Does Black Tea Dehydrate You?

One concern regarding black tea and other caffeinated beverages is that they can cause you to lose more water through your urine, ultimately resulting in dehydration. Although large amounts of caffeine can cause dehydration, you are unlikely to become dehydrated by drinking black tea. However, the fluid in black tea may cause you to urinate more.

Dehydration Physiology

Dehydration is a state in which your body does not have as much water as it needs. Dehydration can be caused by not drinking enough water; by excreting too much water via sweat, urine, diarrhea or vomiting; or a combination of both. Signs of dehydration include a dry or sticky mouth, low urine output, sunken eyes, increased thirst, a lack of tears and confusion or lethargy, though the latter two symptoms generally only occur in severe cases.

Black Tea and Caffeine

When you drink black tea, you are also ingesting caffeine. The amount of caffeine in black tea varies depending on the type of tea you drink and its strength. In general, one cup of black tea contains between 40 and 120 mg of caffeine. Decaffeinated black tea still contains some caffeine, but the levels are greatly reduced and are usually in the range of between 2 and 10 mg per cup.

Caffeine and Fluid Loss

Diuretics are substances that increase your urine output, potentially resulting in dehydration. Caffeine is often thought to be a diuretic. However, a study published in a 2005 issue of the "International Journal of Sport Nutrition and Exercise Metabolism" examined the effects of caffeine on fluid balance and kidney function and found that consuming caffeine did not deplete the body of water or increase the amount of urine produced. The maximum caffeine dose in this study was 180 mg. Caffeine only acts as a diuretic if you consume more than 500 to 600 mg a day, MayoClinic.com notes.

Considerations

If you are concerned about becoming dehydrated due to excessive black tea intake or other causes, talk to your doctor. It does not appear that black tea can cause significant dehydration unless you consume vast quantities of this beverage. However, dehydration can be a serious medical problem, so it is always best to err on the side of caution. Too much caffeine can also cause anxiety, tremors, diarrhea and other side effects, so avoid excessive caffeine consumption.