Sunshine is a great source of vitamin D, but if cooler weather or your busy work or school schedule has you spending less time outside, you'll want to make sure you're getting enough from your diet. An adult woman needs five micrograms or 200 International Units (IU) of vitamin D each day, though it is argued that the RDI for women should be 800 to 1,000 IU. The tolerable upper intake level is 50 mcg or 2,000 IU. If you don't get enough, your risk for osteoporosis increases, since this vitamin helps maintain bone strength.

To see what I ate yesterday to reach my daily vitamin D intake, read more.

Salmon, mackerel, tuna, and cod liver oil are excellent sources, but if you don't eat fish, opt for dairy products instead and make sure they are fortified with vitamin D. Two cups of milk contain 200 IU of vitamin D, so if you work that into your diet, you're all set. If you're vegan, you'll probably want to take supplements or look for products such as orange juice or cereals that are fortified with vitamin D.