DrSugar is in the house! To celebrate National Coffee Day, she's answering an age-old question about how your cup of java affects your day.
I am confused about coffee. I remember reading somewhere that coffee is only a mild diuretic and doesn't contribute to dehydration. But after I drink a cup of coffee or an espresso drink, my mouth feels dry and I need to pee more frequently. So I am hoping you can clarify this. Is coffee a diuretic? And how exactly do diuretics work? Is coffee dehydrating, or is it the caffeine?
— Confused Coffee Lover
Don't worry, you are not the only one out there confused about coffee! For years, medical experts had been saying that the caffeine in coffee acts as a potent diuretic, which leads to excessive urination resulting in dehydration. But, like you mentioned in your question, recent research has been published on this topic and the results appear to contradict the prior notion about coffee. Most studies have shown that in moderate amounts, the caffeine in coffee only has mild diuretic effects and does not lead to dehydration. To learn why, keep reading.