Tea is one of the healthiest beverages you can drink. It’s rich in phytonutrients (healthy plant compounds) and like water, it’s calorie-free. But there has been a belief that caffeinated drinks, such as tea, are diuretics.
Diuretics cause you to lose more water from your body. That is, they increase the production of urine, so you’re sprinting more often to the John. But if you’re trying to stay hydrated, you may have been told to avoid drinking tea. A study that led to the belief that caffeinated drinks are diuretics used high-dose caffeine pills. However, a study published in the British Journal of Nutrition tested the effects of black tea which is a more complex substance than pills. Here’s what they found…
The Tea Test
After a 10-hour fast and 24 hours of avoiding all caffeine, alcohol and vigorous exercise, twenty-one healthy resting men consumed 10 cups of caffeinated black tea at regular intervals providing roughly 170 to 250 mg of caffeine. The tea was prepared using tea bags and mixed with 20 ml of low-fat milk.
All food was controlled and they had nothing else to drink during the trial. Every drop of tea going in and every drop going out was measured and examined for color and electrolyte-water balance over a 24-hour period. Blood was sampled at the start of the trial and again at 1, 2, 4, 8, and 12 hours.
The test was repeated with boiled water. And guess what they found? There was absolutely NO significant difference between drinking tea and water on blood and urine values. Black tea had the same hydrating effects as water.
Karen’s Fit Tip: Enjoy your cup of tea and don’t worry about your pee!
Black tea is not significantly different from water in the maintenance of normal hydration in human subjects: results from a randomised controlled trial. British Journal of Nutrition. August 2011.
Originally posted on 2.25.17