mg. Patients should try to get at least 30 g of daily fiber.

Slight changes to the DASH diet might help lower blood pressure even more, as well as improve cholesterol and lipid levels. Researchers reporting in the Journal of the American Medical Association and at the 2005 American Heart Association meeting said that replacing some carbohydrates in the DASH diet with more protein (from mostly plant sources) or monounsaturated fats may help reduce heart disease risk factors.

Calorie Restriction. Calorie restriction has been the cornerstone of weight-loss programs. Restricting calories in such cases also appears to have beneficial effects on cholesterol levels, including reducing LDL and triglycerides and increasing HDL levels. At this point, reducing calories and increasing exercise is still the best method for maintaining weight loss and preventing serious conditions, notably diabetes. A 2006 study reported that a low-calorie, but nutritionally balanced diet can help prevent an aging-associated change in heart function. Patients in the small study took in 1,400 - 2,000 calories a day for an average of 6 years.

The standard dietary recommendations for losing weight are the following:

As a rough rule of thumb, one pound of fat equals about 3,500 calories, so one could lose a pound a week by reducing daily caloric intake by about 500 calories a day. Naturally, the more severe the daily calorie restriction, the faster the weight loss.
To determine the daily calorie requirements for specific individuals, multiply the number of pounds of ideal weight by 12 - 15 calories. The number of calories per pound depends on gender, age, and activity levels. For instance, a 50-year-old moderately active woman who wants to maintain a weight of 135 pounds might require only 12 calories per pound (1,620 calories a day). A 25-year-old female athlete who wants to maintain the same weight might require 25 calories per pound 2,025 (calories a day).

Fat intake should be no more than 30% of total calories. Most fats should be in the form of monounsaturated fats (such as olive oil). Saturated fats (found in animal products) should be avoided.

Inactivity is one of the four major risk factors for coronary artery disease, on par with smoking, unhealthy cholesterol, and high blood pressure. In fact, studies suggest that people who change their diet in order to control cholesterol only achieve a lower risk for heart disease when they also follow a regular aerobic exercise program.

People who maintain an active lifestyle have a 45% lower risk of developing heart disease than sedentary people. Even moderate exercise reduces the risk of heart attack. One study of women found that just 1 hour of walking a week was associated with a lower risk for heart disease. The effects were similar even in women at high risk for developing heart disease.
Some studies suggest that for the greatest heart protection, it is not the duration of a single exercise session that counts but the total daily amount of energy expended. Therefore, the best way to exercise may be in multiple short bouts of intense exercise.
Burning at least 250 calories a day (the equivalent of about 45 minutes of brisk walking or 25 minutes of jogging) seems to offer the greatest protection against coronary artery disease, most likely because it raises HDL ("good cholesterol") levels. Moderate exercise has little effect on HDL.
Aerobic exercise helps to open up blood vessels and, in combination with a healthy diet, may improve blood-clotting factors.
Resistance (weight) training offers a complementary benefit to aerobics by reducing LDL ("bad cholesterol") levels.
Exercises that train and strengthen the chest muscles may prove to be very important for patients with angina.

Cigarette smoking lowers HDL and is directly responsible for approximately 20% of all deaths from heart disease. The importance of breaking this habit cannot be emphasized enough. Once a person quits smoking, HDL cholesterol levels rise within weeks or months to levels that are equal to their nonsmoking peers. Passive smoking also reduces HDL levels in people exposed to cigarette smoke.

A number of studies have found heart protection from moderate intake of alcohol (one or two glasses a day). Moderate amounts of alcohol help raise HDL levels. Although red wine is most often cited for healthful properties, any type of alcoholic beverage appears to have similar benefit. Pregnant women, anyone who cannot drink moderately, and people with liver disease should not drink at all.

Manufacturers of herbal remedies and dietary supplements do not need FDA approval to sell their products. Just like a drug, herbs and supplements can affect the body's chemistry, and therefore have the potential to produce side effects that may be harmful. There have been a number of reported cases of serious and even lethal side effects from herbal products. Always check with your doctor before using any herbal remedies or dietary supplements.

The following natural remedies are of interest for cholesterol control:

Garlic. Contrary to popular belief, garlic does not significantly reduce cholesterol, according to a 2007 Archives of Internal Medicine study. Researchers tested raw garlic and two types of garlic supplements in 192 patients with moderately high LDL levels. None of the forms of garlic had any effect on LDL levels. However, the researchers note that garlic may still help people with very high LDL levels and it may contain other heart-protective properties.

Policosonol. Policosanol is a nutritional supplement derived from sugar cane that has been promoted as having lipid-lowering benefits. In a randomized, placebo-controlled trial published in 2007 in the Archives of Internal Medicine, policosanol was no better than placebo in reducing LDL levels.

Treatment

In 2004, the National Cholesterol Education Program issued its latest recommendations for cholesterol control and management. These guidelines increase the number of Americans who should be taking LDL-lowering medication.

Starting Medications. Even modest lowering of high cholesterol levels, whether through drug therapy or lifestyle changes, reduces the risk of disability and death from heart disease. Most experts now focus on lowering LDL ("bad") cholesterol. Reducing LDL levels is particularly critical for patients with diabetes.

The doctor will start or consider medication when:

LDL cholesterol is 190 mg/dL or higher.
LDL cholesterol is 160 mg/dL or higher AND patient has one risk factor for heart disease.
LDL cholesterol is 130 mg/dL or higher AND patient has either diabetes or two other risk factors for heart disease.
LDL cholesterol is 100 mg/dL or higher AND patient has heart disease. (If patient has diabetes, even without heart disease, medication may be considered for an LDL cholesterol of 100 mg/dL.)
LDL cholesterol is greater than 70 mg/dL AND patient has had a recent heart attack or has known heart disease along with diabetes, current cigarette smoking, poorly controlled high blood pressure, or the metabolic syndrome (high triglycerides, low HDL, and obesity).

Risk factors for heart disease include:

Having a first-degree female relative diagnosed with heart disease before age 65 or a first-degree male relative diagnosed before age 55
Being male and over age 45 or female and over age 55
Cigarette smoking
Diabetes
High blood pressure
Metabolic syndrome (risk factors associated with obesity such as low HDL levels and high triglycerides)

Recent studies have found that aggressive lipid lowering with high-dose statin therapy is more beneficial than standard statin therapy in patients with existing heart disease. The Pravastatin or Atorvastatin Evaluation and Infection Trial (PROVE-IT) and the Reversal of Atherosclerosis with Aggressive Lipid-Lowering trial (REVERSAL) compared the benefits of standard statin therapy (pravastatin, 40 mg) with intensive statin therapy (atorvastatin, 80 mg) in treating patients with heart disease.

Results from PROVE-IT demonstrated that for high-risk patients, intensive statin therapy is more effective than standard therapy in lowering LDL cholesterol and C-reactive protein (CRP) levels, and that CRP levels predict risk even when LDL cholesterol has been lowered substantially. The REVERSAL data suggest that intensive statin therapy produces greater reductions in LDL and CRP levels, and that the more that statins can lower LDL, the more effective they are in reducing the progression of atherosclerosis.

An important 2006 study found that aggressive treatment with rosuvastatin (Crestor):

Helped lower LDL to below guideline levels
Moderately increased HDL levels
Reduced fatty plaque in the arteries

Experts hoped that these results suggested that statin therapy might have the potential to reverse coronary atherosclerosis. However, a follow-up 2007 study of rosuvastatin indicated that while the drug slowed the rate of atherosclerotic progression, it did not reverse heart disease. Future studies will continue to investigate this issue and to explore whether other statins have a similar positive effect on coronary artery disease. Rosuvastatin lowers LDL more than other statins, but it also carries greater risks for more serious side effects (see Adverse Effects section). Many experts believe that the more that LDL is reduced through statin therapy, the greater the reduction in risk for heart disease, heart attack, and stroke.

It is important to emphasize that cholesterol-lowering medications are used along with healthy lifestyle habits, not in place of them.

Choosing the Correct Lipid-Lowering Medication. Experts now recommend that drug treatments be tailored for raising or lowering specific lipids, depending on the patient's blood lipid picture:

Statins are now the standard drugs for most people who require LDL-lowering therapy. Bile-acid binding resins or niacin may be considered. If LDL goals are not achieved, combinations of a statin with a bile-acid resin or niacin should be considered.
Fibrates or niacin are beneficial for people who need to lower triglycerides and increase HDL.

Considerations for Children and Adolescents. In 2007, the American Heart Association (AHA) issued a scientific statement addressing the use of cholesterol drugs in children and adolescents. The AHA recommends that for children who are overweight or obese, lifestyle modifications (diet, exercise) are preferred over drug therapy and should be the first step in lowering cholesterol.

For children and adolescents who have high-risk cholesterol imbalances -- and have a family history of high cholesterol, heart attack, stroke, and diabetes -- the AHA now recommends statins as the first-line drug therapy.

Considerations for People with Diabetes. At this time, statins are recommended as the best drugs for improving cholesterol and lipid levels in people with diabetes. Studies suggest that they can reduce the risk for adverse heart events in people with diabetes, even if their cholesterol levels are normal or if their diabetes is mild. Furthermore, in one study, a statin was shown to reduce the risk of developing diabetes by 30% in people with high cholesterol. Fibrates may also be useful for people with type 2 diabetes. Niacin (nicotinic acid) has the best effect on the cholesterol profile of people with diabetes but it also increases blood sugar levels. One well-controlled study, however, found that people with diabetes who used niacin had little trouble with glucose control, and some experts believe it now may be used as an alternative to or in combination with statins.


	Effect on High LDL	Effect on Low HDL	Effect on High Triglycerides	Effect on Lp(a)
Statins	Decrease (18 - 55%)	Modest increase (5 - 15%)	Decrease (7 - 30%)	No change
Nicotinic acid (Niacin)	Modest decrease (5 - 25%) In combination with statins, may convert more dangerous LDL type to less dangerous.	Increase (15 - 35%) Drugs of choice for improving HDL levels	Decrease (20 - 50%) Drug of choice for lowering triglycerides	Decrease
Fibrates	Effect varies, but in general has little effect or modest decrease (5 - 20%)	Modest increase (6 - 20%)	Decrease (20 - 50%)	No change
Bile acid-binding resins	Decrease (15 - 30%)	Very modest increase (3 - 5%)	No change	No change

Statins are the most effective drugs for the treatment of high cholesterol, and may even prove important drugs for many people at risk for heart disease who have normal cholesterol levels. Statins inhibit the liver enzyme HMG-CoA reductase, which is used in the manufacturing of cholesterol. These drugs effectively reduce the risk of major coronary events, including first and second heart attacks, in both adult women and men of any age with unhealthy cholesterol levels. Experts estimate a 25 - 30% reduction in mortality rates when patients take statins after a heart attack. (Some believe the decrease may even be greater.) These drugs may also help improve the outcome in patients with heart disease who have had angioplasty.

Important studies have reported lower rates of heart attack, stroke, and mortality rates from all causes in statin users who were at high risk for heart disease, even if they had normal or low cholesterol levels. Benefits were similar in these people regardless of gender, age, or the presence of specific heart risk factors, such as diabetes or peripheral artery disease.

Brands. Statins are currently categorized into four groups:

So-called natural statins, including lovastatin (Mevacor, generics), pravastatin (Pravachol), and simvastatin (Zocor, generics). These are the most studied statins and have proven effectiveness and good safety record.
Synthetic statins include fluvastatin (Lescol) and atorvastatin (Lipitor). Studies using atorvastatin suggest they may reduce LDL more effectively than natural statins. In 2007, Lipitor was approved for additional indications to reduce the risk of heart attacks, strokes, certain types of heart surgery, hospitalization for heart failure, and chest pain in patients with heart disease. Lipitor is also approved for children.
The newer statins include rosuvastatin (Crestor), which was approved in 2003. Trial results have suggested that rosuvastatin is more effective in improving lipid profiles than atorvastatin, simvastatin, or pravastatin. However, like all statin drugs, rosuvastatin can cause serious side effects (see the Adverse Effects section in this report). The risks may be higher for Asian patients; this population should be started on the lowest rosuvastatin dose (5 mg).
Fixed-dose combination statins, which combine two drugs in one pill, first appeared on the market in 2004. Ezetimibe/simvastatin (Vytorin) combines two cholesterol medications that work in different ways. Simvastatin blocks cholesterol production in the liver, while ezetimibe (a non-statin cholesterol medication) blocks cholesterol absorption in the digestive tract. A 2005 study found that Vytorin was more effective than atorvastatin in lowering LDL and increasing HDL levels. Amlodipine/atorvastatin (Caduet) is a dual-therapy medication that combines the antihypertensive calcium channel blocker amlodipine with atorvastatin. It is used to treat simultaneously high blood pressure and high cholesterol.

Statins are generally administered once a day, typically in the evening because most cholesterol synthesis occurs between midnight and 3 a.m. (Atorvastatin and rosuvastatin, however, can be taken in the morning.) Statins are often prescribed along with other cholesterol-lowering drugs such as bile acid-binding resins, nicotinic acid (niacin), and fibrates.

Beneficial Effects on the Heart and Circulation.

Statins are particularly effective for lowering LDL levels. They also reduce triglycerides, apparently in direct proportion to their LDL-lowering effects. Statins also raise HDL levels, but to a lesser extent than other anti-cholesterol drugs. (The newer statins appear to produce more significant increases in HDL.) Evidence now strongly suggests that statins may offer other health benefits beyond lowering cholesterol:

Statins may improve the function of the endothelium (the lining of blood vessels), thereby improving blood flow. (This benefit apparently does not extend to people with diabetes.)
Statins appear to reduce inflammation in the arteries, which is now believed to be a major factor in blood vessel injury.
Some evidence suggests that statins may help prevent blood clotting, a major factor in heart attacks.

Beneficial Effects Outside the Heart. Studies also suggest that the benefits of statins go beyond the heart. At this time, nearly all studies on the following conditions have used natural statins:

Stroke. Statins may reduce the risk for ischemic stroke in high-risk patients with a wide range of cholesterol and lipid levels. (Ischemic strokes occur from blockage in the blood vessels that lead to the brain.) In 2003, statin therapy was shown to reduce both fatal and non-fatal stroke in patients with hypertension and at least three additional cardiovascular risk factors. A 2004 study of stroke patients found that those who were receiving statin therapy at the time of their stroke had more favorable long-term outcomes than patients who were not on statin therapy, suggesting that statin therapy may provide additional benefits to patients who develop stroke.
Diabetes. Statins may have a number of effects that are helpful for patients with diabetes, and may even prevent diabetes in some people with high cholesterol. Statins, however, do not appear to have any effect on blood vessel inflexibility in diabetes, which is an important risk factor for heart disease in these patients. A major 2003 study found that statin therapy helped prevent cardiovascular events including coronary death, heart attack, stroke, and the need for revascularization therapy in patients with diabetes, even in those who did not have high cholesterol levels or established coronary disease.
High Blood Pressure. In an important 2002 study, patients with high blood pressure but normal hMG-CoA reductase or slightly high cholesterol levels had fewer heart attacks and strokes when they took the statin atorvastatin. The study was stopped so all subjects could take statins. An earlier study showed similar benefits with the statin simvastatin.
Alzheimer's Disease. A number of studies have reported a significantly lower risk for Alzheimer's disease in people who take specific statins. Some evidence suggests they may even improve mental function in people without unhealthy cholesterol levels. Statins showing the greatest promise include lovastatin (Mevacor), pravastatin (Pravachol), and atorvastatin (Lipitor.) These statins appear to reduce levels of beta-amyloid. Other statins have not been associated with a lower risk for Alzheimer's. In fact, some researchers are concerned that certain statins that cross the blood-brain barrier may actually worsen Alzheimer's in people who already have it.
Kidney Disease. Statins may prove to protect against heart disease development in patients with mild kidney disorders. According to a 2004 study, statins may also help slow the progression of existing kidney disease.
Eye Disease. Studies are investigating whether statins can help prevent macular degeneration, an age-related eye disease that can lead to blindness. Research is still preliminary, and results have been mixed.

Macular degeneration is a disease of the retina that affects the macula in the back of the eye. The macula is important for clear central vision, allowing an individual to see fine details. There are two types of macular degeneration, dry and wet. Dry macular degeneration is more common and is characterized by the thinning of the retina and drusen, small white deposits that form within the retina. The dry form of macular degeneration is usually mild. Wet macular degeneration can happen more quickly and be more serious. It occurs when vessels under the retinal layer hemorrhage and cause the retinal cells to die, creating blind spots or distorted vision in the central vision. The disease becomes increasingly common among people in each succeeding decade over 50.

Adverse Effects. The statins tend to be better tolerated than other cholesterol-lowering drugs. In many studies the side effects reported were nearly the same as those taking placebo. Side effects may include gastrointestinal discomfort, headaches, skin rashes, muscle aches, sexual dysfunction, drowsiness, dizziness, nausea, constipation, and peripheral neuropathy (numbness or tingling in the hands and feet).

The primary safety concern with statins has involved an uncommon condition called myopathy, which can cause muscle damage and in some cases, muscle and joint pain. A specific myopathy, called rhabdomyolysis, can lead to kidney failure. Reports of rhabdomyolysis prompted the recall of cerivastatin (Baycol) in 2001. The risk for myopathy/rhabdomyolysis is highest at higher doses and in older people (over 65 years), those with hyperthyroidism, and those with renal insufficiency (kidney disease). Both statins and fibrates carry a risk for myopathy. The combination of the two drugs increases this side effect. Some people who use a statin-fibrate combination withdraw from the regimen because of muscle discomfort.

In 2005, the FDA issued a public health advisory for rosuvastatin (Crestor), noting that this drug, like other statins, increased the risk for myopathy and rhabdomyolysis. The risks were greatest at the highest dose level (40 mg). The FDA advises that patients should not start therapy at this dose. In addition, the FDA reported the results of a post-marketing study that found that people of Asian heritage had twice the blood levels of the drug as Caucasians who had taken the same dose. Because of this difference in drug metabolism, the FDA advises that Asian Americans should start treatment at the lowest rosuvastatin dose (5 mg). In general, all statin therapy should start at a lower dose and be raised incrementally until healthy cholesterol levels are maintained. Patients should immediately tell their doctor about any unusual muscle discomfort or weakness, fever, nausea or vomiting, or darkening of urine color.

Statins can also affect the liver, particularly at higher doses, so patients should have periodic liver function tests. Statins should not be taken by anyone with liver problems or by women during pregnancy or breast-feeding. Similarly, high statin doses increase the risk for kidney failure, particularly for patients with other existing risk factors (diabetes, hypertension, atherosclerosis, history of heart failure).

Interactions with Drugs and Food. Statins may have some adverse interactions with other drugs, including other cholesterol-lowering medications. Among the drugs that increase the risk for adverse effects are cyclosporine, macrolide antibiotics, and certain antifungals. Patients should tell their doctors about any other medications they are taking. Grapefruit juice and Seville oranges may increase statin potency.

Brands. Nicotinic acid is the active compound found in niacin, or vitamin B3. It is the first choice for patients with low HDL levels. Brands include Niacor, Nicolar, and Slo-Niacin. An extended-release form (Niaspan), administered at bedtime, may have fewer side effects, including headaches and flushing, than rapidly-acting niacin drugs. Although niacin is available over the counter, the active form used for cholesterol is given in much higher doses and is available only by prescription. It is important to take this medication under a doctor's direction in order to ensure its safety and effectiveness.

Benefits. When used in high doses, it has the following benefits:

Raises HDL levels higher than other anti-cholesterol drugs
Reducing triglyceride levels very effectively
Lowers LDL-cholesterol and lipoprotein(a)
Costs less than other anti-cholesterol drugs

Combinations with other drugs, particularly statins, may add significant benefits.

Side Effects. Many patients do not like the side effects of the rapidly-absorbed form of nicotinic acid. About a quarter of patients who use rapid-acting forms of nicotinic acid stop taking them. The most common side effects are flushing of the face and neck, itching, headache, blurred vision, and dizziness. They usually occur between 5 minutes to hours after taking the drug and can last for minutes to, uncommonly, hours. The body does eventually become tolerant to these effects, and they generally subside.

The following may reduce flushing and itching:

Starting with low doses taken at mealtime and gradually working up to the prescribed dose.
Taking low-dose aspirin about 30 minutes before taking nicotinic acid. This may help prevent flushing.
Avoiding hot drinks.
Choosing an extended release form. (Even with this form, it is wise to gradually increase the bedtime dose over time and take a low-dose aspirin a half-hour beforehand.)

Stomach problems are common. Other side effects include dry skin and mucous membranes and darkening of the skin.

About 30% of patients who take niacin experience elevated levels in blood glucose, which can be a problem for people with diabetes. Niacin's effects on HDL and triglycerides, however, are especially suited for the lipid imbalances that are common in diabetes. And, some studies report that people with diabetes who use niacin have little trouble with blood sugar control.

Potentially Serious Complications. About 3 - 5% of people taking nicotinic acid develop liver problems, which disappear after the medication is discontinued. The extended form (Niaspan) appears to be safe for the liver, but people with chronic liver disease should not use any form of nicotinic acid. People with gout should also avoid nicotinic acid because it elevates uric acid.

Bile-acid binding resins work, as their name suggests, by binding to bile in the digestive tract. This reduces cholesterol in the following way:

Bile is made in the liver and is used as one of the body's primary manufacturing components.

Click the icon to see an image of the gallbladder.

Once the resins bind to bile in the digestive tract, the bile is excreted in feces.
As the resins eliminate bile from the body, the liver takes more cholesterol from the bloodstream in order to produce more bile.
As cholesterol is taken out of the bloodstream, LDL levels drop.

When used in combination with dietary control, LDL levels are reduced by 15 - 20%. Combinations with nicotinic acid are even more effective, with reductions of 40 - 60% observed.

Brands. The bile-acid binding resins and similar drugs include cholestyramine (Questran, Questran Light). They are commonly used in a powder that is dissolved in liquid. Colesevelam (Welchol) is available in tablet form.

Side Effects. None of these drugs poses major risks. Most, however, cause constipation, heartburn, gas, and other gastrointestinal problems, side effects that many people cannot tolerate. One study found that only half the standard dose of colestipol was needed when psyllium, (a soluble fiber supplement found in Metamucil, Fiberall, and Perdiem), was added to the drink. In addition, bloating and constipation were reduced. Colesevelam, a newer resin, appears to have significantly fewer of these side effects.

Bile-acting drugs may contribute to calcium loss and therefore increase the risk for osteoporosis. Over time, deficiencies of vitamins A, D, E, and K may occur, and vitamin supplements may be necessary.

Rarely, toxic effects on the liver have been reported. Patients with liver disorders should be monitored.

Drug Interactions. Bile-acid binding resins may also interfere with other medications, including digoxin (Lanoxin), warfarin, beta-blocker drugs, and a number of medications used to treat low blood sugar. In order to prevent drug interactions, other drugs should be taken 1 hour before or 4 - 6 hours after taking the bile acid-binding resins.

Brands. Fibrates (sometimes called fibric acid derivatives) break down the particles that make triglycerides. Gemfibrozil is the standard fibrate. It is usually taken twice a day, 30 minutes before breakfast and before the evening meal. Newer fibrates, including fenofibrate (Lofibra, Tricor, Triglide), may be more effective in lowering cholesterol than gemfibrozil.

Benefits. Most fibrates have been shown to lower the risk of heart attack. In a 2001 study, men with both low HDL and LDL levels had a slightly lower risk of stroke after taking gemfibrozil. Fibric acid derivatives, or fibrates, have the following effects on cholesterol, lipids, and other factors:

They are good choices for many patients who need to lower triglyceride levels and increase HDL but who cannot take drugs ordinarily used for these purposes, such as nicotinic acid. In one study gemfibrozil, the standard fibrate, reduced the risk for adverse heart events by 22%.
Fibrates can produce modest reductions in LDL levels, although not as effectively as statins or other drugs. LDL may actually increase in patients with very high triglycerides who take these drugs. (The newer fibrates are much more effective in lowering LDL than gemfibrozil.)
A study on bezafibrate suggested it might have anti-inflammatory effects in patients with high triglyceride levels. Inflammation in the blood vessels is now recognized as a major contributor to the process leading to heart disease. However, according to a 2004 study, patients with diabetes or impaired fasting glucose levels were less likely to benefit from bezafibrate.
A study on fenofibrate further suggested that it reduced certain clotting factors (another risk factor for heart disease) and also uric acid (a risk factor for gout). Another study, published in 2004, demonstrated that like bezafibrate, fenofibrate has significant anti-inflammatory properties in patients with high triglyceride levels.

Concerns. Fibrates do not appear to reduce mortality rates. In one study, people who took gemfibrozil had higher rates of death from other causes, including cancer. Some evidence suggests that fibrates may affect receptors involved in cancer development. However, a number of studies have found no higher incidence of cancer.

Side Effects. Side effects may include gastrointestinal discomfort, aching muscles, sensitivity to sunlight, and skin rashes. Fibrates have been known to cause gallstones, so people with gallbladder problems should not use these drugs.

Click the icon to see an image of gallstones in the gallbladder.

The drugs may cause abnormal heart rhythms and can affect the liver and kidney.

Drug Interactions. Fibrates interact with a number of drugs and substances including warfarin, some oral drugs used for diabetes, certain antibiotics, and grapefruit juice.

Ezetimibe (Zetia) blocks absorption of cholesterol that comes from food. Ezetimibe is usually prescribed alone or in combination with a statin. In 2004, the FDA approved Vytorin, which combines ezetimbe and the statin simvastatin into a single pill.

In 2006, the FDA approved the use of ezetimbe in combination with fenofibrate (Tricor) for reduction of total cholesterol and LDL in patients with mixed hyperglycemia (high LDL levels, high triglycerides, low HDL levels) whose cholesterol has not been adequately controlled through diet alone. Fenofibrate is a cholesterol drug that is used along with diet to reduce LDL and triglycerides.

CETP Inhibitors. Cholesteryl ester transfer protein (CETP) inhibitors, such as the experimental drug torcetrapib, are a new drug class that is being investigated for its effect on raising HDL ("good" cholesterol) levels while lowering LDL ("bad") cholesterol levels. Torcetrapib was the most widely studied of these drugs. However, in December 2006, the drug’s manufacturer abruptly stopped late-stage clinical trials after discovering that torcetrapib significantly increased blood pressure and risk of death.

Several studies published in 2007 in the New England Journal of Medicine revealed that while torcetrapib does greatly boost HDL levels (by 61% in one study) and lower LDL, it has no effect on arterial plaque. Scientists are trying to understand why this drug did not work. One theory is that torcetrapib may have increased the quantity of HDL, but not the quality. It is still not clear whether the failure of trocetrapib is specific to this drug or the entire CETP drug class. Given the current findings, it is also unclear whether research will continue on other CETP drugs.

Selective Estrogen-Receptor Modulators(SERMs). Selective estrogen-receptor modulators (SERMs) have been designed to produce the benefits of estrogen without its risks. They are thought to act like estrogen in some tissues but behave like estrogen blockers (antiestrogens) in others. They include tamoxifen (Nolvadex), raloxifene (Evista), and droloxifene. Any beneficial effects of the SERMs on cholesterol and the heart are still unclear. SERMs pose a risk for deep vein blood clots, which may have implications for people with heart problems. Longer studies are needed on possible risks and benefits.

Recombinant ApoA-I Milano. ApoA-I Milano is a type of HDL protein that is found in people with very low levels of HDL. A 2003 study showed that treating patients with a synthetic form of HDL, derived from ApoA-I Milano, caused a significant regression of atherosclerosis. Ongoing trials will evaluate whether this drug can prevent cardiovascular events such as heart attack or death.

Plasmapheresis and Familial Hypercholesterolemia. Plasmapheresis is a blood-filtering procedure that is used to dramatically reduce triglycerides and may also be used to remove LDL. The procedure may be beneficial for patients with severe hereditary forms of high cholesterol who do not respond to other therapies. Studies suggest, for example, that plasmapheresis is particularly useful for patients with familial hypercholesterolemia. The process takes about 3 hours. If not performed regularly, its benefits last only about 2 weeks. People using this procedure are still advised to maintain a healthy diet and continue to take any prescribed medications to control cholesterol.

Resources

www.nhlbi.nih.gov/about/ncep -- National Cholesterol Education Program
www.nhlbi.nih.gov -- National Heart, Lung, and Blood Institute
www.acc.org -- American College of Cardiology
www.americanheart.org -- American Heart Association
www.eatright.org -- American Dietetic Association

References

Berthold HK, Unverdorben S, Degenhardt R, Bulitta M, Gouni-Berthold I. Effect of policosanol on lipid levels among patients with hypercholesterolemiaor combined hyperlipidemia: a randomized controlled trial. JAMA. 2006 May 17;295(19):2262-9.

Covas MI, Nyyssonen K, Poulsen HE, Kaikkonen J, Zunft HJ, Kiesewetter H, et al. The effect of polyphenols in olive oil on heart disease risk factors: a randomized trial. Ann Intern Med. 2006 Sep 5;145(5):333-41.

Crouse JR 3rd, Raichlen JS, Riley WA, Evans GW, Palmer MK, O'Leary DH, et al. Effect of rosuvastatin on progression of carotid intima-media thickness in low-risk individuals with subclinical atherosclerosis: The METEOR Trial. JAMA. 2007 Mar 25; [Epub ahead of print]

Deedwania P, Barter P, Carmena R, Fruchart JC, Grundy SM, Haffner S, et al. Reduction of low-density lipoprotein cholesterol in patients with coronary heart disease and metabolic syndrome: analysis of the Treating to New Targets study. Lancet. 2006 Sep 9;368(9539):919-28.

Estruch R, Martinez-Gonzalez MA, Corella D, Salas-Salvado J, Ruiz-Gutierrez V, Covas MI, et al. Effects of a Mediterranean-style diet on cardiovascular risk factors: a randomized trial. Ann Intern Med. 2006 Jul 4;145(1):1-11.

Gardner CD, Kiazand A, Alhassan S, Kim S, Stafford RS, Balise RR, et al. Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women: the A TO Z Weight Loss Study: a randomized trial. JAMA. 2007 Mar 7;297(9):969-77.

Gardner CD, Lawson LD, Block E, Chatterjee LM, Kiazand A, Balise RR, et al. Effect of raw garlic vs commercial garlic supplements on plasma lipid concentrations in adults with moderate hypercholesterolemia: a randomized clinical trial. Arch Intern Med. 2007 Feb 26;167(4):346-53.

Jolliffe CJ, Janssen I. Distribution of lipoproteins by age and gender in adolescents. Circulation. 2006 Sep 5;114(10):1056-62. Epub 2006 Aug 28.

Kastelein JJ, van Leuven SI, Burgess L, Evans GW, Kuivenhoven JA, Barter PJ, et al. Effect of torcetrapib on carotid atherosclerosis in familial hypercholesterolemia. N Engl J Med. 2007 Mar 26; [Epub ahead of print]

McCrindle BW, Urbina EM, Dennison BA, Jacobson MS, Steinberger J, Rocchini AP, et al. Drug therapy of high-risk lipid abnormalities in children and adolescents. A scientific statement from the American Heart Association Atherosclerosis, Hypertension, and Obesity in Youth Committee, Council of Cardiovascular Disease in the Young, With the Council on Cardiovascular Nursing. Circulation. 2007 Mar 21; [Epub ahead of print]

McMillan-Price J, Petocz P, Atkinson F, O'Neill K, Samman S, Steinbeck K, et al. Comparison of 4 diets of varying glycemic load on weight loss and cardiovascular risk reduction in overweight and obese young adults: a randomized controlled trial. Arch Intern Med. 2006 Jul 24;166(14):1466-75.

Nissen SE, Tardif JC, Nicholls SJ, Revkin JH, Shear CL, Duggan WT, et al. Effect of torcetrapib on the progression of coronary atherosclerosis. N Engl J Med. 2007 Mar 26; [Epub ahead of print]

Review Date:
7/23/2007
Reviewed By:
Alan Greene, MD, FAAP, Chief Medical Officer, A.D.A.M., Inc.; and Harvey Simon, MD, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital.

A.D.A.M. Copyright

adam.com

Exercise

FitSugar — Wed, 08 Oct 2008 17:35:02 -0700

In This Report

Highlights
Introduction
Recommended Exercise Method...
Exercise's Effects on the H...
Exercise's Effects on Diabe...
Exercise's Effects on Bones...
Exercise's Effects on the L...
Exercise's Effects on Weigh...
Exercise's Effects on Other...
Complications
Motivation
Resources
References

HEALTH GUIDE REFERENCE FROM A.D.A.M

Highlights

Chronic Conditions and Exercise:

A new study found that aerobic and resistance training significantly reduced fatigue in men undergoing radiation treatments for prostate cancer. Fatigue is a common side effect of such treatments.
Doctors at the Mayo Clinic found that exercise improves the physical and emotional well-being of patients with Alzheimer's disease. The patients exercised for as little as 60 minutes each week. Doctors noted improvements in areas ranging from depression to wandering.

Exercise and Smoking:

A 2007 review of existing studies found that moderate exercise, for as little as 5 minutes, can help combat the nicotine withdrawal symptoms people experience when they try to stop smoking.

Exercise and Aging:

A 2006 report found that older and elderly adults who exercised twice a week for 4 months significantly increased their body strength, flexibility, balance, and agility. The average age of the study participants was 83.5.

Before and After Exercising:

You should do warm-up exercises for 5 - 10 minutes at the beginning of an exercise session. Low-level aerobic exercise is the best warm-up.
To cool down, you should walk slowly until your heart rate is 10 - 15 beats above your resting heart rate. Stopping too suddenly may sharply reduce blood pressure or cause muscle cramping.
You must be careful when stretching during your warm-up to avoid injuring cold muscles.

Definitions:

Aerobic exercise: Aerobic exercise forces the heart and lungs to work harder for longer periods. It builds endurance, improves blood flow throughout the body, and increases the levels of "good" cholesterol.
Resistance Training: Resistance training works muscles against a force (usually weights). It burns fat and builds muscle.

Introduction

Everyone's goal of living a long and healthy life should include a healthy diet, regular exercise, and maintaining normal weight. The combination of inactivity and eating the wrong foods is the second most common preventable cause of death in the United States (smoking is the first).

Most research on the benefits of exercise focuses on heart protection. Studies clearly show that exercise helps the heart. In addition, new studies are reporting that even people at higher risk for heart disease may lower their risk of dying from it if they exercise.

Evidence suggests that our genes evolved to favor exercise. In other words, during prehistoric times, if a person couldn't move quickly and wasn't strong, he or she died. Those who were fit survived to reproduce and pass on these "fitter" genes. Some researchers believe that with our current inactive lifestyle, these genes produce a number of bad effects, which can lead to many chronic illnesses.

The benefits of exercise include:

Improved oxygen delivery throughout the body
Improved metabolic processes - the way the body breaks down and builds necessary substances
Improved strength and endurance
Decreased body fat
Improved movement of joints and muscles
Improved sense of well-being

In addition, exercise can help change other dangerous lifestyle habits. A 2007 review of existing studies found that moderate exercise, for as little as 5 minutes at a time, can help combat the nicotine withdrawal symptoms people experience when they try to stop smoking.

No one is too young or too old to exercise. The United States Surgeon General recommends at least 30 minutes of moderate exercise, such as brisk walking, nearly every day. However, vigorous exercise carries risks that people should discuss with a doctor. You should always check with your doctor before starting a new exercise program, especially if you have any of the following risk factors:

History of smoking
Obesity
Family history of a long-term disease
A symptom you haven’t told your doctor about
Chest pain
Shortness of breath
Heart palpitations
Blood clots
Infections
Fever
Unexplained weight loss
Foot or ankle sores that won’t heal
Joint swelling
Pain or trouble walking after a fall
Eye injury or eye surgery
Hernia
Hip surgery

Fifty percent of all people who begin a vigorous training program drop out within a year. The key to reaching and maintaining physical fitness is to find activities that are exciting, challenging, and satisfying.

Recommended Exercise Methods

A few simple rules are helpful as you develop your own routine.

Don't eat for 2 hours before vigorous exercise.
Drink plenty of fluids before, during, and after a workout.
Adjust your activity level according to the weather, and reduce it when you are fatigued or ill.
When exercising, listen to the body's warning symptoms, and consult a doctor if exercise causes chest pain, irregular heartbeat, undue fatigue, nausea, unexpected breathlessness, or light-headedness.

Heart rate is the standard guide for determining aerobic exercise intensity. It can be determined by counting one's own pulse or with the use of a heart rate monitor. To feel your own pulse, press the first two fingers of one hand gently down on the inside of the wrist or under the jaw on the right or left side of the front of the neck. You should feel a faint pounding as blood passes through the artery. Each pounding is a beat.

Click the icon to see how to take a radial pulse

Click the icon to see how to take a carotid pulse.

There are different types of heart rates.

Resting heart rate. The average heart rate for a person at rest is 60 - 80 beats per minute. It is usually lower for people who are physically fit, and often rises as you get older. You can determine your resting heart rate by counting how many times your heart beats in one minute. The best time to do this is in the morning after a good night’s sleep before you get out of bed.

Maximum heart rate. To determine your own maximum heart rate per minute subtract your age from 220. For example, if you are 45, you would calculate your maximum heart rate as follows: 220 - 45= 175.

Target heart rate. Your target rate is 50 - 75% of your maximum heart rate. You should measure your pulse off and on while your exercise to make sure you stay within this range. After about 6 months of regular exercise, you may be able to increase your target heart rate to 85% (but only if you can comfortably do so).

Certain heart medications may lower your maximum and target heart rates. Always check with your doctor before starting an exercise program.

Note: Swimmers should use a heart rate target of 75% of the maximum and then subtract 12 beats per minute. The reason for this is that swimming will not raise the heart rate quite as much as other sports because of the so-called "diving reflex," which causes the heart to slow down automatically when the body is immersed in water.


Age	Low	High
	(50% max.)	(75% max.)
20	100	150
30	95	142
40	90	135
50	85	127
60	80	120
Source: American Heart Association

VO2 Max. Serious exercisers may use a VO2 max calculation, which measures the amount of oxygen consumed during intensive, all-out exercise. The most accurate testing method uses computers, but anyone can estimate V02 without instrumentation (with an accuracy of about 95%):

After running at top pace for 15 minutes, round off the distance run to the nearest 25 meters.
Divide that number by 15.
Subtract 133.
Multiply the total by 0.172, then add 33.3.

Olympic and professional athletes train for VO2 max levels above 80. But for the average person interested in fitness, a VO2 max equaling between 50 and 80 is considered an excellent score for overall fitness.

Click the icon to see an image on exercise and heart rate.

Warming up and cooling down are important parts of every exercise routine. They help the body make the transition from rest to activity and back again, and can help prevent soreness or injury, especially in older people.

Warm-up exercises should be practiced for 5 - 10 minutes at the beginning of an exercise session. Older people need a longer period to warm up their muscles. Low-level aerobic exercise such as brisk walking, swinging the arms, or jogging in place, is the best approach.
To cool down, you should walk slowly until the heart rate is 10 - 15 beats above your resting heart rate. Stopping too suddenly can sharply reduce blood pressure, and is dangerous for older people. It may also cause muscle cramping.
Stretching may be appropriate for the cooling down period, but it must be done carefully for warming up because it can injure cold muscles. (There is no clear evidence, however, that stretching reduces muscle injuries.)

Warming up before exercise and cooling down after is just as important as the exercise itself. By properly warming up the muscles and joints with low-level aerobic movement for 5 - 10 minutes, one may avoid injury and build endurance over time. Cooling down after exercise by walking slowly, then stretching muscles, may also prevent strains and blood pressure fluctuation.

For most people, exercise may be divided into three general categories:

Aerobic or endurance
Strength or resistance
Flexibility

A balanced program should include all three. Speed training is also a major category, but generally only competitive athletes practice it.

Benefits of Aerobic Exercise. Regular aerobic exercise provides the following benefits:

Builds endurance
Keeps the heart pumping at a steady and high rate for a long time
Boosts HDL ("good") cholesterol levels
Helps control blood pressure
Strengthens the bones in the spine
Helps maintain normal weight
Improves one's sense of well-being

Types of Aerobic Exercise. Aerobic exercise is usually categorized as high or low impact. Examples of each include the following:

Low- to moderate-impact exercises: Walking, swimming, stair climbing, step classes, rowing, and cross-country skiing. Nearly anyone in reasonable health can engage in some low- to moderate-impact exercise. Brisk walking burns as many calories as jogging for the same distance and poses less risk for injury to muscle and bone.
High-impact exercises: Running, dance exercise, tennis, racquetball, squash. High-impact exercises should be performed no more than every other day, and less often for those who are overweight, elderly, out of condition, or have an injury or other medical problem that would rule out high-impact.

Click the icon to see an image of aerobic exercise.

Aerobic Regimens. As little as one hour a week of aerobic exercises is helpful, but 3 - 4 hours per week are best. Some research indicates that simply walking briskly for 3 or more hours a week reduces the risk for coronary heart disease by 65%. In general, the following guidelines are useful for most individuals:

For most healthy young adults, the best approach is a mix of low- and higher-impact exercise. Two weekly workouts will maintain fitness, but three to five sessions a week are better.
People who are out of shape or elderly should start aerobic training gradually. For example, they may start with 5 - 10 minutes of low-impact aerobic activity every other day and build toward a goal of 30 minutes per day, three to seven times a week. (For heart protection, frequency of exercises may be more important than duration.)
Swimming is an ideal exercise for many elderly and certain people with physical limitations, including pregnant women, individuals with muscle, joint, or bone problems, and those who suffer from exercise-induced asthma.
People who seek to lose weight should aim for six to seven low-impact workouts a week.

One way of gauging the optimal intensity of exercise is to aim for a "talking pace," which is enough to work up a sweat and still be able to converse with a friend without gasping for breath. As fitness increases, the "talking pace" will become faster and faster.

Shoes. All that's really necessary for a workout is a good pair of shoes that are made well and fit well. They should be broken in, but not worn down. They should support the ankle and provide cushioning for impact sports such as running or aerobic dancing. Airing out the shoes and feet after exercising reduces chances for skin conditions such as athlete's foot.

Clothing. Comfort and safety are the key words for workout clothing. For outdoor nighttime exercise, a reflective vest and light-colored clothing must be worn. Bikers, roller bladers, and equestrians should always wear safety devices such as helmets, wrist guards, and knee and elbow pads. Goggles are mandatory for indoor racquet sports. For vigorous athletic activities, such as football, ankle braces may be more effective than tape in preventing ankle injuries.

Aerobic-Exercise Equipment. Home aerobic exercise machines can be adapted to any fitness level and used day or night. Before investing in any exercise machine, however, it is wise to first test it at a gym. In addition, initial supervised training when using these machines can reduce the risk of injury that might occur with self-instruction.

Very inexpensive exercise machines tend to be flimsy and hard to adjust, but many sturdy machines are available at moderate prices. The higher-end models may utilize computers to record calories burned, speed, and mileage. While their readouts may provide motivation and gauge the intensity of a workout, however, they are not always accurate.

The following are a few observations on specific equipment:

A good floor mat is important to provide cushioning for all home exercises.
A simple jump rope improves aerobic endurance for people who are able to perform high-impact exercise. Jumping rope should be done on a floor mat plus a surface that has some give to avoid joint injury.
For burning calories, the treadmill has been ranked best, followed by stair climbers, the rowing machine, cross-country ski machine, and stationary bicycle. (Elliptical trainers, however, may be even better than treadmills for increasing heart rate, calorie expenditure, and oxygen consumption.)
Stationary bikes condition leg muscles and are fairly economical and easy to use safely. The pedals should turn smoothly, the seat height should adjust easily, and the bike's computer should be able to adjust intensity.
Stair machines also condition leg muscles. They offer very intense, low-impact workouts and may be as effective as running with less chance of injury.
Rowing and cross-country ski machines exercise both the upper and lower body.


Aerobic dancing	Sufficient cushioning to absorb shock and pressure that are many times greater than ordinary walking. Arches that maintain side-to-side stability. Thick upper leather support. Toe-box. Orthotics may be required for people with ankles that over-turn inward or outward. Soles should allow for twisting and turning.
Cycling	Rigid support across the arch to prevent collapse during pedaling. Heel lift. Cross-training or combination hiking/cycling shoes may be sufficient for casual bikers. Toe clips or specially designed shoe cleats for serious cyclers. In some cases, orthotics may be needed to control arch and heel and balance forefoot.
Running	Sufficient cushioning to absorb shock and pressure. Fully bendable at the ball of the foot. Sufficient traction on sole to prevent slipping. Consider insoles or orthotics with arch support for problem feet.
Tennis	Allow side-to-side sliding. Low-traction soles. Snug fitting heels with cushioning. Padded toe box with adequate depth. Soft-support arch.
Walking	Lightweight. Breathable upper material (leather or mesh). Wide enough to accommodate ball of the foot. Firm padded heel counter that does not bite into heel or touch ankle bone. Low heel close to ground for stability. Good arch support. Front provides support and flexibility.

Benefits of Strength Exercise. While aerobic exercise increases endurance and helps the heart, it does not build upper body strength or tone muscles. Strength-training exercises provide the following benefits:

Build muscle strength while burning fat
Help maintain bone density
Improve digestion

It is also associated with a lower risk for heart disease, possibly because it lowers LDL (the so-called "bad") cholesterol levels.

Click the icon to see an image of cholesterol.

Strength exercise is beneficial for everyone, even people in their 90s. It is the only form of exercise that can slow and even reverse the decline in muscle mass, bone density, and strength that occurs with aging. Please note: People at risk for cardiovascular disease should not perform strength exercises without checking with a doctor.

Types of Muscle Contractions. There are three types of muscle contractions involved in strength training:

Isometric contractions do not change the length of the muscle. An example is pushing against a wall.
Concentric contractions shorten muscles. An example is the "up" phase of a bicep curl.
Eccentric contractions lengthen muscles. An example is the "down" phase as weights are lowered.

Click the icon to see an image of isometric exercise.

Strength-Training Regimens. Strength training involves intense and short-duration activities. For beginners, adding 10 - 20 minutes of modest strength training two to three times a week may be appropriate. The following are some guidelines for starting a strength regimen:

The sequence of a strength training session should begin with training large muscles and multiple joints at higher intensity and end with small muscle and single joint exercises at lower intensities.
Both shortening and lengthening muscle actions should be performed. Emphasizing the movements that lengthen muscles is of increasing interest. This approach involves slowing and increasing the duration of these "down" movements. It appears to significantly increase blood flow, and some evidence suggests it may achieve stronger muscles more quickly. It may also improve heart function compared to standard movements. Exercises that lengthen muscles may be particularly beneficial for older people and some people with chronic health problems. This type of training increases the risk for muscle soreness and injury, however, and this approach is still controversial.
Strength training involves moving specific muscles in the same pattern against a resisting force (such as a weight) for a preset number of times. This is called a repetition. Students should first choose a weight that is about half of what would require a maximum effort in one repetition. In other words, if it would take maximum effort to do a single repetition with a 10-pound dumbbell, the person would start with a five-pound dumbbell. In the beginning, most people can start with one set of 8 - 15 repetitions per muscle group with low weights. As individuals are able to perform one or two repetitions over their routine, weights can be increased by 2 - 10%.
Breathe slowly and rhythmically. Exhale as the movement begins. Inhale when returning to the starting point.
The first half of each repetition typically lasts 2 - 3 seconds. The return to the original position lasts 4 seconds.
An alternative technique called "super slow" training stretches out one repetition to a 14-second count. This method places far more stress on the muscle group, so fewer repetitions are needed. A full week of recovery is required before repeating this workout. The goal is to initiate changes in the muscles so that the body continues to burn calories after the exercise. Some people report dramatic results from this approach, but scientific proof of these claims is not available. It is a very tedious workout, and people have a hard time sticking with it. People with high blood pressure should not use this approach.
Joints should be moved rhythmically through their full range of motion during a repetition. Do not lock up the joint while exercising it.
For maximum benefit, one should allow 48 hours between workouts for full muscle recovery.

Click the icon to see the proper way to breathe during exercise.

Strength-Training Equipment. Unlike aerobic exercise, strength training almost always requires some equipment. Strength-training equipment does not, however, have to cost anything.

Any heavy object that can be held in the hand, such as a plastic bottle filled with sand or water, can serve as a weight.
Dumbbells (1 - 10 pounds) and resistance bands are inexpensive, portable, and effective.
Wearable weights help strengthen and tone the upper body.
Ankle weights strengthen and tone muscles in the lower body. Wearable ankle weights should not be worn during high-impact aerobics or jumping.
Hand grips strengthen arms and are good for relieving tension.
A pull-up bar can be mounted in a doorway for chin-ups and pull-ups.

More elaborate and expensive home equipment for working body muscles is also available, costing from $100 to over $1,000. No one should purchase or use strength-training equipment without instruction from a professional.

Benefits of Flexibility Training. Flexibility training uses stretching exercises. Many stretching exercises are particularly beneficial for the back. In general, flexibility training provides the following benefits:

Prevents cramps, stiffness, and injuries
Improves joint and muscle movement (improved range of motion)

Certain flexibility practices, such as yoga and tai chi, also involve meditation and breathing techniques that reduce stress. Such practices appear to have many health and mental benefits. They may be very suitable and highly beneficial for older people, and for patients with certain chronic diseases.

Click the icon to see an image of flexibility exercise.

Flexibility Training Regiments. Doctors recommend performing stretching exercises for 10 to 12 minutes at least three times a week. The following are some general guidelines:

When stretching, exhale and extend the muscles to the point of tension, not pain, and hold for 20 - 60 seconds. (Beginners may need to start with a 5- to 10-second stretch.)
Breathe evenly and constantly while holding the stretch.
Inhale when returning to a relaxed position. Holding your breath defeats the purpose; it causes muscle contraction and raises blood pressure.
When doing stretches that involve the back, relax the spine to keep the lower back flush with the mat, and to work only the muscles required for changing position (often these are only the abdominal muscles).

Studies continue to show that it is never too late to start exercising. A report published in the February 2006 Journal of Aging and Health found that elderly adults who exercised twice a week for four months significantly increased their body strength, flexibility, balance, and agility. The exercise program included walking and lifting weights. The average age of the study participants was 83.5. The study adds further evidence that even small improvements in physical fitness and activity can prolong life and independent living.

Still, about half of Americans over 60 describe themselves as sedentary (inactive). According to a 2004 report by the Centers for Disease Control and Prevention, approximately 12% of people aged 65 - 75 years and 10% of people aged 75 years or older meet current recommendations for strength training.

The following tips for exercising may be helpful:

Any older person should have a complete physical and medical examination, as well as professional instruction, before starting an exercise program.
Start low and go slow. For sedentary, older people, one or more of the following programs may be helpful and safe: Low-impact aerobics, gait (step) training, balance exercises, tai chi, self-paced walking, and lower legs resistance training, using elastic tubing or ankle weights. Even in the nursing home, programs aimed at improving strength, balance, gait, and flexibility have significant benefits.
Strength training assumes even more importance as one ages, because after age 30 everyone undergoes a slow process of muscular erosion. The effect can be reduced or even reversed by adding resistance training to an exercise program. As little as one day a week of resistance training improves overall strength and agility. Strength training also improves heart and blood vessel health.
Power training, which aims for the fastest rate at which a muscle or muscle group can perform work, may be particularly helpful for older women in strengthening muscles and preventing falls.
Flexibility exercises promote healthy muscle growth and help reduce the stiffness and loss of balance that accompanies aging.
Chair exercises may be performed by people who are unable to walk.
Older women are at risk for incontinence accidents during exercise. This can be reduced or prevented by performing Kegel exercises, limiting fluids (without risking dehydration), going to the bathroom frequently, and using leakage prevention pads or insertable devices.

Exercise's Effects on the Heart

Inactivity is one of the major risk factors for heart disease. However, exercise helps improve heart health, and can even reverse some heart disease risk factors.

Like all muscles, the heart becomes stronger as a result of exercise, so it can pump more blood through the body with every beat and continue working at maximum level, if need be, with less strain. The resting heart rate of those who exercise is also slower, because less effort is needed to pump blood.

A person who exercises often and vigorously has the lowest risk for heart disease, but any amount of exercise is beneficial. Studies consistently find that light-to-moderate exercise is even beneficial in people with existing heart disease. Note, however, that anyone with heart disease should seek medical advice before beginning a workout program.

The heart is a large muscular organ that pumps blood throughout the body. Valves inside the heart open and close. This controls how much blood enters or leaves the heart.

Exercise has a number of effects that benefit the heart and circulation (blood flow throughout the body). These benefits include improving cholesterol and fat levels, reducing inflammation in the arteries, assisting weight loss programs, and helping to keep blood vessels flexible and open. Studies continue to show that physical activity and avoiding high-fat foods are the two most successful means of reaching and maintaining heart-healthy levels of fitness and weight.

The American Heart Association recommends that individuals perform moderately-intense exercise for at least 30 minutes on most days of the week. This recommendation supports similar exercise guidelines issued by the Centers for Disease Control and Prevention, and the American College of Sports Medicine.

Coronary Artery Disease. People who maintain an active lifestyle have a 45% lower risk of developing heart disease than do sedentary people. Experts have been attempting to define how much exercise is needed to produce heart benefits. In 2002, a well-conducted study on overweight adults confirmed previous research that reported beneficial changes in cholesterol and lipid levels, including lower LDL levels (bad cholesterol), even when people performed low amounts of moderate- or high-intensity exercise such as walking or jogging 12 miles a week. However, more intense exercise is required to significantly change cholesterol levels, notably increasing HDL (good cholesterol). An example of this kind of program would be jogging about 20 miles a week. Such benefits in the study occurred even with very modest weight loss, suggesting that overweight people who have trouble losing pounds can still achieve considerable heart benefits by exercising.

Some studies suggest that for the greatest heart protection, it is not the duration of a single exercise session that counts but the total daily amount of energy expended. Therefore, the best way to exercise may be in multiple short bouts of intense exercise, which can be particularly helpful for older people.

Resistance (weight) training has also been associated with heart protection. It may offer a complementary benefit to aerobics by reducing LDL levels. Exercises that train and strengthen the chest muscles may prove to be very important for patients with angina.

Effects of Exercise on Blood Pressure. Regular exercise helps keep arteries elastic (flexible), even in older people. This, in turn, ensures good blood flow and normal blood pressure. Sedentary people have a 35% greater risk of developing high blood pressure than athletes do.

Click the icon to see the risks associated with untreated hypertension.

It should be noted that high-intensity exercise may not lower blood pressure as effectively as moderate-intensity exercise. In one study, moderate exercise (jogging 2 miles a day) controlled high blood pressure so well that more than half the patients who had been taking drugs for the condition were able to discontinue their medication. However, a small study published in 2005 suggests that moderate exercise does not have a significant impact on systolic blood pressure (the top number) in older adults. While those who exercised did have notable drops in both the top and lower (diastolic) blood pressure levels, the only statistically significant change was the decrease in the lower number.

Experts recommend at least 30 minutes of exercise on most -- if not all -- days. Studies show that yoga and tai chi, an ancient Chinese exercise involving slow, relaxing movements, may lower blood pressure almost as well as moderate-intensity aerobic exercises.

Click the icon to see an image of someone practicing yoga.

Anyone with existing high blood pressure should discuss an exercise program with their doctor. Before starting to exercise, people with moderate-to-severe high blood pressure should lower their pressure, and be able to control it with medications. Everyone, and especially people with high blood pressure, should breathe as normally as possible through each exercise. Holding the breath increases blood pressure.

Effects of Exercise on Heart Failure. Traditionally, heart failure patients have been discouraged from exercising. Now, exercise performed under medical supervision is proving to be helpful for select patients with stable heart failure.

Studies continue to report benefits from exercise training. In one study, heart failure patients as old as 91 years old increased their oxygen use significantly, after 6 months of supervised treadmill and stationary bicycle exercises.
Progressive resistance training may be particularly useful for heart failure patients, since it strengthens muscles, which commonly weaken in this disorder. Even simply performing daily handgrip exercises can improve blood flow through the arteries.

Experts warn, however, that exercise is not appropriate for all heart failure patients.

All stroke survivors should have a pre-exercise evaluation done by their doctor before starting an exercise program.

The effects of exercise on stroke are less established than those on heart disease, but most studies show benefits. The following are some examples:

According to one major analysis, men cut their risk for stroke in half if their exercise program was roughly equivalent to about an hour of brisk daily walking 5 days a week. In the same study, exercise that involved recreation was more protective against stroke than exercise routines consisting simply of walking or climbing.
A 2000 study of women also found substantial protection from stroke in brisk walking or striding (rather than casual walking).

Anyone with heart disease or risk factors for developing heart disease or stroke should seek medical advice before beginning a workout program. Patients with heart disease can nearly always exercise safely as long as they work out under medical supervision. Still, it is often difficult for a doctor to predict health problems that might arise as the result of an exercise program. At-risk individuals should be very aware of any symptoms warning of harmful complications while they exercise.

Some experts believe that anyone over 40 years old, whether or not they are at risk for heart disease, should have a complete physical examination before starting or intensifying an exercise program. Some doctors use a questionnaire for people over 40 to help determine whether they require such an examination. The questions they use are as follows:

Has any doctor previously recommended medically supervised activity because of a heart condition?
Is chest pain brought on by physical activity?
Has chest pain occurred during the previous month?
Does the person faint or fall over from dizziness?
Is bone or joint pain intensified by exercise?
Has medication been prescribed for hypertension (high blood pressure) or heart problems?
Is the person aware of or has a doctor suggested any physical reason for not exercising without medical supervision?

Those who answer "yes" to any of the above questions should have a complete medical examination before developing an exercise program.

Stress Test. A stress test helps determine the risk for a heart problem resulting from exercise. Anyone with a heart condition or history of heart disease should have a stress test before starting an exercise program. Experts currently also recommend this test before a vigorous exercise program for older persons who are sedentary, even in the absence of known or suspected heart disease. The test is expensive, however, and some experts believe that it may not be necessary for many older people with no evident health problems or risk factors.

A small percentage of heart attacks occur after heavy physical work.

High-Risk Individuals. In general, the following people should avoid intense exercise or start it only with careful monitoring:

People who have certain medical conditions: These conditions include uncontrolled diabetes, uncontrolled seizures, uncontrolled high blood pressure, a heart attack within the previous 6 months, heart failure, unstable angina, significant aortic valve disease, or aortic aneurysm.
People with moderate-to-severe hypertension: Experts generally recommend that moderate or severe high blood pressure (systolic blood pressure over 160 mm Hg or diastolic (bottom number) pressure over 100 mm Hg) should be brought to lower levels before a person starts a vigorous exercise program.
Sedentary people should be cautious. One major study found that sedentary people who throw themselves into a grueling workout significantly increase their risk of heart attack.
Episodes of exercise-related sudden death in young people are rare but of great concern. Some are preceded by fainting, which is due to a sudden and severe drop in blood pressure. It should be noted that fainting is relatively common in athletes, and is dangerous only in people with existing heart conditions. Young people with genetic or congenital (present at birth) heart disorders should avoid intensive competitive sports.
Anabolic steroids or products containing ephedra have been associated with cases of stroke, heart attack, and even death.

The risk for heart attack from exercise should be kept in perspective, however. Some form of exercise, carefully personalized, has benefits for most of the individuals mentioned above. In many cases, particularly when the only risk factors are a sedentary lifestyle and older age, exercise can often be increased over time until it is intense.

Hazardous Activities for High-Risk Individuals. The following activities may pose particular dangers for high-risk individuals:

Intense workouts (snow shoveling, slow jogging, speed walking, tennis, heavy lifting, heavy gardening) may be particularly hazardous for people with risk factors for heart disease, especially older people. They tend to stress the heart, raise blood pressure for a brief period, and may cause spasms in the arteries leading to the heart. (See image: Coronary Artery Spasm)
Some studies suggest that competitive sports, which couple intense activity with aggressive emotions, are more likely to trigger a heart attack than other forms of exercise.

Listening for Warning Signs. It should be noted that according to one study, at least 40% of young men who die suddenly during a workout have previously experienced, and ignored, warning signs of heart disease. In addition to avoiding risky activities, the best preventive tactic is simply to listen to the body and seek medical help at the first sign of symptoms during or following exercise. These symptoms include the following:

Irregular heartbeat
Shortness of breath
Chest pain

Click the icon to see an image of a coronary artery spasm.

Click the icon to see an image of stable angina.

Exercise's Effects on Diabetes

Moderate aerobic exercise can lower your risk for type 2 diabetes. An important study found that adults who worked out 2 and 1/2 hours a week cut their risk by 58%.

Exercise has positive benefits for those who have diabetes. It can lower blood sugar, improve insulin sensitivity, and strengthen the heart. Strength training, which increases muscle and reduces fat, may be particularly helpful for people with diabetes, but more evidence is needed to confirm this theory. One study reported that yoga helped patients with type 2 diabetes reduce their need for oral medications.

In 2005, researchers found that people with type 2 diabetes who walked a minimum of 3 miles every day were in better health, and had lower medical expenses, after 2 years of such exercise. Those who remained sedentary for that time period experienced a decline in their overall health and higher health care-related expenses. Study participants who worked out for an average of 38 minutes per day lowered their blood pressure, cholesterol ,and A1C levels (glucose concentration over time). These participants also had lower heart disease risk, even if they didn't lose weight. The increase in the study participants' activity equaled about 2,200 extra steps a day. The findings were reported in the journal Diabetes Care.

An earlier study found that healthy lifestyle changes may work better than the prescription medication metformin (Glucophage), when it comes to preventing metabolic syndrome. Metabolic syndrome is a combination of risk factors including abdominal obesity, insulin resistance, high triglycerides, and hypertension.

The following are precautions for all people with diabetes, whether type 1 or 2:

Because people with diabetes are at higher than average risk for heart disease, they should always check with their doctors before starting a demanding exercise program. For best and fastest results, frequent high-intensity (not high-impact) exercises are best for people who are cleared by their doctor. For people who have been sedentary, or have other medical problems, lower-intensity exercises are recommended, using programs the patients designed with their doctors.
Strenuous strength training or high-impact exercise is not recommended for people with uncontrolled diabetes. Such exercises can strain weakened blood vessels in the eyes of patients with retinopathy (a common diabetic complication). High-impact exercise may also injure blood vessels in the feet.

Patients who are taking medications that lower blood glucose, particularly insulin, should take special precautions before starting a workout program.

Glucose levels swing dramatically during exercise. People with diabetes should monitor their levels carefully before, during, and after workouts.
Patients should probably avoid exercise if glucose levels are above 300 mg/dL or under 100 mg/dL.
To avoid hypoglycemia (low blood sugar), people with diabetes should inject insulin in sites away from the muscles they use the most during exercise.
People with diabetes should drink plenty of fluids. Before exercising, they should avoid alcohol, which increases the risk of hypoglycemia.
Insulin-dependent athletes may need to decrease insulin doses, or take in more carbohydrates, prior to exercise. However, they may need to take an extra dose of insulin after exercise. Stress hormones released during exercise may increase blood glucose level (in people without diabetes, insulin is released to control this increase). People with diabetes must regularly test their blood sugar, and take any medications as instructed by their doctor.

A person with diabetes must regularly check their blood sugar (glucose) level.

Exercise's Effects on Bones and Muscles

Exercise is critical for strong muscles and bones. Muscle strength declines as people age, but studies report that when people exercise they are stronger and leaner than others in their age group.

Exercise helps kids lower their risk of chronic pain in the future. Research has shown that it helps them prevent back and neck pain. The more flexible men are as teenagers, the lower their risk of neck tension in the future, according to a study published in the February 2006 British Journal of Sports Medicine. The same report found that women who had the greatest endurance strength as teenagers had a lower risk of tension neck than those with lower teenager endurance strength. However, men with the greatest endurance strength had higher rates of knee injuries later on.

Joints are complex structures. They are designed to bear weight and move the body. Above the knee is the femur (thigh bone). Below the knee is the tibia (shin bone) and fibula. The kneecap is also called the patella. It rides on top of the lower portion of the femur and the top portion of the tibia. The muscles and ligaments connect these bones and the space between them is cushioned by fluid-filled capsules (synovia) and cartilage. When you exercise, the muscles pull on the bones, strengthening them. The range of motion of a joint represents how far it can be flexed (bent) and extended (stretched).

Joints require motion to stay healthy. Long periods of inactivity cause the arthritic joint to stiffen and the adjoining tissue to weaken. A moderate exercise program that includes low-impact aerobics, power, and strength training has benefits for osteoarthritic patients, even if exercise does not slow down the disease progression. Many patients who start an exercise program report less disability and pain. They are also better able to perform daily chores, and remain independent longer than their inactive peers. Older patients and those with medical problems should always check with their doctor before starting an exercise program.

Click the icon to see an image of osteoporosis.

The following are useful exercises for osteoarthritis patients:

Strengthening exercises builds muscle strength. Some experts encourage patients to emphasize strengthening leg muscles as a first treatment step, even before using pain relievers. They fear that patients who rely on painkilling drugs may overuse knees, which do not have strong enough muscle tissue to protect the joints from further damage. Strengthening the thigh muscles is certainly protective for those who have not developed osteoarthritis.
Range-of-motion exercises increase the amount of movement in a joint and muscle. The best examples are yoga and tai chi, which focus on flexibility, balance, and proper breathing. In one 2001 study, older adults who practiced the gentle movement, breathing, and meditation exercises of tai chi for 10 weeks reported less pain than their peers who did not learn the technique.
Low-impact aerobic workouts help stabilize and support the joints. Cycling and walking are beneficial, and swimming or exercising in water is highly recommended for people with arthritis. Patients with arthritis should avoid high-impact sports, such as jogging, tennis, and racquetball.
Some researchers are now focusing on "power" training, which involves improving the muscle's ability to move more rapidly against resisting forces, such as gravity. For example, such training helps people stand up or climb stairs more quickly. Muscle power declines more rapidly than muscle strength, and may be particularly important in older people.

Exercise is very important for slowing the progression of osteoporosis, and extremely important for reducing the risk of falling, which causes fractures. Falls are one of the leading causes of death in people over the age of 65. Exercise helps build balance and flexibility, which reduces the risk of falling.

Specific exercises may be especially helpful for reducing the risk of fractures:

Weight-bearing exercise is very beneficial for bones in people of all ages, even older people. This approach applies tension to muscle and bone, and the body responds to this stress by increasing bone density, in young adults by as much as 2 - 8% a year. Careful weight training can also be very beneficial for elderly people, particularly women. In addition to improving bone density, weight-bearing exercise reduces the risk of fractures by improving muscle strength and balance, thus helping to prevent falls.
Regular brisk long walks improve bone density and mobility. In one 2002 study, for example, older women reduced their risk of hip fracture by over 40% by working out just four hours a week.
Exercises specifically targeted to strengthen the back can be beneficial in improving posture, and may even reduce kyphosis (hunchback) in people with osteoporosis.
Low-impact exercises, particularly yoga and tai chi, which improve balance and strength, have been found to decrease the risk of falling. In one study, tai chi reduced this risk by almost half.

Click the icon to see an image of the bone-building exercise.

Note on Female Athlete Triad. Some young female athletes who exercise very intensely, and are subject to intense pressure to remain thin, are at risk for the female athlete triad. This syndrome is a combination of three disorders -- an eating disorder, loss of menstrual periods, and osteoporosis.

People who do not exercise regularly face an increased risk for low back pain, especially during times when they suddenly have to perform stressful, unfamiliar activities. These activities may include shoveling, digging, or moving heavy items. Although no definitive studies have been done to prove the relationship between lack of exercise and low back pain, sedentary living is probably a primary nonmedical cause contributing to this condition.

Lack of exercise leads to the following conditions that may threaten the back:

Muscle inflexibility can restrict the back's ability to move, rotate, and bend.
Weak stomach muscles can increase the strain on the back and can cause an abnormal tilt of the pelvis (hip bones).
Weak back muscles may increase the load on the spine and the risk of disk compression.
Obesity puts more weight on the spine and increases pressure on the vertebrae and disks. Studies report only a weak association between obesity and low back pain, however.

Benefits for Chronic Back Pain. People in with sudden and severe back pain should not exercise. Exercise plays a very beneficial role in relieving chronic back pain, however. In one study, patients with back pain lasting for an average of 18 months were assigned eight 1-hour exercise sessions over 4 weeks. They showed greater improvement in nearly every area, including reduced pain, compared to patients who did not exercise.

Exercise should be considered as part of a broader program to return to normal home, work, and social activities. In this way, the positive benefits of exercise not only affect strength and flexibility but they also alter and improve the patients' attitudes toward their disability and pain.

Repetition is the key to increasing flexibility, building endurance, and strengthening the specific muscles needed to support the spine. Some exercise programs used for prevention or treatment of chronic low back pain include the following:

Low-impact Aerobic Exercises: Low-impact aerobic exercises, such as swimming, bicycling, and walking, can strengthen muscles in the abdomen and back without over-straining the back. Programs that use strengthening exercises while swimming may be a particularly beneficial approach for many patients with back pain. In one study, for example, pregnant women who engaged in a water gymnastics program had less back pain, and were able to continue working longer.
Lumbar Extension Strength Training: Exercises called lumbar extension strength training are proving to be effective. Generally, these exercises attempt to strengthen the abdomen, and improve lower back mobility, strength, and endurance. They also enhance flexibility in the hip and hamstring muscles, and in the tendons at the back of the thigh.
Yoga, Tai Chi, and Chi Kung: These exercises combine low-impact physical movements and meditation. They are based on principles of disciplining the mind to achieve a physical and mental balance, and can be very helpful in preventing recurrences of low back pain. In one study of Pilates, an exercise practice that uses yoga principles, the exercises were helpful in a woman with progressive and disabling severe low back pain resulting from early scoliosis. This approach deserves further research.
Flexibility Exercises: Whether flexibility exercises alone offer any significant benefit for chronic back pain is uncertain. One study suggested that any benefits derived from flexibility exercises are lost unless the exercise programs are sustained.
Retraining Deep Muscles: Studies are finding a link between low back pain and poor motor control of deep muscles in the back and trunk. According to these studies, contraction exercises specifically designed to retrain these muscles may be effective for patients with both acute and chronic pain.

It is important for any person who has low back pain to have an exercise program guided by professionals who understand the limitations and special needs of back pain and who can address individual health conditions. One study indicated that patients who planned their own exercise did worse than those in physical therapy or doctor-directed programs.

Hazardous Effects on the Back. Improper or excessive exercise can also cause back pain.

Exercise's Effects on the Lungs

Patients with chronic lung problems have difficulty exercising. Shortness of breath is a major limitation in most patients, but in about a third, muscle fatigue is an even greater problem. Although exercise does not improve lung function, training helps many patients with chronic lung disease by strengthening their limb muscles, thus improving endurance and reducing breathlessness.

In people who already have colds, exercise has no effect on the illness' severity or duration. People should avoid strenuous physical activity when they have fevers, muscle aches, or other symptoms of a widespread viral illnesses.

Long-term exercise may help control asthma and reduce hospitalization. One 2000 study found that aerobic exercise improves breathing capacity and function in patients with mild asthma. People with asthma who enjoy running should probably choose an indoor track, to avoid pollutants. Swimming is particularly excellent for people with asthma. Yoga practice, which uses both stretching, breathing, chest expansion, and meditation techniques may have specific benefits that include stress reduction as well as airway opening. One study reported that two thirds of patients who practiced yoga regularly were able to reduce or eliminate their asthma medications.

Exercise-Induced Asthma. About 40 - 90% of asthma cases are exercise-induced asthma (EIA), in which exercise triggers coughing, wheezing, or shortness of breath. It occurs most often in children and young adults and during intense exercise in cold dry air. EIA is triggered only by exercise. Unlike allergic asthma, there is no long-term increase in airway activity. People who only have EIA do not require long-term maintenance therapy. The warm-up and cool-down periods, which are important for any exercise regimen, may help reduce EIA events. A study of military recruits found that exercise-induced asthma attacks did not hinder their ability to perform or train, suggesting that EIA is not a reason to exclude people from physically demanding occupations.

Exercise-induced asthma is distinct from allergic asthma in that it does not produce long-term increase in airway activity. People who only experience asthma when they exercise may be able to control their symptoms with preventive measures such as warm-up and cool-down exercises.

Walking is the best exercise for people with emphysema. Patients should try to walk three to four times daily for 5 - 15 minutes each time. Devices that assist ventilation may reduce breathlessness that occurs during exercise.

Inspiratory muscle training involves exercises and devices that make inhaling (breathing in) more difficult, in order to strengthen breathing muscles. In a 2001 study, patients who took part in an inspiratory muscle training group improved their breathing, walking capacity, and quality of life. Yoga or martial arts exercises, such as tai chi, which emphasize breathing techniques and balanced movements, may be particularly beneficial for patients with emphysema.

Exercise's Effects on Weight

Exercising helps people reduce their weight, maintain weight loss, and fight obesity. Research has shown that women who regularly exercise but do not change their diet can lose significantly more weight than less active women.

Thirty minutes of moderate-intensity exercise may be adequate to maintain cardiovascular health, but it might not prevent weight gain. Recommendations published in 2003 and 2004 suggest that 45 - 60 minutes of exercise per day is necessary to promote weight loss. Children may need more activity.

Losing significant weight requires both exercise and calorie restriction. In addition, if a person exercises without dieting, any actual weight loss may be minimal because dense and heavier muscle mass replaces fat. Nonetheless, regardless of weight loss, a fit body will look more toned and be healthier.

Exercising without dieting still adds health benefits. One study found that overweight but fit people have half the death rate of overweight, unfit people. Research suggests that people who have trained for a long time develop more efficient mechanisms for burning fat and are able to stay leaner.

Lifting weights builds muscle, which burns calories more efficiently than other body tissues.

The following are some suggestions and observations on exercise and weight loss:

The treadmill burns the most calories of standard aerobic machines. It may be particularly effective when used in short multiple bouts during the day. Exercise sessions as short as 10 minutes, which are done frequently (about four times a day), may be the most successful program for obese people.
The more strenuous the exercise, the longer the body continues to burn calories before returning to its resting level. This state of fast calorie burning can last for as little as a few minutes after light exercise, to as long as several hours after prolonged or heavy exercise.
Resistance (strength) training is excellent for replacing fat with muscles. It should be performed two or three times a week.
Fidgeting may be very helpful in keeping pounds off. Regular exercise is certainly the best course, but for people who must sit for hours at work, frequently shifting positions while sitting may have some benefit.
It is important to realize that as people slim down, they burn fewer calories per mile of walking or jogging. The rate of weight loss slows down, sometimes discouragingly so, after an initial dramatic head start using diet and exercise combinations. People should be aware of this trend and keep adding to their daily exercise routine.
Changes in fat and muscle distribution may differ between men and women as they exercise. Men tend to lose abdominal fat (which lowers their risk for heart disease faster than reducing general body fat). Exercise, however, does not appear to have the same effect on weight distribution in women. A study of women who practiced aerobic and strength training showed the training resulted in fat loss in the women's arms and trunk. However, they did not gain muscle tissue in those areas.

Because obesity is one of the risk factors for heart disease, anyone who is overweight must discuss their exercise program with a physician before starting.

Exercise's Effects on Other Conditions

Physical activity makes you healthier. It lowers your risk for cardiovascular disease and reduces bone loss. Physical activity also helps the body use calories more efficiently, which helps you eliminate body fat and lose weight. It also helps you maintain weight loss by increasing your metabolism and reducing your appetite.

A number of studies have indicated that regular exercise may reduce the risk of breast, colon, and possibly prostate cancers.

Studies confirm that exercise significantly reduces the risk of both colon cancer (by up to 50%) and breast cancer (by up to 30%).

A 2006 study found that, though protection from breast cancer may vary among the types of tumor, exercise offered the most marked protection from the more aggressive tumors. A second study, also done in 2006, supported this finding. Several studies also suggested that more intense exercise is more protective against breast cancer. Exercising consistently throughout life gives the best protection. Exercise not only lowers a woman's chance of getting breast cancer, it can help those who have received chemotherapy for the disease fight off fatigue.

While endurance athletes may suffer from stomach problems, low intensity exercise has a marked protective effect against colon cancer, according to studies, including the Nurses Health Study and the American Cancer Society's Cancer Prevention Study II. Furthermore, a 2006 study found that people with colon cancer who exercise reduce their risk of a recurrence.

Exercise also has a beneficial effect on people receiving treatment for prostate cancer. A new study found that aerobic and resistance training significantly reduced fatigue in men undergoing radiation treatments for prostate cancer. Fatigue is a common side effect of such treatments. In this study, 122 patients received supervised aerobic training, resistance training, or neither. At the end of 24 weeks, participants in both exercise groups noted significant improvement in their fatigue symptoms, compared to the control group. Participants in the resistance training group also lost a significant percentage of their body fat.

Endurance athletes often report stomach problems, such as bloating, diarrhea, and gas, even at rest. Experts suggest that moderate regular exercise might reduce the risk for some intestinal disorders. These disorders include ulcers, irritable bowel syndrome, indigestion, and diverticulosis. Older people who exercise moderately may have a lower risk for severe gastrointestinal bleeding.

Patients with end-stage kidney disease who exercise four to five times per week have better survival rates than those who are less active, according to researchers involved in the Dialysis Morbidity and Mortality Wave 2 study. However, the majority of study participants said that severe physical limitations prevented them from exercising so often.

Studies have shown that regular exercise, particularly walking, helps reduce one's risk for memory loss. A 2005 study found that older men who walked less than a mile daily had a 71% higher risk of dementia than those who walked more than two miles a day. A 2006 study found that people older than 65 who exercise regularly had lower risk of developing dementia, particularly Alzheimer's disease. An earlier study found that walking regularly protects women from mental decline. To date, there are no clear explanations for this apparent benefit. A preliminary study in mice suggests that physical activity changes the way brain-damaging proteins are processed in the brain, thus slowing the development of Alzheimer's disease. Aerobic exercise has been linked with improved reaction time, perception, and math skills in people of all ages.

Doctors found that exercise improves the physical and emotional well-being of patients who already have Alzheimer's disease. The patients exercised moderately for as little as 60 minutes each week. Doctors noted patients who exercised were less depressed, wandered away less, suffered fewer falls, and were placed in nursing homes later, compared to patients who did not exercise.

People with existing neurological diseases, such as multiple sclerosis, Parkinson's disease, and Alzheimer's disease, should be encouraged to exercise. Specialized exercise programs that improve mobility are particularly valuable for patients with Parkinson's disease. Patients with neurological disorders who exercise experience less stiffness, as well as reduction in, and even reversal of, muscle wasting. In addition, the psychological benefits of exercise are extremely important in managing these disorders. Exercise machines, aquatic exercises, and walking are particularly useful.

Some research has suggested that exercise may have antidepressant effects. Although there is little strong evidence that exercise can help manage depression, a number of studies have suggested benefits. Research findings include:

Just 30 minutes of brisk exercise three times a week was as effective as medication in relieving symptoms, and reducing relapse, in many patients with mild-to-moderate depression.
Over half of older women with depression that did not respond to medication improved with 10 weeks of exercise. (About a third of women who did not exercise also improved during that time.)
Studies on elderly, depressed patients report modest benefits from exercise, even in those who do not response to antidepressants. Simply participating in a group activity may help improve mood.
Teenagers who are active in sports have a greater sense of well-being than their sedentary peers. The more vigorously they exercise, the better their emotional health.
Physical inactivity is strongly linked to depression in children 8 - 12 years of age.

Specific exercises may be particularly beneficial:

Aerobics. Either brief periods of intense training or prolonged aerobic workouts can raise levels of certain chemicals in the brain. These chemicals -- which include endorphins, adrenaline, serotonin, and dopamine -- produce the so-called runner's high. Weight loss and increased muscle tone can boost self-esteem.

Yoga. Yoga practice, which involves rhythmic stretching movements and breathing, has been found to positively affect mood. It may have clinical potential as a technique for improving and stabilizing mood. A study comparing yoga to aerobic exercise found that men have significantly lower levels of tension, fatigue, and anger after yoga, compared with levels after swimming. Yoga and swimming tended to produce equal benefits in women.

Click the icon to see an image of the benefits of yoga.

Moderate exercise in healthy pregnant women does not increase the risk for miscarriage, preterm labor, or rupture of the membrane. Not exercising increases the risk for complications, including low-birth weight babies. Exercising increases the fetal heart rate, which in turn protects the baby.

Healthy women with normal pregnancies should exercise at least three times a week, being careful to warm up, cool down, and drink plenty of liquids. Many prenatal calisthenics programs are available.

The following are specific exercises that may benefit the pregnant woman:

Swimming and water aerobics may be the best option for most pregnant women. Swimming has special benefits for those with fluid buildup. Water exercises involve no impact, overheating is unlikely, and swimming face down promotes optimum blood flow to the uterus.
Performing yoga exercises under the guidance of informed instructors can be very helpful.
Walking is also beneficial.

To strengthen pelvic muscles, women should perform Kegel exercises at least six times a day. This involves contracting the muscles around the vagina and urethra for three seconds 12 - 15 times in a row.

Experts generally recommend the following precautions for pregnant women who exercise:

Fit women who have exercised regularly before pregnancy may work out intensely as long as the doctor approves and no discomfort occurs.
As a rule for previously sedentary, low-risk expectant mothers, the pulse rate should not exceed 70 - 75% of the maximum heart rate, or more than 150 beats per minute. Any sedentary expectant mother should check with her doctor before starting an exercise program.
According to one study, vigorous exercise may improve the chances for a timely delivery. All pregnant women, however, should avoid high-impact, jerky, and jarring exercises, such as aerobic dancing, which can weaken the pelvic floor muscles that support the uterus.
During exercise, women should monitor their temperature to avoid overheating, a side effect that can damage the fetus. (Pregnant women should also not use hot tubs or steam baths, which can cause fetal damage and miscarriage.)

Note: Strenuous exercise may affect the flavor of breast milk for a short time afterward. Nursing mothers who engage in such activity might want to wait about an hour after exercising before they feed their infant.

Complications

Exercise may lead to injury if not done properly. Always exercise with care.

Competitive running or high-impact aerobics pose a high risk of a number of injuries to the bones and muscle. The effect of high-impact exercise on the back is not entirely clear. Some research suggests that over time, high-impact exercise may increase the risk for degenerative disk disease. A survey of people who played tennis, however, found no increased risk for low back pain or sciatica.

High-impact exercise can also cause dizziness, ringing in the ear, motion sickness, or loss of high-frequency hearing.

Some research further suggests that in people unused to exercise, intense activity increases production of harmful particles in the body called free radicals. These unstable oxygen particles injure muscle tissue. Muscle pain in this case does not occur until 24 - 48 hours after exercise.

Some people have a higher than average risk for injury:

About half of people at any age who participate in competitive running or high-impact aerobics experience minor injuries at least once a year. Young, intensely competitive athletes may be at risk for permanent injury. Studies are mixed over whether intensive high-impact sports in younger people cause long-term degenerative joint disease.
As the number of older people who start exercising increases, there has also been an increase in injuries for this age group. Between 1990 and 1996, injuries from active sports increased by 54% in people age 65 and older.
Women are far more likely than men to suffer knee injuries.
Urinary incontinence affects many female athletes who engage in high-impact exercise.
Tennis players are at high risk for injuries from repetitive force on the shoulder joint.

Preventing High-Impact Injuries. The following may be helpful for preventing injury:

Wear shock-absorbing footwear with weight-dampening inserts.
Combine weight lifting with jumping exercises. This may prevent injury by strengthening hamstrings and improving coordination.
Vary training and alternate easy and harder workouts.
Be careful to warm up, cool down, and stretch. Flexibility is the key to preventing many muscle strains.
Take days off now and then. The risk of injury increases when athletes train more than five times a week.

Because of the association between high-impact exercises and oxidation, some experts suggest eating foods rich in antioxidants, such as vitamins A, C, and E. Such foods, which may protect against damage from free radicals, include many fresh fruits and vegetables.

Treating Minor Injuries. Most mild or moderate injuries respond well to a simple, four-step treatment: rest, ice, compression, and elevation (RICE). This combination works well for both spot injuries and chronic problems. Ice packs, which reduce inflammation and pain, can help new injuries, and can be useful for the first few hours after a chronically injured area is exercised. How much or how long to compress the injury is unclear.

Evidence suggests that early movement is helpful, although taping or bracing in people with a recurrent ankle sprain is known to be protective. It may not be helpful in those without a previous ankle injury.

Minor injuries like sprains may be treated at home if broken bones are not suspected. The acronym RICE can help you remember how to treat minor injuries: "R" stands for rest, "I" is for ice, "C" is for compression, and "E" is for elevation. Pain and swelling should decrease within 48 hours. Gentle movement may help, but pressure should not be put on a sprained joint until pain is completely gone. This can take up to a few weeks.

Heat, ultrasound, whirlpool, and massage may speed healing if applied a day or two after the initial injury or for warm-up before another workout session.

Some young female athletes who exercise very intensely, and are subject to intense pressure to remain thin, are at risk for a syndrome known as the female athlete triad. This combination of symptoms includes loss of menstruation, eating disorders, and osteoporosis. Eating disorders among young female athletes are estimated at 15 - 62%. Women at higher risk include ballet dancers, gymnasts, and divers. Continued intense exercise causes a stress response in which estrogen (the primary female hormone) is lost. Estrogen loss can lead to infertility and osteoporosis. Iron loss and anemia may also be a problem in women who exercise frequently, even at moderate intensity. A doctor should be consulted for any of these concerns.

Incorrect movements can literally cause mechanical problems in the muscles. These problems are usually the result of improper exercise instruction, and lack of attention. A single jerky golf swing, or the incorrect use of exercise equipment (especially free weights, nautilus, and rowing machines), can cause serious back injuries.

Between 30 - 70% of cyclists experience low back pain. Pain may be improved by adjusting the angle of the bicycle seat.

Everyone should drink lots of fluid during intense exercise. Thirst is often a poor indicator of dehydration in people who exercise, particularly older people. During a tough workout in a hot environment, the body can lose two liters of fluid per hour through sweat.

Anyone who exercises intensely should take the following precautions:

Drink 6 - 8 ounces of fluid about 15 minutes before a workout, and then pause regularly during exercise to drink more.
Water is the best choice for replenishing body fluids. Glucose-sodium-potassium solutions, the so-called "sports drinks," which promise instant energy, appear to be no better than water at improving endurance during prolonged intense running.
Caffeinated beverages like coffee and soft drinks give short bursts of energy, but can actually cause fluid loss. Caffeine before a workout has been shown to temporarily raise blood pressure, and reduces blood flow to inactive limbs.

Contrary to popular belief, drinking fluids will not cause cramps. Drinking enough, in fact, helps prevent the painful involuntary muscle spasms that sometimes occur during exercise.

Overheating, or hyperthermia, can be a problem with hard exercise, or when working out in hot weather. Overheating can cause mild to life-threatening conditions. Heat exhaustion, a moderate form of hyperthermia, is characterized by the following symptoms:

Lightheadedness, nausea, headache, hyperventilation, fatigue, and loss of concentration
A high temperature (above 103° F), possibly accompanied by complaints of chills and clammy skin

Individuals should rest in a cool, dry place, drink plenty of fluids, and bring down their body temperature with ice packs pressed against the skin.

Heatstroke. Heatstroke is the most dangerous complication of hyperthermia. The victim may suddenly stop sweating, after which symptoms such as altered consciousness, seizures, and even coma may quickly follow. Heat stroke is a medical emergency and requires immediate cooling of the victim in an ice-water bath or with ice packs. One study suggests that risk for serious complications from exercising in high temperatures may persist as late as the following day, even if the weather has cooled down.

Click the icon to see an image of the dangers of heatstroke.

Precautions are also necessary in cold weather. When exercising in winter dress in layers, including gloves and socks, which create insulated air pockets that trap heat. In cold weather, wear shoes with less ventilation than those worn in the summer. Fingers, toes, ears, and nose are most susceptible to frostbite. Frostbite progresses from stinging or aching to numbness. Fingers and toes may become white. Soaking the hands and feet in warm water can help, but only once there is no risk of refreezing, since a second bout of frostbite after thawing can quicken tissue damage.

Hypothermia can be life-threatening and can occur even after long exposure to temperatures that are above freezing. The condition is characterized by extreme fatigue, mental confusion, apathy, and a lack of coordination. The victim should be warmed as soon as possible with blankets, body heat, and warm fluids.

Motivation

Motivation, or a lack thereof, is one reason many people stop exercising. Here are some tips for avoiding burnout:

Think of exercise as a menu rather than a diet. Choose a number of different physical activities that are personally enjoyable such as sports, dancing, or biking. Although experts say you should get 30 minutes of aerobic exercises at least five times a week, those times can be divided into shorter periods -- such as 10 minute sessions. In addition, people can achieve health benefits from other exercise programs, including weight training, yoga, or tai chi.
Stick to a prepared schedule and record progress.
Develop an interest or hobby that requires physical activity.
Adopt simple routines such as climbing the stairs instead of taking the elevator, walking instead of driving to the local newsstand, or canoeing instead of zooming along in a powerboat.
Try cross training (regularly switching from one type of exercise to another). Studies suggest it is more beneficial than focusing only on one form of exercise.
Exercise with friends.
Join a gym or take classes. Many affordable programs are available.
For those who can afford them, personal trainers can be very helpful and are available in many gyms and exercise clubs. Personal trainers without any connection to a well-reputed gym or fitness club should be certified by a major fitness organization, such as the Aerobics and Fitness Association of America (AFAA) or the American Council on Exercise.
Exercise videos may also be helpful, but people should be sure they are suited to their individual age and health needs, and bear the seal of the AFAA.
Consider getting a dog. A study in the February 2006 American Journal of Preventive Medicine found that dog owners in Canada walk almost twice as much as those who don’t own a dog. Regular walking is a good way to improve health.

Differences in Motivation Between Men and Women. Motivation factors may differ by gender, and women appear to have a harder time. In one study, weight loss was the greatest motivator to exercise for women, and muscle tone was the primary motivator for men. Unfortunately, effects on appearances may take a long time to show, discouraging people from continuing an exercise program even though their health is improving.

Overweight among children and adolescents has now become an epidemic in the United States. Experts say that children should be vigorously active for at least 20 - 60 minutes 3 - 5 days a week. Parents and schools must be imaginative and rigorous in encouraging children to exercise.

Role of Parents. Parents must make conscious efforts to limit sedentary activities, and to encourage physical ones for their children. This includes monitoring the time children spend on the computer, in front of the TV, or playing video games. Parents should suggest different forms of entertainment. Even children who aren't interested in joining a Little League team may enjoy a round of catch with their parents, walking in the park, or swimming in a local lake.

Role of Schools. Early school physical education programs can make a significant difference and the earlier these routines are learned, the more likely they will be carried forth into a healthy adulthood. Schools should emphasize team cooperation or individual improvement and self-mastery. Studies have shown that people tend to give up more quickly and feel less competent if their perceptions of success are based only on comparison to their peers.

People mature at different rates, and there seems to be a genetic component to coordination, strength, speed, and one's response to resistance exercise. Nonetheless, everyone should strive to be as fit as they possibly can, given their strengths and limitations.

The decision to adopt a healthier behavior -- whether it's more exercise, weight loss, or quitting smoking -- is not as simple as just deciding to do it. Behavior change expert James Prochaska and his colleagues outlined a theory, which has been supported by numerous studies, showing that people cycle through a variety of stages before a new behavior is successfully adopted over the long term. It may help you to understand how this works. As you read the description of each stage -- specifically as it relates to exercise -- you may find yourself nodding and saying to yourself, "Yes, that's me!"

Stage 1: Pre-Contemplation. People at this stage have no plans or desire to exercise. They aren't even considering exercising. They are generally unaware of the specific benefits that exercise can bring -- exercise may seem more like a hassle than something worth doing. Or, they may simply have "failed" in the past and have given up.

There's no point in talking about how to start an exercise program if you are at this stage. Instead, it is important to think about how exercise might be good for you personally -- by helping you to lose weight, feel better, have more confidence, live longer, sleep better, or reduce your stress levels. The benefits must be identified before a person will consider exercise.

If you are at this stage, a good activity is to ask four friends or family members why they exercise. Their answers may show you some real-life benefits, and inspire enough interest to compel you to take the next step.

Stage 2: Contemplation. A person at this stage is thinking, "I think I should probably exercise, but I need help getting started." People at this stage know that exercise is good for them, but it seems like a daunting task or they don't think they can pull it off. Some may have tried and "failed" in the past, but they are still receptive to another go-round.

It's important for people at this stage to consider some of the truths and falsehoods of exercise. For example, it is helpful to know that there are many forms of physical activity to select from, and that you can do your exercising in small chunks. It is not true that exercise has to be painful, or that you either succeed or fail. There is no such thing as "failure" -- people become more or less active at different stages of their lives, and it is never too late to get moving again. And people at this stage should find assurance that an exercise plan can be very simple.

If you are at this stage, a good activity is to write down all the things that you believe make exercise difficult -- and to learn strategies for overcoming or side-stepping those hurdles. People at this stage might benefit from making a pledge, contract, or other commitment that they are going to get more active in the near future. The goal is to get un-stuck by identifying the roadblocks and the ways to overcome these roadblocks. The final goal at this stage is to make a commitment.

Stage 3: Preparation. These folks are primed and motivated. They are ready to give exercise a try. The goal of this stage is to create a specific action plan that takes all factors into account, so that the "launch" is successful. People at this stage need to know how much they should be exercising, their target heart rate, and the types of exercises. They should explore the different kinds of exercises and decide which ones to try.

At this stage, people will evaluate exercise machines and health plans, if that interests them, pick the proper clothing or accessories, and consult a doctor if necessary. They also need to think about how they are going to fit their exercise plans into their daily and weekly schedule.

If you are at this stage, you should also consider some backup plans -- what to do if it rains, or if you don't feel like exercising. That way you are prepared to overcome that hurdle when you encounter it. You should be aware of what to expect realistically at the beginning -- for example, be aware that weight loss takes time, but health benefits begin immediately.

Stage 4: Action! People at this stage have just started exercising. This stage is where the biggest behavior change occurs -- these people have started to exercise but it is not yet a long-term, ingrained habit. This stage requires significant commitment and energy.

If you are at this stage, keep talking to friends and family for inspiration. Review your backup plans. Reward yourself for small achievements. Give yourself notes and reminders to exercise. Having a friend to exercise with can be very helpful as you get through this stage. You want to build and maintain momentum, because exercising gets easier once it is a habit!

Stage 5: Maintenance. The people at this stage have been exercising for at least 6 months. At this point, exercising has started to become a habit. The goal here is to prevent relapse. If you are at this stage, identify ways that you can fine-tune your program. Continue to identify roadblocks and improve your backup plans. Think about what you have found most enjoyable about exercising.

What benefits have you gained? Keep reminding yourself of these perks. If giving yourself a challenge was part of your initial motivation, set new goals and find new challenges. If you risk getting bored with your routine, find ways to vary it. Or maybe you have found a comfortable routine that you enjoy -- if it's working, great! There is no need to change it. You might want to read or learn more about your method of exercising, and develop a deeper level of understanding about it. Soon you'll be a pro!

One point about this theory is that people do not proceed from one stage to another in a simple, step-by-step fashion. They actually cycle or spiral back and forth, so that they may move from stage 1 to 2 to 3, and then back to 2 again. They may stay in maintenance mode for years and then fall back to stage 2. Remember that this is normal -- if you tried exercising in the past and didn't stick with it, don't consider yourself a failure. Just know that it's time to try again!

Resources

http://fitness.gov -- The President's Council on Physical Fitness and Sports
www.ncppa.org --National Coalition for Promoting Physical Activity
www.acefitness.org --American Council on Exercise
www.arthritis.org --The Arthritis Foundation offers tips on exercising with arthritis
www.justmove.org -- Just Move (American Heart Association)

References

Taylor, A.H., Ussher, M., & Faulkner, G. The acute effects of exercise on cigarette cravings, withdrawal symptoms, affect and smoking behaviour: a systematic review. Addiction. 2007;102:534-543.

Kruk J. Lifetime physical activity and the risk of breast cancer: a case-control study. Cancer Detect Prev. 2007;31(1):18- 28.

Tehard B, Friedenreich CM, Oppert JM, et al. Effect of physical activity on women at increased risk of breast cancer: results from the E3N cohort study. Cancer Epidemiol Biomarkers Prev. 2006 Jan;15(1):57-64.

Adams SA, Matthews CE, Hebert JR, et al. Association of physical activity with hormone receptor status: the Shanghai Breast Cancer Study. Cancer Epidemiol Biomarkers Prev. 2006 Jun;15(6):1170-8.

Larson EB, Wang L, Bowen JD et al. Exercise is associated with reduced risk for incident dementia among persons 65 years of age and older. Ann Intern Med. 2006 Jan 17;144(2):73-81.

Meyerhardt JA, Heseltine D, Niedzwiecki D, et al. Impact of physical activity on cancer recurrence and survival in patients with stage III colon cancer: findings from CALGB 89803. J Clin Oncol. 2006 Aug 1;24(22):3535-41.

Slattery ML. Physical activity and colorectal cancer. Sports Med. 2004;34(4):239-52.

Peters HP, De Vries WR, Vanberge-Henegouwen GP et al. Potential benefits and hazards of physical activity and exercise on the gastrointestinal tract. Gut. 2001 Mar;48(3):435-9.

Abbott, RD, White, LR, G. Ross, W, et al. Walking and Dementia in Physically Capable Elderly Men. JAMA. 2004;292:1447-1453

Calton BA, Lacey JV Jr, Schatzkin A, Schairer C, Colbert LH, Albanes D, Leitzmann MF. Physical activity and the risk of colon cancer among women: A prospective cohort study (United States). Int J Cancer. 2006 Feb 17; [Epub ahead of print]

Di Loreto C, Fanelli C, Lucidi P, et al. Make your diabetic patients walk: long-term impact of different amounts of physical activity on type 2 diabetes. Diabetes Care. 2005 Jun;28(6):1295-302.

Mikkelsson LO, Nupponen H, Kaprio J, Kautiainen H, Mikkelsson M, Kujala UM. Adolescent flexibility, endurance strength, and physical activity as predictors of adult tension neck, low back pain, and knee injury: A 25 year follow up study. Br J Sports Med. 2006 Feb;40(2):107-13.

Brown SG, Rhodes RE. Relationships among dog ownership and leisure-time walking in Western Canadian adults. Am J Prev Med. 2006 Feb;30(2):131-6.

Simons R, Andel R. The effects of resistance training and walking on functional fitness in advanced old age. J Aging Health. 2006 Feb;18(1):91-105.

Review Date:
4/30/2007
Reviewed By:
Harvey Simon, MD, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital.

A.D.A.M. Copyright

adam.com

Vitamins

FitSugar — Wed, 08 Oct 2008 17:35:00 -0700

In This Report

Highlights
Introduction
Carotenoids
Phytochemicals
Healthy Foods
Dietary Health Benefits
Resources
References

HEALTH GUIDE REFERENCE FROM A.D.A.M

Highlights

Cancer

Growing evidence suggests that vitamins and micronutrients, especially from foods, may play important roles in the prevention or treatment of certain cancers:

One study found that the risk of prostate cancer risk dropped as consumption of vegetables high in vitamin C, such as broccoli and bell peppers, rose.
A diet high in cruciferous vegetables has been found to reduce the risk of kidney cancer; low consumption of cruciferous vegetables increases the risk.

On the other hand, high amounts of folic acid (a B vitamin) may be associated with colorectal cancer, and beta-carotene supplements are associated with increased lung cancer risk in smokers and people exposed to asbestos.

Macular Degeneration

In 2007, the National Eye Institute recommended that people with intermediate or advanced macular degeneration in one eye take a vitamin formula shown to reduce the risk of macular degeneration in the other eye by 25%. The formula contains vitamin C, vitamin E, beta-carotene, and zinc.

Osteoporosis

Vitamin K is widely used in Japan to treat osteoporosis, and studies suggest it also may be effective in treating rheumatoid arthritis.

Heart Disease

Although people with high levels of homocysteine are prone to developing blood clots in their arteries and veins, a 2007 study found that lowering homocysteine with B vitamins and folic acid does not reduce the incidence of deep vein thrombosis (DVT). A 2007 trial in adults with stable coronary artery disease found that lowering homocysteine levels 33% with folic acid and other B vitamins had no effect on arterial inflammation, meaning that lower levels were unlikely to offer protection against heart attack or stroke.

Introduction

Vitamins do not share a common chemistry, but they do share certain characteristics. They are all organic nutrients that are necessary in small amounts for normal metabolism and good health. Your diet or supplements provide most vitamins. The body can manufacture only three vitamins (D, K, and the B vitamin biotin) from nondietary sources. Unlike carbohydrates, fats, and proteins, vitamins are not sources of energy. Instead, vitamins are chemical partners for the enzymes involved in the body's metabolism, cell production, tissue repair, and other vital processes.

Vitamins are either fat soluble or water soluble. The fat-soluble vitamins, which include A, D, E, and K, are absorbed by the body using processes that closely parallel the absorption of fat. They are stored in the liver and used up by the body very slowly. The water-soluble vitamins include C and the B complex vitamins. The body uses these vitamins very quickly. Excess amounts are eliminated in urine.

The Recommended Daily Allowance (RDA) for vitamins, set by the Food and Nutrition Board of the National Academy of Sciences-National Research Council, has been used for years as a guide for determining the amount of vitamins needed for a healthy diet. The RDA refers to an estimate of the average daily requirement. It is not completely adequate, however, for informing people about the amounts of vitamins they may need.

The RDA is gradually being enhanced using a new standard called the Dietary Reference Intake (DRI). The DRI is based on the following ratings, which will eventually appear on labels:

The recommended daily allowance (RDA). This is the current rating on most vitamins.
The estimated average requirement (EAR). This is the amount adequate for 50% of all people, which will be put on labels when it can be calculated.
Adequate intake (AI). This is an amount that will be used if there is insufficient data to calculate the EAR.
Tolerable upper intake level (UL). This is the maximum dose likely to be safe in nearly all individuals. It will be included on labels if this amount is known.

Food and supplement labels now typically list the Daily Value (DV). This is the percentage of the amount of a nutrient that experts believe a person needs in their daily diet. On food labels it is usually based on one serving size for a person who takes in 2,000 calories a day.

Regulation of dietary supplements by the U.S. Food and Drug Administration (FDA) is a complex issue.

Labels on vitamins and other dietary supplements now include nutrient information and list all ingredients, including identifying parts of plants from which ingredients may be taken. Unlike the labels for drugs, however, labels for vitamins and supplements may not claim to prevent or treat any specific disease. Labels for vitamins and supplements include one of the following:

Health claim -- description of how the substance may reduce the risk of a health-related condition
Nutrient claim -- description of the amount of the nutrient in the product or
Structure or function claim -- description of how the product may affect organs or systems of the body, without claiming to prevent or treat specific disease

The quality of dietary supplements depends on the manufacturer and is not ensured by FDA. The U.S. government does not require that supplements be standardized, meaning that the amounts or quality of nutrients may vary depending on the batch. So, more expensive supplements are not necessarily better than the less expensive ones. Government regulations are in the process of catching up to the boom in the supplement industry. In the meantime, some companies voluntarily adhere to rigorous quality controls, while others do not.

The U.S. Pharmacopeia (USP), an independent organization that sets quality standards for drugs, has also implemented standards for vitamins. Consumers may look for the USP label on products of companies that adhere to these standards. USP verification means the following:

What is in the bottle matches what is listed on the label.
There are no harmful levels of contaminants.
The supplement will be absorbed properly into the body.
It has been produced according to good manufacturing standards.

Before selling any supplement introduced after 1994, manufacturers must submit information as to why the product is considered safe for people. The FDA may refuse to allow it on the market if it finds the evidence insufficient. The FDA does not require manufacturers to provide any scientific evidence that dietary supplements are safe and effective before a product is sold (unlike drugs, which must be proven both safe and effective through clinical trials). If a supplement causes side effects in people once it is for sale, the government may place restrictions on the supplement or withdraw it from the market. The FDA may also withdraw products from the market if their labels are misleading or false.

About 30% of Americans take at least one vitamin or mineral supplement daily. In a large study that examined the death rates of 11,000 people, however, there was no difference in mortality rate between those who took vitamin supplements and those who didn't. Most people who have a healthy diet do not need vitamins, but there are some exceptions.

Pregnant and Breast-Feeding Women. Women who are pregnant or who are breast-feeding generally need additional vitamins. Vitamins B6, B12, and folic acid are particularly important. Women who are vegetarians must be sure to avoid deficiencies, which can harm their offspring. Folic acid reduces the risk for neural tube defects and possibly facial abnormalities, such as cleft palate. Studies also show that low folate levels during pregnancy are associated with low birth weight, a risk factor for the development of cardiovascular disease in adulthood. Multivitamins that contain folic acid also appear to be somewhat protective. A woman's best approach is to take extra folic acid plus multivitamin supplements (which have additional benefits), starting them before becomming pregnant.

The human body stores several years' worth of vitamin B12, so nutritional deficiency of this vitamin is extremely rare. Although, people who follow a strict vegetarian diet and do not consume eggs or dairy products may require vitamin B12 supplements.

Pregnant women with healthy diets may have low folate levels and need to take supplements. Requirements are as follows:

The recommended daily allowance (RDA) for folic acid prior to conception and during pregnancy is 400 mcg.
During breast-feeding 260 - 280 mcg is recommended.

The following vitamins may have some value for pregnant women:

Choline, another vitamin B, is also essential for pregnant (450 mg) and nursing women (550 mg). Choline plays a key role in brain development. Not getting enough during pregnancy can lead to memory and cognitive defects in the baby. Choline supplements can also lessen the cognitive defects of prenatal alcohol exposure.
Vitamin B6 may help improve morning sickness.
Vitamin C may reduce the risk of urinary tract infections during pregnancy.
Vitamin D may help prevent preeclampsia.
One study also suggested that if pregnant women took vitamin K supplements, their infants might not need the required injection of this vitamin after birth, but supplements of vitamin K during pregnancy are not currently recommended.

Some women have low vitamin A reserves in their liver. It is important to note, however, that too much vitamin A significantly increases the risk for birth defects. Daily amounts of 10,000 IU (international units) of vitamin A in supplements and food (an amount not far above the RDA level) can pose a danger. Experts recommend that pregnant women take in no more than 8,000 IU per day and avoid eating liver.

Infants and Children. Infants who are breast-fed by healthy mothers receive enough vitamins except, in some cases, vitamins K and D. Human milk has low levels of K, and the newborn's immature intestinal tract may not produce enough of the baby's own supply. Most babies are given an injection of this vitamin at birth. Infants being breast-fed by malnourished women or those who lack sufficient exposure to sunlight may be deficient in vitamin D. In these cases, supplements of 200 - 300 IU are recommended. Formulas are required to contain sufficient vitamins and minerals. One study suggests that vitamin supplements for infants under 1 year of age may help protect them from developing type 1 diabetes later on. Beyond infancy, most American children receive all the vitamins they need from their diet unless they are living in severely deprived circumstances.

Smokers. Smoking interferes with absorption of several vitamins, importantly vitamins C and D. In one study nearly 25% of female smokers and 31% of male smokers were deficient in vitamin C. Smoking can interfere with the metabolims of vitamin D, resulting in poor muscle function. Taking high doses of antioxidant vitamins, however, may actually be harmful in smokers, especially beta carotene. Instead of taking supplements, most smokers should be sure their diets are rich in fresh fruits and vegetables and whole grains. Of course, smoking cessation is the most important intervention of all.

Click the icon to see an image of sources for vitamin C.

Alcoholics. Alcoholics often suffer from multiple vitamin deficiencies. The most dangerous deficiencies are from vitamins B1 (thiamin), folic acid, B6 (pyridoxine), B2 (riboflavin), and vitamin C. Low levels of B6 are associated with increased risk of colorectal cancer in men who drink large amounts of alcohol.

Overweight Adults. Overweight and obesity causes many problems that often result in metabolic syndrome or type 2 diabetes. Evidence suggests that isoflavones can help regulate cholesterol levels and reduce body weight and fat mass. Because some medications used to control blood sugar levels reduce folic acid and vitamin B12, some people may need vitamin supplements.

People Who Have Had Gastric Bypass Surgery. Vitamin deficiency is a recognized complication of gastric bypass surgery. Women, African-Americans of both sexes, and adults who have had laparoscopic Roux-en-Y bypass surgery are at highest risk. The deficiency is treated with water-soluble vitamin supplements.

Strict Vegetarians. Strict vegetarians need supplements of vitamin B12, unless they get enough of it from fortified cereals and other grain products.

Dieters and Vegetarians. People on weight-reduction diets with less than 1,000 calories a day should probably take a multivitamin and should also check regularly with a physician.

Vegetarians may need riboflavin, vitamin B12, and vitamin D supplements. Vegans, who do not eat dairy or eggs as well as meat, may be at further risk for vitamin A deficiencies if they do not also have plenty of dark colored fruits and vegetables. Those who eat eggs and dairy products need only watch their iron levels.

Deficiencies in vegetarian children may be particularly harmful. (One study, for example, reported that adolescents who had been on macrobiotic diets before age 6 and were deficient in vitamin B12 scored lower on psychological tests.) Pregnant and breast-feeding women who are vegetarians must be sure to have sufficient vitamins. Of special note, maternal deficiencies in vitamin B12 may cause delayed growth and neurologic problems in their newborns.

Click the icon to see an image of sources for vitamin D.

Older Adults. Deficiencies of vitamins and important minerals have been observed in almost a third of elderly people. Often their dietary habits slip and they fail to eat balanced meals regularly. Multiple drug regimens may prevent absorption of some vitamins. Elderly people, particularly if they are not exposed to sunlight, may be deficient in vitamin D. They also may have low levels of important B vitamins. (Older adults showing signs of dementia should be checked for B12 deficiencies as well as other disorders causing mental disturbances.) One study reported that the immune systems of elderly people may benefit from higher levels of vitamin E than the daily recommended dosage. It should be noted, however, that metabolism slows down as a person ages, and in elderly people it takes the liver longer to eliminate drugs and vitamins from the body. The effect of some vitamin supplements, therefore, may be intensified. Dosage levels of vitamin A, for instance, which might be harmless in a younger adult, could be toxic in an elderly patient. Nevertheless, experts are increasingly recommending extra vitamin and mineral supplements for older people.

People Who Need to Avoid Sunlight. People who need to avoid sunlight or are housebound, and whose diet is low in foods that contain vitamin D should take supplements. People with darker skin are at higher risk for deficiencies than those with whiter skin. (Note: vitamin D is toxic in high doses, and no one should exceed the recommended daily intake of vitamin D except under the direction of a physician.)


Benefits	Essential for growth, bone development, night vision, reproduction, and healthy skin.
Recommended daily allowance (RDA) or dietary reference intake (DRI) (mcg = micrograms, mg = milligrams, IU = international units)	Vitamin A RDA and Upper Limit (when toxicity is risk) are the following: For children: 1,000 IU ages one to three (upper limit is 2,000 IU); 1,333 IU ages 4 - 8 (upper limit is 3,000 IU); and 2,000 IU for 9 - 13 (upper limit is 5,665 IU). For nonpregnant women: 2,330 IU ages 14 through adulthood. (Upper limit is 9,335 IU for ages 14 - 18 and 10,000 IU for women over 19.) For pregnant women: 2,500 IU for pregnant women under 18; 2,565 IU for pregnant women over 19. (Upper limit is 9,335 IU for ages 14 - 18 and 10,000 IU for women over 19. It should be noted that some experts recommend 8,000 IU as the upper limit during pregnancy.) Warning: Use of the topical acne medication tretinoin, a vitamin A derivative, during pregnancy can cause birth defects. For nursing women: 4,000 IU for nursing mothers under 18; 4,335 IU for nursing mothers over 19. (Upper limit is 9,335 IU for ages 14 - 18 and 10,000 IU for women over 19.) For men: 3,000 IU ages 14 - 18; 3,000 IU for ages 19 and above. (Upper limit is 10,000 IU.) Note: In determining the daily vitamin A allowance, experts also take note of provitamins, such beta carotene, that convert to vitamin A. Some experts recommend 3 - 6 mg of beta-carotene. Vitamin A is also now being measured with a new unit called the Retinol Activity Equivalent (RAE or RE). One RE is equal to 1 mcg. Retinol is the most active form of vitamin A and it is also converted in the liver from carotenoids. One RE is equal to 12 mcg of beta-carotene or 24 mcg of alpha-carotene or beta-cryptoxanthin).
Foods containing the vitamin	Animal products, such as liver, dairy products, eggs, and fish liver oil. Provitamin A carotenoids are also found in dark red, green, and yellow vegetables and fruits. Requires some dietary fat to be absorbed.
Effects of deficiencies	Skin disorders, severe diarrhea, and eye damage. In less developed countries severe deficiencies cause blindness in 250,000 children each year. Diets low in vitamin A may also increase the risk of developing cancer. Low dietary intake of vitamin A has been associated with impaired lung function in children.
People at risk for deficiencies	Preschool children and any child with inadequate intake of protein, calories, and zinc. Iron deficiency may also impair metabolism of vitamin A. People with asthma. People with serious disorders in the intestine, liver or pancreas, such as cystic fibrosis, steatorrhea, biliary obstruction, inflammatory bowel disease, cirrhosis, and others. People who have undergone Roux-en-Y gastric bypass surgery. Vegans (vegetarians who do not eat eggs and dairy). Such individuals should be sure to have plenty of deep-colored fruits and vegetables. People who abuse alcohol. It should be noted, however, that people with alcoholism may be at risk for vitamin A deficiency, but a combination of high-dose vitamin A and alcohol may cause toxic effects in the liver. Healthy adults usually have a year's store of vitamin A in the liver, so temporary nutritional deficiencies or problems with fat absorption are unlikely to cause serious vitamin A deficiency problems.
Toxicities	Very toxic when taken in high-dose supplements for long periods of time. Symptoms of overdose include dizziness, nausea, vomiting, headache, skin damage, mental disturbances, and, in women, infrequent periods. Can affect almost every part of the body, including eyes, bones, blood, skin, central nervous system, liver, and genital and urinary tracts. Severe toxicity can cause blindness and may even be life threatening. In children, chronic overdose can cause fluid on the brain and as well as adult complications. High consumption of vitamin A may also increase the risk of gastric cancer and the risk of osteoporosis and fractures in both men and women. Pregnant women who take amounts not much higher than RDA levels increase the risk for birth defects in their children. Liver damage can occur in children who take RDA-approved adult levels over prolonged periods of time or in adults who take as little as five times the RDA-approved amount for 7 - 10 years.


	B Vitamins: General Information	Vitamin B1 (thiamin)
Benefits	The B vitamins have a wide and varied range of functions in the human body. Most B vitamins are involved in the process of converting blood sugar into energy.	Essential for converting blood sugar into energy and is involved in metabolic activities in nerves, heart, and muscles and in the production of red blood cells.
Recommended daily allowance (RDA) or dietary reference intake (DRI) (mcg = micrograms, mg = milligrams, IU = international units)		RDA is 1.2 mg per day for men and 1.1 mg for women.
Foods containing the vitamin		Best source is pork and good sources are dried fortified cereals, oatmeal, corn, nuts, cauliflower, and sunflower seeds. Supplements for people with normal diets and health are unnecessary.
Effects of deficiencies	Deficiencies are uncommon in the U.S., but when they occur, they usually involve several B vitamins, since many of them come from the same food groups.	Severe vitamin B1 deficiency is known as beriberi. It can cause visual disturbances, paralysis, staggering, loss of sensation in the legs and feet, psychosis, and congestive heart failure.
People at risk for deficiencies	Alcohol interferes with these vitamins, and some of the physical and mental problems that alcoholics experience may be attributed to a deficiency of B vitamins. Elderly people are also at risk for deficiencies because of inadequate diets and potential interference with B-vitamin absorption by medications. Deficiencies can occur in severely malnourished people or in those receiving long-term dialysis or intravenous feeding. Vegetarians may be at risk.	See general vitamin B description.
Toxicities	Because the B vitamins are water-soluble and eliminated in the urine, toxic reactions from oral administration of most of them are extremely rare. (Exceptions are niacin and B6.) It should be noted that substances known as B15 (pangamic acid) and B17 (laetrile) are neither vitamins nor nutrients; both chemicals are highly dangerous and have no proven nutritional or health value.	No toxic effects have been reported from thiamin.


	Vitamin B2 (riboflavin)	Vitamin B3 (niacin) also known as nicotinic acid	Vitamin B5 (Pantothenic Acid)
Benefits	Important in the production of energy.	Helps break down blood sugar for energy. Acts as a vasodilator, widening blood vessels and increasing blood flow. May be prescribed for improving cholesterol levels.	Important for metabolism of fats, carbohydrates, and proteins, as well as production of steroid hormones and other important chemicals.
Recommended daily allowance (RDA) or dietary reference intake (DRI) (mcg = micrograms, mg = milligrams, IU = international units)	DRI is 1.7 mg.	DRI is 20 mg.	Adequate intake (AI) is 4 - 7 mg.
Foods containing the vitamin	Liver, dried fortified cereals, dairy products, fish. Some dark green vegetables. Supplements for people with normal diets and health are unnecessary.	Mackerel, swordfish, chicken, veal, dried fortified cereals, pork, salmon, and beef liver. Supplements are unnecessary in people with normal health and diets.	Whole grains, beans, milk, eggs, and liver. Supplements are unnecessary in people with normal health and diets.
Effects of deficiencies	Deficiencies affect the skin and mucous membranes and can cause cracks on the lips or corners of the mouth, eczema of the face and genitals, a burning sensation on the tongue, eye irritation. May contribute to anemia when iron levels are low and contribute to elevated levels of homocysteine, a heart risk factor.	Deficiency causes pellagra; symptoms can include eczema, intestinal and stomach distress, depression, headache, thinning of the hair, and excess saliva production.	Deficiency is unlikely except in company with other B vitamin deficiencies. Symptoms include abdominal distress, burning sensation in the heels, and sleep problems.
People at risk for deficiencies	See general vitamin B description.	Alcoholics and any malnourished persons.	Alcoholics and any malnourished persons.
Toxicities	Until recently, no toxic effects had been reported even from large doses of riboflavin. However, one study indicated that high consumption of vitamin B2 might increase the risk of stomach cancer. More research is needed. (In the same study, vitamins B1, B3, and B6 were protective.)	Even mildly high doses of niacin can cause hot flushing of the face and shoulders, headache, itchiness, and stomach problems. Some report heart disturbances and temporarily lowered blood pressure. Large doses may produce ulcers, gout, diabetes, and liver damage, which are usually reversed when high doses are discontinued.	Although no toxicity has been reported in humans, high dosages have caused liver damage in rats.


	Vitamin B6 (pyridoxine)	Vitamin B12 (cobalamin)
Benefits	Has an effect on over 60 proteins in the body, importantly, those that play a role in the nervous system, in red and white blood cell production, and in heart disease.	Essential for the production of blood cells, manufacturing genetic material, and for healthy functioning of the nervous system. New evidence suggests that high levels of B12 may protect against colon and rectal cancer.
Recommended daily allowance (RDA) or dietary reference intake (DRI) (mcg = micrograms, mg = milligrams, IU = international units)	RDA is 1.3 mg in adults under 50 and 1.7 mg for older men and 1.5 for older women. (Some experts recommend 3 to 6 mg for people who need heart protection.) Upper limit is 100 mg for adults.	RDA is 2.4 mcg in men and nonpregnant women, 2.6 mcg in pregnant women, and 2.8 mcg in nursing mothers.
Foods containing the vitamin	Meats, oily fish, poultry, whole grains, dried fortified cereals, soybeans, avocados, baked potatoes with skins, watermelon, plantains, bananas, peanuts, and brewer's yeast.	The only natural dietary sources are animal products, including meats, dairy products, eggs, and fish (clams and oily fish are very high in B12). Like other B vitamins, however, B12 is added to commercial dried cereals.
Effects of deficiencies	Increased levels of homocysteine, associated with heart disease and possibly Alzheimer's disease. Skin problems and nervous system disorders, including impaired memory and concentration. Increased risk for kidney stones. One study found a correlation between vitamin B6 deficiency and inability to conceive or carry a child to term. In unborn children, some evidence shows that lack of vitamin B6, in addition to vitamin B12 and folic acid, may be responsible for defects such as cleft lip and palate and spina bifida. Supplementation with these vitamins is advised during pregnancy. Note: People who have been taking more than 50 mg for some time and stop suddenly are at risk for a so-called rebound deficiency. When people stop, they should taper off slowly.	Deficiencies elevate homocysteine, a possible risk factor for heart disease and Alzheimer's disease. Increased risk of bone fractures. Abnormal gaits in the elderly. May cause severe depression, memory loss, instability, disorientation, and decreased reflexes, and possibly hearing loss. Children who are deficient may experience growth failure. Deficiencies in pregnant and breast-feeding women may cause neurologic harm in their offspring. A genetic defect that causes vitamin B12 deficiencies is responsible for pernicious anemia, a serious disorder that causes rapid heart rate, shortness of breath, dizziness, weakness, and fatigue. It must be treated with injections of vitamin B12 or else neurologic damage may occur.
People at risk for deficiencies	Alcoholics and any malnourished person. In rare cases, infants are born unable to metabolize pyridoxine; in such cases, seizures or convulsions can occur and vitamin B6 must be administered.	Alcoholics and any malnourished persons. Evidence suggests deficiencies may be caused by Helicobacter pylori (H. pylori) bacteria (a cause of ulcers). Nearly 30% of patients with inflammatory bowel disease have vitamin B6 deficiency, as well as low levels of iron and vitamin D. People who take the antibiotic isoniazid, high blood pressure medication hydralazine, and the drug penicillimine are at risk for vitamin B6 deficiency. The elderly and people with Crohn’s disease and those who have undergone ileal and ileocolonic resection may have trouble absorbing natural vitamin B12 and require supplements. Some evidence shows that patients with Parkinson’s disease treated with levodopa plus dopa decarboxylase inhibitor (DDC-i) and catechol-O-methyltransferase inhibitor (COMT-i) have low levels of both vitamin B12 and folate. As a result, they need to take supplements of these vitamins. Other studies have found that patients with diabetes treated with metformin, but not roziglitazone, are at risk for low levels of vitamin B12. Vitamin B12 deficiency is also common in patients with polyneuropathy. In up to one-third of patients, vitamin B12 deficiency is the sole or major contributing cause of their neuropathy. Treatment with vitamin B12 has a high success rate in improving the symptoms. Vegetarians are at higher risk for deficiencies.
Toxicities	Very high doses can cause nerve damage with symptoms of instability and numbness in the feet and hands, which may be permanent in some cases. Of specific concern are possible adverse effects on nerve development in the offspring of pregnant women who take large doses, such as for morning sickness.	There is no evidence of toxicity with this vitamin.


	Biotin (a B vitamin)	Choline (a B vitamin)	Folate, or Folic Acid, its synthetic form (a B vitamin)
Benefits	Involved in the production of amino acid proteins and fatty acids.	Essential for fetal brain development and for learning and memory.	Important for many metabolic processes in the body. It is used in the manufacturing of neurotransmitters (chemical messengers in the brain), in protecting the heart, and for synthesizing genetic materials (DNA) in the cells. It may improve blood flow.
Recommended daily allowance (RDA) or dietary reference intake (DRI) (mcg = micrograms, mg = milligrams, IU = international units)	There is no DRI for biotin; some experts suggest 30-100 mcg.	RDA 425 mg for nonpregnant women, 450 mg for pregnant women, and 550 mg for nursing women.	Supplements may be folate (natural) or folic acid (synthetic). Folic acid is nearly twice as potent as folate. DRI is 400 mcg (.4 mg) of folate for the general population, 600 mcg during pregnancy and 500 mcg while nursing. Women who are planning to be pregnant should certainly take 400 mcg of folic acid before conception, during pregnancy, and while nursing.
Foods containing the vitamin	Dietary sources are eggs, milk, liver, mushrooms, bananas, tomatoes, whole grains, nuts, and brewer's yeast. Also produced by bacteria in the intestines.	Peanuts, eggs, cauliflower, and meats, especially liver.	Avocado, bananas, orange juice, cold cereal, asparagus, green leafy vegetables, dried beans and peas, and yeast. Folic acid supplements are now added to commercial breads and cereals.
Effects of deficiencies	Deficiencies are almost unheard of.	Low levels during pregnancy increase risk of birth defects in newborns.	As with vitamins B6 and B12, deficiencies of folate elevate levels of homocysteine, an amino acid in the body that may increase the risk for heart disease, and possibly Alzheimer's disease. Folic acid supplements lower homocysteine levels, but with little or no impact on risk of atherosclerotic disease in the heart or in the peripheral arteries and veins. This suggests that homocysteine may be a marker of cardiovascular disease, rather than a cause. This being said, one 2007 study found that folic acid supplementation in patients with low folic acids levels substantially reduced the risk of a first stroke. Low levels during pregnancy increase risk of birth defects in newborns, and folic acid supplementation plays a key role in preventing birth defects. Folic acid deficiencies Deficiencies can also cause depression and megaloblastic anemia and impair concentration, memory, and hearing.
People at risk for deficiencies			Alcoholics, malnourished persons, people with conditions that disturb the small intestine, people taking certain drugs, particularly methotrexate. Other risk factors for deficiency: high-dose aspirin, smoking, treatment for seizures, taking oral contraceptives.
Toxicities		Excessive doses can cause intestinal problems, and there is also some concern that high doses can be carcinogenic.	Possible connection between high consumption of folate/folic acid and colorectal cancer now under exploration. Some link between high doses and central nervous system disorders, zinc deficiency, and seizures in epileptics. This risk appears to be low, but results indicate that megadoses should be avoided. High amounts in the elderly may mask symptoms of vitamin B12 deficiencies.


Benefits	Vitamin C is a water-soluble vitamin. Acts as an antioxidant (reduces harm from damaging chemical processes in the body). Essential for the production of collagen, the basic protein in bones, cartilage, tendons, and ligaments. A 2007 study found that vitamin C supplements can help prevent the development of complex regional pain syndrome following wrist fracture. Another study found that prostate cancer risk dropped as consumption of vegetables high in vitamin C, such as broccoli and bell peppers, rose. It may also protect against brochoconstriction during exercise in people with asthma. May help boost the immune system.
Recommended daily allowance (RDA) or dietary reference intake (DRI) (mcg = micrograms, mg = milligrams, IU = international units)	DRI is 75 mg (women) and 90 mg (men). (Smokers need an additional 35 mg.)
Foods containing the vitamin	Citrus fruits and juices, papayas, hot chili peppers, bell peppers, broccoli, potatoes, dark leafy greens, kale, red cabbage, cauliflower, cantaloupe, sweet potatoes, and Brussels sprouts. Orange juice is the most important source of vitamin C in the U.S., with frozen juice being the best source of the vitamin.
Effects of deficiencies	Scurvy is the primary deficiency disease. Affects most body tissues, particularly bones, teeth, and blood vessels. Early symptoms include tiredness, weakness, irritability, weight loss, and vague muscle aches. Later symptoms are bleeding gums, wounds that won't heal, rough skin, and wasting away of the muscles. Deficiencies may contribute to periodontal disease and gallstones. Low dietary intake of vitamin C has been associated with impaired lung function in children. Low intake may also increase lead levels in the blood.
People at risk for deficiencies	Deficiency has been uncommon in the U.S., usually occurring in the elderly, alcoholics, cancer patients, and some people on severely limited diets low in fresh fruits and vegetables. Surprisingly, however, studies now suggest that as many as 16% of middle-aged Americans, with the highest risk in smokers and middle aged men, are deficient in vitamin C. High doses of aspirin taken over a long period of time can interfere with vitamin C.
Toxicities	Tolerable upper limit is 2000 mg/day. High doses may cause headaches and diarrhea. Long-term high doses may increase risk for kidney stones. Ascorbic acid increases iron absorption so people with blood disorders, such as hemochromatosis, thalassemia, or sideroblastic anemia, should avoid high doses. Large doses may also thin blood and interfere with anticoagulant medications, blood tests used in diabetes, and stool tests. Rebound scurvy can occur after abrupt withdrawal from long-term large doses. This may affect infants or pregnant women who withdraw suddenly from high doses.


Benefits	Vitamin D is actually a single term for several hormones that are stored mainly in the liver and also in fat and muscle tissue. It is essential for the absorption of calcium into the bone and for normal bone growth.
Recommended daily allowance (RDA) or dietary reference intake (DRI) (mcg = micrograms, mg = milligrams, IU = international units)	RDA is 200 IU (5 mcg) per day for children and most adults to age 50, 400 IU (10 mcg) for people between ages 50 and 60, and 600 IU over age 70. and 1000 IU (15 mcg) for those over 70. People who are housebound, do not have sufficient exposure to sunlight, or are dark-skinned individuals, as well as breast-fed infants, should take need vitamin D supplements. The maximum tolerated dose after the age of 12 months is 2,000 IU/day
How the body gets the vitamin	There are two forms of vitamin D. Vitamin D3 is made in the body from a chemical reaction to the ultraviolet radiation in sunlight. Vitamin D2 is found in a few food sources, including vitamin D fortified milk, fatty fish, egg yolk, and liver.
Effects of deficiencies	Softening of the bones caused by low levels of calcium and phosphorous (called rickets in children and osteomalacia in adults). Also increases the risk for bone-related knee problems, and hip fractures in postmenopausal women. Associated with a higher risk for prostate cancer and breast cancer risk. Evidence suggests that vitamin D deficiency may be responsible for poor muscle strength after bone fracture. The deficiency is associated with high blood pressure and diabetes, but it is unknown whether supplementation with vitamin D impacts these diseases. Studies now suggest vitamin D plays a role in age-related macular degeneration (AMD), and that drinking milk with added vitamin D can help protect against AMD.
People at risk for deficiencies	Older people, particularly if they live in the North, who are underexposed to sunlight. Obesity may also increase risk. There is some concern, in fact, that vitamin D deficiency may be a growing problem in the US among younger adults as sunscreen use becomes widespread. Individuals at highest risk for vitamin D deficiency are those who assiduously avoid the midday sun, wear protective clothing, regularly use sunscreen, and have dark skin. Exposure to sunlight for about 15 - 20 minutes at mid-morning or mid-afternoon three times a week is recommended for most people who live in temperate climates.
Toxicities	Vitamin D is very toxic in high doses. In infants, daily amounts higher than 1,000 IU can cause mental and growth retardation, kidney failure, and death. In children and adults, daily amounts over 50,000 IU can cause weakness, anorexia, vomiting, diarrhea, and mental changes. Prolonged use of megadoses can cause calcification of soft tissue and life-threatening kidney failure. Low-calcium diets and withdrawal from the vitamin can usually reverse the side effects except for kidney failure.


	Vitamin E (Tocopherol or Tocotrienol)	Vitamin K
Benefits	A fat-soluble antioxidant vitamin that helps prevent cell membrane damage and may inhibit oxidation of LDL cholesterol (a process that increases its harmful effects on arteries). Researchers once thought that vitamin E might protect against cardiovascular disease. This theory has been debunked. However, a 2007 study found that vitamin E supplementation reduced the risk of deep vein thrombosis (DVT) in women at risk for, or with a history of, DVT. Vitamin E supplements have also been shown to produce a statistically significant decrease in menopausal hot flashes. There is also early evidence that vitamin E may protect against ovarian cancer.	The most important function of vitamin K is its role in blood clotting and prevention of bleeding. As a result, the vitamin may be able to help treat hepatoma, leukemia, and hepatocellular carcinoma, a form of liver cancer. The vitamin also contributes to maintaining healthy bones and healing fractures. Vitamin K is widely used in Japan to treat osteoporosis, and studies suggest it may be effective in treating rheumatoid arthritis.
Recommended daily allowance (RDA) or dietary reference intake (DRI) (mcg = micrograms, mg = milligrams, IU = international units)	RDA is 15 mg (22 IU) for all adults, including pregnancy women. Nursing mothers need 19 mg (28 IU). (Supplements should be taken along with some oil or fat to be absorbed.) Vitamin E is composed of 8 compounds (four tocopherols and four tocotrienols). Vitamin E is most often available as supplements of dl alpha tocopherol (a synthetic form). Other vitamin E compounds may prove to be more active than the standard synthetic supplement. They include natural vitamin E, called d-alpha- or RRR-alpha-tocopherol succinate (VES). Other vitamin E compounds of interest are tocotrienol and beta and gamma tocopherol. Supplements that contain a combination of some of these forms may be most beneficial.	RDA is 60 - 65 micrograms (women) and 70 - 80 micrograms (men).
Foods containing the vitamin	Vegetable oils (particularly wheat germ oil), sweet potatoes, turnip greens, mangos, avocados, nuts, sunflower seeds, and soybeans. Tocotrienol (a possibly beneficial form) is found in natural tropical oils. Palm oil sold in the US is refined and does not contain tocotrienol.	Best dietary sources are canola oil, cruciferous vegetables, and soybean oil. Good sources are beef liver, bran, and olive oil. Also produced by bacteria in the intestines.
Effects of deficiencies	Deficiencies have not been established.	Easy bruising, bleeding. May increase the risk of hip fractures in women.
People at risk for deficiencies	Low-birth weight infants. People who eat a low-fat diet. People with medical problems that impair fat absorption, such as Crohn's disease, cystic fibrosis, steatorrhea, liver diseases (such as cirrhosis). People with abetalipoproteinemia, a rare genetic disorder that impairs fat metabolism.	Deficiency may occur in patients who have problems absorbing fats, such as those with cirrhosis, people who are on long-term antibiotic therapy, or who are taking other medications, including cholestyramine, Dilantin, and phenobarbital. Some evidence suggests that more young people may be deficient than previously believed.
Toxicities	Upper level recommended is 1,500 IU of alpha tocopherol. Large doses may cause bleeding problems, particularly in people taking anti-clotting medications. Some research now indicates that vitamin E, like other antioxidants, may have pro-oxidant and damaging effects. Although vitamin E is one of the best studied vitamins, research has yielded conflicting results, and definitive conclusions about the benefits and toxicity of vitamin E have not yet been determined. In a major 2005 study, there was no significant difference in cancer rates between people who took 400 IU of vitamin E daily and those who did not, although those who took the supplement had a higher risk of heart failure. Additional studies also link high levels of vitamin E with a slightly increased risk of heart failure and death. On the other hand, studies show that vitamin E may reduce heart problems in high-risk patients such as certain people with diabetes.	Allergic-type responses, including rash and itching, to high doses have been reported. Those who are taking Coumadin, an anticoagulant, should not take vitamin K without consulting a physician. Vitamin K deficiency can cause anorexia, lethargy, growth retardation, bone loss, soft tissue calcification, and death.

Carotenoids

Carotenoids are a group of more than 700 fat soluble nutrients that produce the colors in foods such as carrots, pumpkins, sweet potatoes, tomatoes, and other deep green, yellow, orange, and red fruits and vegetables. Many are proving to be very important for health. Beta carotene is the most widely studied carotenoid, but others are proving to be of great interest. As with some, but not all, carotenoids, beta carotene is known as a provitamin A because it converts to the vitamin in the body.

They are categorized as either xanthophylls or carotenes according to their chemical composition.

Carotenes are hydrocarbons and most are found in yellow, orange, and red vegetables. They include beta and alpha carotene and lycopene.

Beta Carotene and other Provitamin A Carotenoids. Beta carotene, alpha-carotene, and beta-cryptoxanthin are carotenes that are converted into vitamin A or retinol (the active form of vitamin A) in the body. They are found in many yellow fruits and vegetables. Beta carotene is the most widely studied carotenoid. Evidence now strongly suggests that when taken as a separate supplement it can have harmful effects.
Lycopene. Lycopene is responsible for the red color in fruits and vegetables, including tomatoes, red grapes, watermelon, and pink grapefruit. It is also found in papayas and apricots. It does not convert to vitamin A but may have important cancer fighting properties and other health benefits.
The beneficial actions of most carotenes such as those tomatoes, corn, and carrots, appear to be enhanced by cooking them, especially in oil (preferably olive, canola, or another monounsaturated oil). (Note: Cooking can also destroy certain nutrients, such as vitamin C, in these vegetables.)

Xanthophylls contain oxygen and most are found in green vegetables, such as broccoli, cabbage, and kale. They are also in yellow fruits and vegetables. Xanthophylls include lutein and zeaxanthin, which are both stored in the retina of the eye. Neither converts to vitamin A. Both are powerful antioxidants and may be very important for healthy eyes. Unlike carotenes, cooking may reduce the antioxidant activity of some xanthophylls in foods, although probably not to any significant degree.

Phytochemicals

The word phytochemicals means plant chemicals. Hundreds of phytochemicals are being studied. Many are believed to have a major positive impact on human health. Some contribute to the bright and vivid colors found in fruits and vegetables. The results of studies on specific phytochemicals are not necessarily applicable to the vegetables or fruits that harbor small concentrations of these chemicals.

Nevertheless, it is obvious that vegetables and fruits are healthful, which is probably due to some balance of phytochemicals, carotenoids, vitamins, fibers, and minerals rather than any single substance.

The benefits of individual phytochemical supplements are largely unproven. Furthermore, they are not regulated and high concentrations of some may behave like drugs and can be toxic and possibly even contribute to cancer cell growth.

Polyphenols are important phytochemicals, and flavonoids (or catechins) are members of the polyphenol family that may have significant health benefits. Laboratory studies have shown that specific flavonoids suppress tumor growth, interfere with sexual hormones, prevent blood clots, and have anti-inflammatory properties. In general, flavonoids are found in celery, cranberries, onions, kale, dark chocolate, broccoli, apples, cherries, berries, tea, red wine or purple grape juice, parsley, soybeans, tomatoes, eggplant, and thyme. Most common berries contain flavonoids and are particularly rich in potent antioxidants.

Among the important flavonoids are resveratrol, quercetin, and catechin. Evidence suggests that resveratrol (found in red wine, grapes, olive oil) may be extremely potent. In laboratory studies, it increases cell survival and has been shown to increase the life span of worms and fruit flies. Catechins are the primary flavonoids in tea and may be responsible for its possible beneficial effects. Flavonoids in dark chocolate may also be health protective.

Isoflavones, commonly known as phytoestrogens, have actions that are similar to the female hormone estrogen. A high consumption of soy, which is primarily composed of isoflavones, may reduce symptoms resulting from estrogen depletion during menopause. In a recent study, supplementation with isoflavones decreased hot flashes by 57% and night sweats by 43%, but other research is less favorable.

Lignan is another phytoestrogen and is found in the fiber layers of whole-grains, berries, some seeds, some vegetables, and a few fruits.

Isothiocyanates and related substances, indoles, are also known as mustard oils and are responsible for the sharp taste in cruciferous (also called brassica) vegetables. Such vegetables include broccoli, cabbage, Brussels sprouts, cauliflower, collards, kale, kohlrabi, mustard greens, rutabaga, turnips, and bok choy. Isothiocyanates also stimulate enzymes that convert estrogen to a more benign form and may block steroid hormones that promote breast and prostate cancers. (Cruciferous vegetables are also high in fiber, vitamin C, and selenium.)

Monoterpenes have two important phytochemicals, perillyl alcohol and limonene. They block proteins that stimulate cell growth and reproduction and are being tested for actions against cancer. Limonene is found in the peels of citrus fruits.

Organosulfurs are part of the allium family of phytochemicals. Compounds, such as allicin, may have benefits on the immune system, assist the liver in rendering carcinogens harmless, and reduce production of cholesterol in the liver. These compounds are found in garlic, leeks, onions, chives, scallions, and shallots.

Capsaicin seems to reduce levels of substance P, a compound that contributes to inflammation and the delivery of pain impulses from the central nervous system. Research suggests that it may inhibit cancer-generating substances. It is found in hot red peppers.

Sterols, which include sitosterol, stigmasterol, campesterol, and squalene, are found in vegetable oils. Sitosterol is the most studied and appears to have cholesterol-lowering effects.

Beta-sitosterols may help improve urine flow and urinary symptoms in men with enlarged prostate glands (benign prostatic hyperplasia, or BPH). A recent review study of five randomized trials (519 men) found that urinary flow and other urinary symptoms improved in men who took the herbal remedy from 4 - 26 weeks. The study’s authors cautioned that while beta-sitosterols show effectiveness in the short term, their long-term effectiveness, ability to prevent complications from BPH, and safety are not known. More research is necessary. Beta-sitosterols come from South African star grass, Hypoxis rooperi, or species of Pinus and Picea.

Healthy Foods

Evidence increasingly suggests that a varied diet, not individual food chemicals, is essential for basic health and a longer life. Such diets are rich in fresh fruits and vegetables and whole grains, and low in saturated fats.


Foods	Phytochemicals and Carotenoids	Vitamins and other valuable food components	Benefits
Apples	Flavonoids		May have activity against certain cancers (lung). Also may help maintain healthy cholesterol. May protect against asthma.
Beans	Flavonoids	Folate, iron, potassium, and zinc	Some experts believe beans are the perfect food.
Berries, all kinds of dark colored	Ellegic Acid	Vitamin C, minerals	The anthocyanins in berries such as bilberries, blueberries, cranberries, elderberries, and others, have numerous healthful properties including anti-cancer and antioxidant effects. Bilberry (Vaccinium myrtillis) is widely used to prevent macular degeneration. Blueberries may protect the aging brain. (In one study blueberries were most effective.)
Broccoli (also kale, Brussels sprouts, cauliflower)	Flavonoids, isothiocyanates, lutein, beta and alpha carotene. Note: Young sprouts of broccoli and cauliflower contain much higher levels of isothiocyanates than their mature forms.	Vitamin C, folate, fiber, and selenium	Anticancer properties. Protective against heart disease and stroke.
Carrots and other bright yellow vegetables	Lutein, beta carotene and other provitamin A carotenoids	Vitamin A (converted from carotenoids), vitamin C	Protects eyes, lungs. (Cooking carrots may increase the potency of food nutrients.)
Chocolate, dark. Note: Milk chocolate does not have benefits.	Flavonoids		Heart protective (may improve lipids and help prevent blood clotting. May have protective properties against lung cancer (not other cancers).
Eggs	Lutein	Many B vitamins, vitamin A, vitamin D	Although egg yolks are high in cholesterol, very little of it has a negative effect on people with normal levels. And the health benefits of eggs are now known to be very high. (People with diabetes or those with high cholesterol should restrict eggs, however.)
Fish, oily (mackerel, salmon, sardines)		Vitamin B3, B12. Essential fatty acids, selenium	Heart and brain protective.
Garlic	Allium (organosulfurs)		Possibly protective against certain cancers, heart diseases, and infection. Heating garlic can reduce benefits. Allowing crushed fresh garlic to stand 10 minutes before heating, however, may preserve beneficial chemicals while cooking.
Ginger	Zingiberaceae		Cancer fighting properties.
Grains (whole)	Lignans (phytoestrogens)	Vitamin B, Selenium (important antioxidant mineral), fiber, folate	May help reduce the ability of cancer cells to invade health tissue.
Grapes, including purple grape juice, and red wine	Flavonoids, (resveratrol, quercetin and catechin)		Fight heart disease and cancer. May help lower the risk for asthma.
Nuts		Vitamin E, vitamin B1, essential fatty acids, folate	Protects the heart and may help prevent stroke.
Onions	Flavonoids, allium (organosulfurs)		May have activity against certain cancers (lung).
Oranges	Monoterpenes	Vitamin C, folate, potassium.	Many health benefits. Increases HDL levels.
Potatoes (Sweet)		Vitamin C, vitamin E, vitamin A	Many health benefits.
Soy. The best products are tofu, soy milk, or whole soy protein.	Isoflavones (phytoestrogens), flavonoids, phytosterol, phytate, saponins.		May have effects similar to estrogen, including maintaining bone and benefiting the heart in women. May also be protective against prostate cancer and possibly other cancers. More studies are needed. Effects on breast cancer are uncertain. (Note: Soy may have different effects in men than in women. Of some concern is one study reporting more mental decline in men who consume greater amounts of tofu.)
Spinach and other dark green leafy vegetables	Zeaxanthin, Beta carotene	Vitamin C, folate, vitamin A (converted from carotenoids)	Protects lungs and brain.
Tea (Both black and green tea are beneficial. Best results associated with green tea.)	Flavonoids (primarily catechins)		Cancer fighting properties, particularly in green tea, which may be especially beneficial for smokers. Both black and green tea may protect against heart disease and stroke, although studies are mixed. Tea drinking also may help with weight control and help prevent osteoporosis.
Tomatoes	Lycopene, Flavonoids	Vitamin C, biotin, minerals	Studies link to reductions in prostate and other cancers. Infection fighters.
Note on Organic versus Inorganic Products. There is some evidence that organic produce has higher levels of antioxidants and that some agricultural chemicals may destroy flavonoids. Nevertheless, organic produce is expensive, and fruits and vegetables, no matter how they are grown, are still filled with healthful nutrients.

Dietary Health Benefits

The benefits of any dietary factors are very difficult to prove, and, to date, there is little evidence that most dietary supplements protect against major diseases in otherwise healthy people with normal eating habits. An exception is lutein, which is known to reduce the risk of macular degeneration. However, a diet naturally high in vitamins and minerals can be the best defense against many diseases. Fresh fruits and vegetables and whole grains are the primary sources of vitamins, carotenoids, and vitamins, as well as of fiber and important minerals.

Description of Oxygen-Free Radicals (Oxidants). Currently, the most important benefit claimed for vitamins A, C, E, and many of the carotenoids and phytochemicals is their role as antioxidants, which are scavengers of particles known as oxygen-free radicals (also sometimes called oxidants). These chemically active particles are by-products of many of the body's normal chemical processes. Their numbers are increased by environmental assaults, such as smoking, chemicals, toxins, and stress. In higher levels, oxidants can be very harmful in the following way:

They can damage cell membranes and interact with genetic material, possibly contributing to the development of a number of disorders including cancer, heart disease, cataracts, and even the aging process itself.
Oxygen-free radicals can also enhance the dangerous properties of low-density lipoprotein (LDL) cholesterol, a major player in the development of atherosclerosis.

Description of Antioxidants and Warnings on High-Dose Supplements. Antioxidant vitamins (A, C, and E), carotenoids, and many phytochemicals can neutralize free radicals. Unfortunately, although it is clear that vitamins are required to prevent deficiency diseases, high doses of vitamin C, vitamin E, and beta carotene supplements may also have pro-oxidant effects, which can be harmful in patients with cancer. In these people, high doses of antioxidant vitamins may actually protect cancer cells just as they do healthy cells.

The strongest evidence on negative effects to date comes from studies reporting an increase in lung cancer and overall mortality rates among smokers who took beta carotene supplements. In determining reasons for this disturbing effect, one animal study suggested that beta carotene increased enzymes in the lungs that actually promote cancerous changes. One study also reported a higher risk for cancer in male smokers who took multivitamins plus A, C, or E.

Some evidence also indicates that high doses of vitamin C may speed up atherosclerosis, or hardening of the arteries. In one study, women with heart disease who took antioxidant vitamins had a higher risk for heart attack or death than those who didn't take one.

Another study also reported a higher incidence and greater severity of respiratory infections in older adults who took 200 mg of vitamin E daily. Some researchers speculate that certain immune factors generate oxidants to fight bacteria. This antioxidant vitamin, then, may block that action. Research published in 2005 suggests that those who take large amounts of vitamin E (1,500 IU/day) may slightly increase their risk for heart failure and death, but this evidence is not considered conclusive. Further study is necessary.

Vitamins and Heart Protection.

Antioxidant Vitamins A, C, and E. Deficiencies in vitamins A, C, E, and beta carotene have been linked to heart disease. All of these nutrients have antioxidant effects and other properties that should benefit the heart. A study in patients with heart failure has shown that vitamin C can work with dobutamine, a powerful intravenous medication, to strengthen the heart’s ability to contract following a heart attack. In fact, a 2005 study has found that taking high doses of vitamin E is associated with an increased risk of heart failure. In 2007, the Women’s Antioxidant Cardiovascular Study failed to find that vitamins C, E, and beta carotene could reduce the risk of heart attack, stroke, need for revascularization, or cardiovascular death in women. According to the U.S. Preventive Service Task Force, evidence is insufficient to confirm or refute the benefits of supplements of any of these vitamins in protecting against heart disease.
Folate and B12 Vitamins. Deficiencies in the B vitamins folate (known also as folic acid) and B12 have been associated with elevated blood levels of homocysteine, an amino acid that has been associated with a higher risk for heart disease, stroke, and heart failure. One study, reported lower failure rates after heart surgery in patients who took folic acid and vitamins B12 and B6. And a major 2002 study suggested that lowering homocysteine levels with folic acid would reduce the risk for heart disease by 16% and stroke by 24%. However, a 2007 trial in adults with stable coronary artery disease found that lowering homocysteine levels 33% with B vitamins and folic acid had no effect on arterial inflammation, meaning that lower levels were unlikely to offer protection against heart attack or stroke. More evidence is needed to determine whether homocysteine plays a causal role in cardiovascular disease and whether the B vitamins are protective. Folate improves blood flow through the arteries, which may be important for the heart, regardless of its effect on homocysteine. Although people with high levels of homocysteine are prone to damaging blood clots in their arteries and veins, a 2007 study found that lowering homocysteine with folic acid and other B vitamins does not reduce the incidence of blood clots in the peripheral veins (deep venous thrombosis).
Niacin. Niacin (vitamin B3) is used for lowering unhealthy cholesterol levels. Although vitamin B3 is available over the counter, it can have significant side effects. A physician should prescribe niacin in order to ensure its safety and effectiveness. [See In-Depth Report #23, Cholesterol.]

Carotenoids and Heart Protection. Studies have reported that a diet high in fruits and vegetables containing beta carotene, lycopene, and other carotenoids may reduce the risk of heart attack. A small Finish study found that a diet high in tomatoes reduced total cholesterol and LDL ("bad") cholesterol. Diets low in lycopene (particularly from tomatoes) were associated with a significantly higher risk of heart disease and stroke.

Phytochemicals and Heart Protection. Several phytochemicals are associated with heart protection.

Flavonoids. Certain flavonoids, found in both black and green tea, dark chocolate, onions, red wine or red grape juice, and apples, appear to be strongly heart protective. In one study, people who consumed the most flavonoids in foods had a 20% lower risk for heart disease than those with low consumption. Flavonoids may protect against damage done by cholesterol and help prevent blood clots. A number of studies have now reported heart protection from the flavonoid catechin, which is found in both black and green tea. The flavonoid resveratrol, which is found in grape skin, appears to be responsible for the well-known heart protective effects in red wine and purple grape juice.
Organosulfurs. Organosulfurs found in onions and garlic have been under investigation for possible beneficial effects on cholesterol levels. One study reported an association between taking garlic capsules and significantly lower cholesterol-build up in the arteries of older women but not in older men. In the study, daily garlic supplements dramatically reduced the build-up of newly formed plaque in the arteries, while having much less effect on older, harder plaque deposits. Garlic supplements for cardiovascular disease may be most beneficial when used during earlier years among men and later years among women.
Isoflavones. Soy protein is the most studied source of isoflavones (known as phytoestrogens, or plant estrogens). Not all studies are consistent, but the majority has shown an improvement in at least one of the cholesterol components in people who consumed at least 25 grams of soy protein. A 2007 meta-analysis of all soy protein studies performed from 1990 - 2006 found that soy protein significantly decreased total cholesterol and LDL cholesterol, but had no effect on HDL or triglycerides. The effect was particularly evident in people with hypercholesterolemia. A 2007 study found that 12 weeks of soy supplement lowered total cholesterol and LDL levels in both Caucasian and African-American postmenopausal women. Soy may also reduce other heart risk factors, at least in certain populations. For example, in one 2002 study, soy was beneficial for controlling blood sugar and lowering LDL in postmenopausal women with type 2 diabetes. In a 2007 study of overweight men and postmenopausal women, soy protein reduced blood pressure and arterial stiffness. In another study, soy protein was associated with lower systolic blood pressure in men. The best sources are soy products (tofu, soy milk) or whole soy protein. Powdered soy protein that contains at least 60 mg of isoflavones may provide similar benefits.
Sterols. The plant sterols, including sitosterol, are also proving to be potent cholesterol fighters by blocking the absorption of cholesterol in the intestine. Sitostanol, a derivative of sitosterol, is being used in new margarine products to lower cholesterol levels. Sterols and stanols are now found in breads, cereals, yogurt, and fruit juices.

A healthy diet rich in fruits and vegetables and low in salt and saturated fats may significantly lower the risk for a first stroke, perhaps by helping to protect against high blood pressure -- a major risk factor for stroke.

Vitamins and Stroke Protection. The effects of antioxidant vitamins and carotenoids on stroke, dementia, or both are being studied. Studies are conflicting, however. A 2007 study of 8,171 women with cardiovascular disease reported that vitamins C, E, and beta carotene offered no protection against heart attack and stroke.

The B vitamin folate (usually in the form of folic acid) may protect against stroke. However, exactly which people benefit from this therapy has yet to be determined. Studies have suggested that people who have higher blood levels of folate have a lower than average risk for stroke. Its primary benefit in this case appears to be to reduce levels of homocysteine, an amino acid that has been strongly linked to an increased risk of coronary artery disease, stroke, and Alzheimer's disease. A 2007 meta-analysis of 8 trials found that folate supplements decreased homocysteine 20% and lowered stroke risk 18%. Interestingly, lowering homocysteine with folic acid and B vitamins had no effect on heart attack, strokes, amputations, need for dialysis, or death in patients with chronic or end-stage kidney disease.

Carotenoids and Stroke Protection. Some, but not all, studies have reported a lower risk of stroke from carotenoids, including beta carotene and lycopene.

Many fresh fruits and vegetables contain chemicals that may fight many cancers, including lung, breast, colon, and prostate cancers. Examples of important cancer fighting foods include the following:

Cruciferous vegetables (such as cabbage, Brussels sprouts, and broccoli)
Tomatoes (which contain lycopene)
Carrots (which contain alpha carotene)

Some evidence suggests that antioxidants may enhance the anticancer effects of chemotherapy. In multiple studies, patients who maintained their antioxidant levels were better able to withstand the high stress caused by chemotherapy or radiation therapy compared to those with low antioxidant levels. Antioxidant nutrients that may help reduce the side effects of chemotherapy include vitamins E and C, beta carotene, genistein and daidzein (isoflavones found in soy), and quercetin (found in red wine an purple grape juice).

Any protective effects of vitamins or specific phytochemical against cancer, however, appear to depend on the cooperative effort among them. Individual supplements of any vitamin or food chemical have not as yet shown any benefits.

Additionally, certain supplements may actually encourage tumor growth, particularly when taken in large amounts. Two 2007 studies found a connection between folate supplements and colorectal cancer. In one study, which was designed to evaluate the benefits of folic acid in patients who had previous colorectal adenomas (precancerous polyps), the researchers instead found that folic acid was associated with a higher risk of having 3 or more adenomas and noncolorectal cancers. In another study, it was noted that the downward trend in colorectal cancer diagnoses abruptly started to rise in 1996 when mandatory folate enrichment of grains within the U.S. and Canada began. Rates continue to exceed pre-1996 levels. Additionally, a large 2007 National Cancer Institute/AARP study found an increased risk of advanced and fatal prostate cancer in men who took more than 7 multivitamins a week, but no association between multivitamin use and localized prostate cancer.

High consumption of cruciferous vegetables (at least once per week) was associated with lower risk of kidney cancer, and low consumption (less than once per month) of cruciferous vegetables was associated with higher risk of kidney cancer in a multinational 2007 European study. Cruciferous vegetables also appear to offer protection against head and neck cancer resulting from chemical toxins found in cigarettes and alcohol, for example.

Vitamins and Cancer Protection. Because many cancers are thought to be initiated by the effects of oxygen-free radicals on DNA, the antioxidants A, C, and E and beta carotene have been intensively studied. A major study found that men who took selenium for 6 or 7 years reduced their risk of prostate cancer by 52%. Nevertheless, most individual supplements have not been proven to protect against cancer, and high doses may be dangerous.

A 2007 review of the diets of men exposed to asbestos found a decreased risk of prostate cancer associated with increasing intakes of vitamin C-rich vegetables, but not fruits and vegetables high in vitamin A. The chemopreventive role of silymarin (Silybum marianum), found in milk thistle extract, has been extensively studied and has shown anticancer efficacy against various cancers, especially prostate and skin, by inhibiting UVB radiation.

A review of 13 cancer registries found 416,134 cases of skin cancer and 3,776,501 cases of non-skin cancer as a first cancer. Rates from cancer registries in sunny countries (such as Australia and Spain) and less sunny countries (such as Canada and Iceland) were compared. The researchers concluded that vitamin D production in the skin decreases the risk of several solid cancers, especially stomach, colorectal, liver and gallbladder, pancreas, lung, female breast, prostate, bladder, and kidney cancers. The apparently protective effect of sun exposure against second primary cancer is more pronounced after non-melanoma skin cancers than melanoma.

Consumption of aflatoxins, a common fungus-related toxin infecting cereal grains, oil seeds, spices, tree nuts, and the milk of animals fed contaminated feed, is known to cause hepatocellular carcinoma, a deadly form of liver cancer. Rodent studies have shown that phenolic antioxidants, dithiolethiones, isothiocyanates, and triterpenoids may act as chemopreventive agents, dispersing aflatoxins and protecting against hepatocellular carcinoma. Human trials are planned. A similar study found that several isothiocyanates, diallyl sulfide, and polyphenolic compounds can prevent esophageal dysplasia from progressing to squamous cell carcinoma.

A review of all articles on vitamins and cancer published through February 2007 found that multivitamin/mineral supplement use may prevent cancer in individuals with poor or suboptimal nutritional status. One trial on poorly nourished Chinese showed supplementation with combined Beta-carotene, vitamin E and selenium reduced gastric cancer incidence and mortality, and overall cancer mortality. In a French trial, combined vitamin C, vitamin E, beta-carotene, selenium, and zinc reduced cancer risk in men but not in women. With few exceptions, neither beta-carotene nor vitamin E had benefits for preventing cancer. Beta-carotene supplementation increased lung cancer risk in smokers and persons exposed to asbestos.

A 2007 study of nearly 82,000 men and women in Sweden found that high intake of methionine was associated with reduced risk of pancreatic cancer. The same relationship was not seen with vitamin B6 or folate.

Vitamin A, C, and E. Although some studies have reported an association between low blood levels of these antioxidant vitamins and a higher risk for cancer, supplements of vitamins A, C, and E appear to have few advantages in most cases. And there are some studies finding higher cancer risks with high intakes of antioxidants. For example, a 2003 study reported a higher risk in melanoma in people with vitamin-C rich diets. Another study also reported a higher risk for cancer in male smokers who took multivitamins plus A, C, or E. (Vitamin E may be protective against bladder cancer and ovarian cancer.)
Vitamin D. Some studies have suggested that certain vitamin D compounds may inhibit certain cancer cells, specifically prostate cancer, from proliferating. More research is needed. In 2007, the National Cancer Institute confirmed that ultraviolet (UV) radiation exposure may reduce the risk of developing non-Hodgkin lymphoma (NHL), but only in patients with certain variations in the D vitamin receptor gene. A second 2007 study found that variations in this gene increase the risk of diffuse large B-cell lymphoma. A 2007 prospective analysis of 31,500 women in the Women’s Health Study evaluated calcium and vitamin D intake. The researchers found a moderately lower risk of premenopausal, but not postmenopausal, breast cancer with higher intakes of total calcium and vitamin D. A 2007 review of breast cancer cases reported in Ontario, Canada, found reduced breast cancer risks were associated with increasing sun exposure in women ages 10 - 19, less evidence for associations in women ages 20 - 29, and no evidence for ages 45 - 54. Researchers concluded that sun exposure earlier in life, particularly during breast development, may be key in the connection between vitamin D exposure and breast cancer risk.
Folic acid and B12. These B vitamins convert the amino acid homocysteine to methionine, a substance that helps prevent cells from becoming malignant. Folic acid may provide some protection against cervical and colon cancer. One small study showed a reduction of lung cancer cells in smokers taking folic acid and vitamin B12, but the study was very small, of short duration, and other factors might have biased the results. Still another study reported that folic acid may reduce the risk for breast cancer among women who regularly drink alcohol. (In the study, folic acid had no other effect on breast cancer.)

In 2006, a study for the National Institutes of Health reviewed randomized trials evaluating the effectiveness and safety of multivitamin and mineral supplements in preventing cancer and chronic disease. The studies had mixed results, and some supplements reduced cancer rates in certain populations. However, the reviewers concluded that current evidence is not sufficient to determine whether multivitamin and mineral supplements may prevent cancer and chronic disease.

Carotenoids and Cancer Protection. A number of studies have reported that fruits and vegetables rich in carotenoids are associated with protection against many cancers. Lycopene, found in tomatoes, may have particular value in protection against prostate, colon, lung, and bladder cancer. A 2005 study found that in one out of four men with genetic variations that cause them to be more sensitive to oxidative stress, supplementation with selenium, vitamin E, and lycopene significantly reduces the risk of prostate cancer. Individual supplements, however, do not offer any advantage. In fact, evidence now strongly suggests that beta carotene supplements increase the risk for lung cancer in smokers and people exposed to asbestos

Phytochemicals and Cancer Protection. The following phytochemicals appear to have cancer-protecting properties.

Isothiocyanates. Isothiocyanates and sulforaphane, found in cruciferous vegetables, may block the effects of carcinogens and suppress tumor growth. In one study, for example, women with the highest consumption of cruciferous vegetables had a 24% lower risk of breast cancer than women with the lowest consumption.
Isoflavones. Isoflavones, found in soy beans and flax seed, behave like estrogen in some ways and not in others. Researchers are very interested, then, in their effects on hormone-related cancers, including breast and prostate cancers. Much research has focused on soy. In general, a number of Asian studies have reported an association between a higher intake of soy and a lower incidence of reproductive and breast cancers. The effects of phytoestrogens, however, in all women are far from settled. Some evidence suggests the genistein in soy may have properties that are protective against lung cancer. Nonfermented soy products (tofu, soy milk) also may protect against stomach cancer, while fermented soy products (miso, soy paste) appears to increase the risk.
Organosulfurs. The organosulfur compounds found in the onion and garlic family may have very potent properties in suppressing or blocking carcinogenic substances. A 2007 study found that synthetic organosulfur compounds act as selective inhibitors of growth in breast cancer cells. Studies indicate that people who regularly consume fresh or cooked garlic have about half the risk of developing stomach cancer and two thirds the risk of colorectal cancer as people who eat little or no garlic. One possible explanation for garlic's anti-cancer effect in the stomach is its antibacterial action against H. pylori, which can promote stomach cancer. Taking garlic supplements, however, did not offer these benefits.

It should be noted that studies on the health benefits of vitamins and minerals have some important limitations. Some are held to rigorous standards, while others are not. In most cases, the results of existing research are complex, as they can easily be complicated by factors such as diet, exercise, the presence of healthy or unhealthy lifestyle behaviors, environmental factors, and more.


Disease or Condition	Vitamins	Carotenoids, Phytochemicals, and Healthy Foods
Alzheimer's Disease	Vitamin E. Some reports, including a large 2002 population study, have suggested that vitamin E intake, from food or supplements, may protect against mental decline. (One study suggested that the vitamin protected only those who carried the apoE4 gene. No strong evidence to date has found any protection from antioxidant supplements.) Some studies performed since 2002 challenge this finding, while others agree with it. B Vitamins. Some studies suggest that deficiencies of the B vitamins B6, B12, and folate may be a risk factor for Alzheimer' diseases, possibly because deficiencies elevate homocysteine levels, which some research now associated with a higher risk for Alzheimer's disease. Of these, folates may offer the best protection. In 2007, researchers at Tufts-New England Medical Center reviewed all human studies on folate, vitamin B-6, vitamin B-12, and cognitive function in the elderly conducted between 1966 and November 2006. Six of 10 folate studies reported a significant association between low baseline blood folate concentrations and poor cognitive test performance; 4 of 9 folate studies found associations between low blood folate concentrations and increased prevalence of Alzheimer's disease. No association between vitamin B-6 and vitamin B-12 blood concentrations and cognitive-test performance or Alzheimer's disease was seen, and B-vitamin dietary intake was not associated with cognitive function. Although the majority of studies indicated that low blood folate concentrations predicted poorer cognitive function, data are not solid, due to variations in the way the studies were conducted and lack of agreement on what constitutes a low B-vitamin status.	According to several studies, eating plenty of darkly colored fruits and vegetables may slow brain aging. The estrogen-like properties in isoflavones are of interest in the study of Alzheimer's disease. Animal studies suggest that soy might be protective against AD, particularly in postmenopausal women. Of some concern, however, were one population and a few animal studies suggesting that soy intake may pose a risk for greater mental decline among older men. More research is needed to confirm the effects of soy on the aging brain and to determine if there are gender differences.
Infectious Disease	Studies are mixed whether vitamin supplements protect against upper respiratory infections. Large doses of vitamin C, for example, may help reduce the duration of a cold, but they do not appear to protect against one in the first place, even after exposure to a cold virus. Two studies in 2002 on multivitamins reported opposite results, with one finding fewer infections and one finding no difference. It is possible that vitamin C or multivitamin supplements may be helpful in specific people, such those who are vitamin deficient or have medical problems that impair their immune systems. A review of all studies on vitamin C and pneumonia prevention found only 1 placebo-controlled, randomized trial conducted in an English boarding school during World War II. The trial found a statistically significant (80% or greater) reduction in pneumonia incidence among boys consuming vitamin C. Two less-well-constructed trials arrived at the same conclusion. Therapeutic trials were even scarcer. Only one randomized, double-blind, placebo-controlled study of vitamin C for treatment of pneumonia was found. In this trial, elderly patients given vitamin C had lower mortality and respiratory symptom scores. However, the benefits were restricted to the sickest patients. One other trial of adults in the former Soviet Union found a dose-dependent reduction in the time to recover with two vitamin C doses. One 2007 study on vitamin D found that a single dose by mouth of this vitamin might prevent healthy individuals from activating the bacterium that causes tuberculosis in patients who harbor the infection. Studies on vitamin E specifically have been mixed. A 2002 study, in fact, reported a higher incidence and greater severity of respiratory infections in older adults who took 200 mg of vitamin E daily. However, a 2004 clinical trial conducted among elderly nursing home residents found that daily supplementation with 200 IU of vitamin E did provide protection from upper respiratory infections, especially the common cold. At present, there is not enough evidence to recommend vitamin E for infection prevention. Diarrhea is a worldwide problem, particularly in developing countries and those with poor sanitation. Taking supplements with B-complex vitamins, vitamin C, vitamin E, and selenium may reduce the risk of diarrhea, depending upon the organism that causes the disease. Meanwhile, iron supplements appear to increase the risk of infection from organisms that cause diarrhea. Vitamin A has not been shown to prevent diarrhea. Urinary tract infections (UTIs) may affect as many as 25% of pregnant women. A 2007 study found that women who took vitamin C (100 mg) for 3 months had significantly fewer UTIs than women who did not take vitamin C supplements. Rotavirus is a common cause of acute gastric pain in children under age 5. A 2007 study showed that the high amount of isoflavones found in soy-based infant formula can help prevent rotavirus infection.	Lycopene, found in tomatoes, appears to have properties that protect infection-fighting white blood cells. Saponins extracted from ginseng and allicin (found in garlic) have properties that boost the immune system. Both ginseng and garlic have long been traditionally used for their health benefits.
Asthma	Vitamin C from diet has been associated with lower risk for asthma. In one study, some people with exercise-induced asthma benefited from taking vitamin C one hour before strenuous physical activity. In a 2007 study, taking 1,500 mg supplements of vitamin C for 2 weeks helped prevent exercise-induced airway narrowing in patients with asthma.	Flavonoids found in apples and red wine may help lower the risk for asthma. Some evidence indicates that a low dietary intake of antioxidant nutrients could increase the risk for lung damage. Such nutrients should be obtained from fresh, deep green and yellow-orange fruits and vegetables. A 2007 study found low blood lycopene levels in people with asthma. Increasing lycopene- and vitamin A-rich foods may help raise lycopene levels.
Eye Disorder	Cataracts and Macular Degeneration. Oxygen-free radicals play a role in cataract formation and age related macular degeneration, the most common cause of irreversible blindness in the elderly. Bilberry (Vaccinium myrtillis), which contains powerful anthocyanins, is widely used to prevent macular degeneration. Low levels of vitamin C in the lens of the eye have been particularly strong predictors of cataracts. People with cataracts are frequently deficient in vitamin A, the carotenes, lutein, and zeaxanthin. Studies on protection against cataracts using antioxidant supplements have been mixed, including two identically conducted studies that reported opposite results. Vitamin C currently has the strongest evidence for protection, but even with this antioxidant studies are not consistent. A combination of zinc and antioxidants, including vitamin C and E, may slow the progression of macular degeneration. (Vitamin E alone does not appear to be protective.) Glaucoma. Although no evidence exists that antioxidants will prevent glaucoma, some studies reported an association between vitamin E and improved visual fields in patients with glaucoma.	Several studies report that the consumption of antioxidant-rich foods is associated with a decreased risk for cataracts. Carotenoids, especially lutein, lycopene, and zeaxanthin, are especially eye-protective and may help prevent cataracts and macular degeneration. The National Eye Institute in 2007 suggested that people with intermediate- or advanced macular degeneration in one eye may want to take a vitamin formula shown to reduce the risk of macular degeneration in the other eye by 25%. The formula contains vitamin C, vitamin E, beta-carotene, and zinc. They also suggest that a diet high in lutein and zeaxanthin may help reduce the risk of advanced age-related macular degeneration. Several studies report that the consumption of antioxidant-rich foods is associated with a decreased risk for cataracts. Carotenoids, especially lutein lycopene, and zeaxanthin are especially eye-protective and may help prevent cataracts and macular degeneration.
Skin Disorders and Wrinkles	Topical vitamin A (retinol) has been shown to improve fine wrinkles due to aging, by increasing glycosaminoglycan, which retains water, and increasing collagen production. One small study found that taking a combination of vitamins oral C and E supplements may help reduce sunburn reactions, although the protection is much less than from sunscreens. Taking the vitamins singly did not have any effect. In fact, a 2002 study reported that oral vitamin C had no effect on sunburn reaction. Of concern, in the same study some natural antioxidants in the body were reduced in people who took the vitamin. Also of concern are studies reporting no benefits and possibly harm from topical vitamin C in the form of ascorbyl palmitate, which is soluble in fat. One study reported that older adults had fewer wrinkles if they ate whole grains, fresh fruits and vegetables, and the use of healthy oils (such as olive oil). Diet played a role in improving skin regardless of whether the people in the study smoked or lived in sunny countries.	The following foods and phytochemicals may be especially skin protective: Both green tea and ginger appear to have properties that may provide some protection against skin cancer. Green tea skin care products are now available. The substance silymarin, found in the milk thistle family (which includes artichokes), may inhibit UVB-promoted cancers in animals. In one interesting study, eating garlic protected animals very effectively against UVB damage by interfering with urocanic acid in the skin. Whether these results may apply to humans (and what quantities of garlic might be beneficial) is still unknown.
Osteoporosis	Vitamin D. Vitamin D is the essential companion to calcium in maintaining strong bones. Supplements may be needed for people who have poor exposure to sunlight. It should be noted that diet supplies most people's need and high amounts of vitamin D can be toxic. Of interest: Taking vitamin D supplements does not prevent bone loss in post-menopausal African American women, according to research published in 2005. Further study will be needed to determine whether vitamin D prevents bone loss in women from other ethnic groups. Vitamin K. Studies suggest that vitamin K has properties that protect bone and prevent fracture. Vitamin K2 (menatetrenone), a form of vitamin K, is proving to prevent fractures in people with osteoporosis. Vitamin K affects blood clotting, and supplements are not recommended without specific physician instruction. Vitamin B12. One study reported that in people with osteoporosis and pernicious anemia, taking vitamin B12 (which is used to treat the anemia) also increased bone density. Vitamin C and E. There has been some indication of a positive association between vitamin C and E intake and bone density, although evidence proving actual benefits is weak. Note on Vitamin A. High amounts of dietary vitamin A reduces bone density and may even increase the risk for fracture in both postmenopausal women and men. (A form of vitamin A, retinoic acid, has been found to stimulate bone break down.) Beta carotene does not appear to increase risk. Studies suggest that diets rich in fresh fruits and vegetables (which include those high in potassium and magnesium) reduce elimination of calcium from the body and help preserve bones.	Studies suggest that diets rich in fresh fruits and vegetables (which include those high in potassium and magnesium) reduce elimination of calcium from the body and help preserve bones. Studies are suggesting that isoflavones-rich soy products may actually improve bone density in postmenopausal women. A 2007 study of postmenopausal women in Italy found that 24 months of treatment with genistein plus calcium and vitamin D increased bone density, while women who took calcium and D alone lost bone density. Flavonoids and other compounds in tea may protect the bones.
Menstrual Disorders	Vitamin B6. Limited clinical evidence suggests that vitamin B6 may be beneficial in reducing premenstrual symptoms, including depression. Typically, women take 100 mg per day, although one study suggested that a lower dose (50 mg) may have the same effect. Other preliminary research indicates that women who receive the equivalent of 1,200 mg of calcium and 400 IU of vitamin D per day (through food or supplements) have a significantly lower incidence of premenstrual symptoms than women who did not. Vitamin B1. One study reported relief from menstrual pain using vitamin B1 (thiamin). Vitamin E. Several randomized controlled trials have shown that vitamin E significantly improves both physical and emotional premenstrual symptoms. One study reported that high doses of vitamin E helped reduce menstrual cramps. The doses were much higher than those recommended and could possibly increase the risk for bleeding. Although anecdotal evidence reports that vitamin E helps reduce the frequency of hot flashes for menopausal women, there is no clinical evidence to support this claim.

Resources

http://fnic.nal.usda.gov -- The Food and Nutrition Information Center
http://dietary-supplements.info.nih.gov -- Office of Dietary Supplements, National Institutes of Health
www.ars.usda.gov/ba/bhnrc/ndl -- Nutrient Data Laboratory
www.fda.gov -- Food and Drug Administration
www.eatright.org -- The American Dietetic Association
www.acsh.org -- American Council on Science and Health
www.aicr.org -- American Institute for Cancer Research
www.nutritiondata.com -- Information on vitamins and nutrients in foods
www.consumerlab.com -- Independent testing of nutritional supplements' contents and quality
www.usp.org -- US Pharmacopeia
www.herbs.org -- Herb Research Foundation

References

Age-Related Eye Disease Study Research Group, SanGiovanni JP, Chew EY, Clemons TE, Ferris FL 3rd, Gensler G, Lindblad AS, Milton RC, Seddon JM, Sperduto RD. The relationship of dietary carotenoid and vitamin A, E, and C intake with age-related macular degeneration in a case-control study: AREDS Report No. 22. Arch Ophthalmol. 2007;125(9):1225-1232.

Ambrosini GL, de Klerk NH, Fritschi L, Mackerras D, Musk B. Fruit, vegetable, vitamin A intakes, and prostate cancer risk. Prostate Cancer Prostatic Dis. 2007 May 22; [Epub ahead of print]

Aubertin-Leheudre M, Lord C, Khalil A, Dionne IJ. Six months of isoflavone supplement increases fat-free mass in obese-sarcopenic postmenopausal women: a randomized double-blind controlled trial. Eur J Clin Nutr. 2007 Feb 21; [Epub ahead of print]

Bermudez Y, Ahmadi S, Lowell NE, Kruk PA. Vitamin E suppresses telomerase activity in ovarian cancer cells. Cancer Detect Prev. 2007;31(2):119-28. Epub 2007 Feb 28.

Bodnar LM, Catov JM, Simhan HN, Holick MF, Powers RW, Roberts JM. Maternal vitamin d deficiency increases the risk of preeclampsia. J Clin Endocrinol Metab. 2007 ;92(9):3517-22. Epub 2007 May 29.

Clements RH, Katasani VG, Palepu R, Leeth RR, Leath TD, Roy BP, Vickers SM. Incidence of vitamin deficiency after laparoscopic Roux-en-Y gastric bypass in a university hospital setting. Am Surg. 2006;72(12):1196-202.

Coull DB, Tait RC, Anderson JH, McKee RF, Finlay IG. Vitamin B12 deficiency following restorative proctocolectomy. Colorectal Dis. 2007;9(6):562-566.

Dietary Guidelines for Americans 2005. Dept of Health and Human Services, US Dept of Agriculture. Accessed 10/3/2007.

Fischer Walker CL, Black RE. Micronutrients and diarrheal disease. Clin Infect Dis. 2007;45 Suppl 1:S73-S77.

Glynn RJ, Ridker PM, Goldhaber SZ, Zee RY, Buring JE. Effects of random allocation to vitamin E supplementation on the occurrence of venous thromboembolism: report from the Women's Health Study. Circulation. 2007;116(13):1497-503.

Headstrom PD, Rulyak SJ, Lee SD. Prevalence of and risk factors for vitamin B(12) deficiency in patients with Crohn's disease. Inflamm Bowel Dis. 2007 Sep 20; [Epub ahead of print]

Inderjeeth CA, Glennon D, Petta A, Soderstrom J, Boyatzis I, Tapper J.Vitamin D and muscle strength in patients with previous fractures. N Z Med J. 2007;120(1262):U2730.

Ishihara J, Otani T, Inoue M, Iwasaki M, Sasazuki S, Tsugane S; Japan Public Health Center-based Prospective Study Group. Low intake of vitamin B-6 is associated with increased risk of colorectal cancer in Japanese men. J Nutr. 2007;137(7):1808-1814.

J.G. Ray, C. Kearon, Q. Yi, P. Sheridan, and E. Lonn, for the Heart Outcomes Prevention Evaluation 2 (HOPE-2) Investigators. Randomized Trial of Homocysteine-Lowering Therapy and Risk for Venous Thromboembolism. Ann Intern Med. 2007;146(11):761-767.

Kitchin B, Morgan SL. Not just calcium and vitamin D: other nutritional considerations in osteoporosis. Curr Rheumatol Rep. 2007;9(1):85-92.

Kune G, Watson L. Colorectal cancer protective effects and the dietary micronutrients folate, methionine, vitamins B6, B12, C, E, selenium, and lycopene. Nutr Cancer. 2006;56(1):11-21.

Lim MR, Huang RC, Wu A, Girardi FP, Cammisa FP Jr. Evaluation of the elderly patient with an abnormal gait. J Am Acad Orthop Surg. 2007;15(2):107-117.

Martin H, Lindblad B, Norman M. Endothelial function in newborn infants is related to folate levels and birth weight. Pediatrics. 2007;119(6):1152-1158.

Mason JB, Dickstein A, Jacques PF, Haggarty P, Selhub J, Dallal G, Rosenberg IH. A temporal association between folic acid fortification and an increase in colorectal cancer rates may be illuminating important biological principles: a hypothesis. Cancer Epidemiol Biomarkers Prev. 2007;16(7):1325-1329.

Nardin RA, Amick AN, Raynor EM. Vitamin B(12) and methylmalonic acid levels in patients presenting with polyneuropathy. Muscle Nerve. 2007;36(4):532-535.

Ochoa-Brust GJ, Fernández AR, Villanueva-Ruiz GJ, Velasco R, Trujillo-Hernández B, Vásquez. Daily intake of 100 mg ascorbic acid as urinary tract infection prophylactic agent during pregnancy. Acta Obstet Gynecol Scand. 2007;86(7):783-787.

Parekh N, Chappell RJ, Millen AE, Albert DM, Mares JA. Association between vitamin D and age-related macular degeneration in the Third National Health and Nutrition Examination Survey, 1988 through 1994. Arch Ophthalmol. 2007;125(5):661-669.

Pham DQ, Plakogiannis R. Vitamin E supplementation in Alzheimer’s disease, Parkinson’s disease, tardive dyskinsia, and cataract: Part 2. Ann Pharmacother. 2005;39(12): 2065-2072.

Riccioni G, Bucciarelli T, Mancini B, Di Ilio C, Della Vecchia R, D'Orazio N. Plasma lycopene and antioxidant vitamins in asthma: the PLAVA study. J Asthma. 2007;44(6):429-432.

Ronnenberg AG, Venners SA, Xu X, Chen C, Wang L, Guang W, Huang A, Wang X. Preconception B-vitamin and homocysteine status, conception, and early pregnancy loss. Am J Epidemiol. 2007;166(3):304-12. Epub 2007 May 2.

Sahin M, Tutuncu NB, Ertugrul D, Tanaci N, Guvener ND. Effects of metformin or rosiglitazone on serum concentrations of homocysteine, folate, and vitamin B12 in patients with type 2 diabetes mellitus. J Diabetes Complications. 2007;21(2):118-123.

Tamori A, Habu D, Shiomi S, Kubo S, Nishiguchi S. Potential role of vitamin K(2) as a chemopreventive agent against hepatocellular carcinoma. Hepatol Res. 2007;37 Suppl 2:S303-307.

Tecklenburg SL, Mickleborough TD, Fly AD, Bai Y, Stager JMAscorbic acid supplementation attenuates exercise-induced bronchoconstriction in patients with asthma. Respir Med. 2007;101(:1770-1778.

Triantafyllou NI, Kararizou E, Angelopoulos E, Tsounis S, Boufidou F, Evangelopoulos ME, Nikolaou C, Vassilopoulos D. The influence of levodopa and the COMT inhibitor on serum vitamin B12 and folate levels in Parkinson's disease patients. Eur Neurol. 2007;58(2):96-99.

Vagianos K, Bector S, McConnell J, Bernstein CN. Nutrition assessment of patients with inflammatory bowel disease. J Parenter Enteral Nutr. 2007;31(4):311-319.

Velasquez MT, Bhathena SJ. Role of dietary soy protein in obesity. Int J Med Sci. 2007; 4(2):72-82.

Wang Y, Hodge AM, Wluka AE, English DR, Giles GG, O'sullivan R, Forbes A, Cicuttini FM. Effect of antioxidants on knee cartilage and bone in healthy, middle-aged subjects: a cross-sectional study. Arthritis Res Ther. 2007;9(4):R66 [Epub ahead of print]

Wang X, Qin X, Demirtas H, Li J, Mao G, Huo Y, Sun N, Liu L, Xu X. Efficacy of folic acid supplementation in stroke prevention: a meta-analysis. Lancet. 2007;369(9576):1876-1882.

Weingärtner J, Lotz K, Fanghänel J, Gedrange T, Bienengräber V, Proff P. Induction and Prevention of Cleft Lip, Alveolus and Palate and Neural Tube Defects with Special Consideration of B Vitamins and the Methylation Cycle. J Orofac Orthop. 2007; 68(4):266-277.

Wierzbicki AS. Homocysteine and cardiovascular disease: a review of the evidence. Diab Vasc Dis Res. 2007;4(2):143-50.

Zeisel SH. The fetal origins of memory: the role of dietary choline in optimal brain development. J Pediatr. 2006;149(5 Suppl):S131-136.

Ziaei S, Kazemnejad A, Zareai M. The Effect of Vitamin E on Hot Flashes in Menopausal Women. Gynecol Obstet Invest. 2007;64(4):204-207 [Epub ahead of print]

Zollinger PE, Tuinebreijer WE, Breederveld RS, Kreis RW. Can vitamin C prevent complex regional pain syndrome in patients with wrist fractures? A randomized, controlled, multicenter dose-response study. J Bone Joint Surg Am. 2007;89(7):1424-1431.

Review Date:
10/29/2007
Reviewed By:
Harvey Simon, MD, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital.

A.D.A.M. Copyright

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