How Much Water Do You Need – Is 8 Glasses a Day Enough and Does Tea and Coffee Count?

Do Coffee and Tea Help Meet Your Water Needs?

• Read our expert article on Water

You’ve undoubtedly been told, repeatedly, that coffee, tea or soft drinks don’t count towards your daily hydration goal.

This, at least, is one “fact” that deserves to be retired. Studies have shown that it’s perfectly fine to derive a portion of your daily need for water from these beverages. Even water in food counts towards one’s daily rehydration needs, providing up to 25% of the daily requirement.3 But coffee has caffeine, and caffeine is dehydrating, you argue. Possibly, and if you are drinking coffee for the first time, it may indeed have a slight dehydrating effect on you. But most coffee drinkers are habitual drinkers, and their kidneys have long since adapted to the effects of caffeine. Starbucks patrons, therefore, are not dehydrated by coffee; rather, they are hydrated by it. The same holds true for tea, or any caffeinated beverage.

Since the early 20th century this has been proven repeatedly. For example, in 2000 scientists at the Center for Human Nutrition, in Omaha Nebraska, reported in the reputable Journal of the American College of Nutrition, that caffeine has no adverse effect on hydration among healthy individuals. “Advising people to disregard caffeinated beverages as part of the daily fluid intake is not substantiated by the results of this study,” investigators wrote.4 And lest you feel inclined to stubbornly cling to the oft-repeated caffeine-is-dehydrating mantra, consider this 2003 finding, by British researchers: “Doses of caffeine equivalent to the amount normally found in standard servings of tea, coffee and carbonated soft drinks appear to have no diuretic action…there would appear to be no clear basis for refraining from caffeine containing drinks in situations where fluid balance might be compromised.”5 Yet another recent study tested two sets of similar subjects. On group received a diet with no plain drinking water provided as a beverage choice, while a second group ate the same diet with water included as a beverage choice. There was no difference in hydration between the two groups after three days of consuming the prescribed diet.6

Sweetened and/or carbonated beverages — sodas and soft drinks — are another story. While they provide hydration, they also provide massive amounts of unnecessary, “empty” calories in the form of simple sugars. For this reason alone they should be avoided. Coffee and tea should be enjoyed with gusto, however; both contain bioactive compounds associated with multiple health benefits. Coffee drinking, for instance, has been linked to a lower risk of dementia among the elderly,7 and lower all-cause mortality among adult men and women.8

A large Japanese study published in the European Journal of Epidemiology in 2011, examined coffee consumption among nearly 100,000 adults aged 40-79. The 16-year study found that coffee drinking was actually associated with a lower risk of cancer among women, and fewer deaths from any cause among both sexes.8 Other studies report a decreased risk of type 2 diabetes among coffee drinkers.9, 10

The benefits of drinking green tea are also myriad. Green tea consumption has been linked to a wide array of health benefits, including decreased risk of various cancers, reduced risk of cardiovascular disease and a lower risk of type 2 diabetes and dementia.11, 12