Do caffeinated beverages cause dehydration?

Myth 35: Drinking tea causes dehydration.
What Dietitians of Canada says:
“It’s a popular belief that tea is dehydrating because it has caffeine, but the level of caffeine you get from drinking moderate amounts of tea, even strong tea, doesn’t dehydrate you. Tea is actually 99.5 percent water and counts towards your fluid intake for the day, so it can help keep you hydrated… How or cold, tea is also hydrating and, with no added sugar, is calorie-free and tastes great.”
What I say:
Interesting how this myth centres on tea, no mention of coffee, and Lipton is one of the Nutrition Month sponsors this year. Coincidence? I think not. Anyway… Setting that aside, this statement by DC is all true. It is a common misconception that coffee and tea are dehydrating. Coffee and tea actually both count towards your daily total fluid intake. You can drink up to about 6 cups of coffee before the caffeine is going to have a dehydrating effect on you. Coffee and tea also have numerous health benefits. Coffee may have anti-cancer properties (caffeinated coffee has been linked to reduced rates of liver, colon, breast, and rectal cancers). Coffee may protect men, but not women, against Parkinson’s disease, and it may also reduce your risk of type 2 diabetes. Health Canada has endorsed three health benefits from drinking tea: tea is a source of antioxidants, drinking tea can increase alertness, and tea may help maintain or support cardiovascular health. Health Canada tends to err on the side of caution so there may indeed be more health benefits associated with drinking tea. It’s important to note that these benefits are associated with black coffee and tea with nothing added. While you may still see health benefits from drinking tea or coffee with added milk or milk alternative you’re likely to see more negative health consequences than benefits if you’re drinking tea or coffee loaded with cream and sugar and especially if you’re drinking desserts masquerading as coffee as you see at many coffee shops.

Caffeine Champion

I recently had a conversation that irked me. Someone I had just met said that he was going to go home and have some green tea to wake up. I expressed surprise as green tea does not have a particularly high caffeine content. He insisted that it has more than coffee. My friend piped up with the fact that I’m a dietitian. He said he has friends who work in tea houses. I countered with the fact that I used to manage a small chain of coffee shops. He said “I bet you didn’t sell a lot of tea.” I said “touche” and let it go as clearly this was not an argument I was going to win. Anyway… Just in case you’re wondering… The caffeine content of tea and coffee can vary considerably, mostly due to the method of preparation. On average though, coffee is the caffeine leader at roughly 95 mg per serving (which is a tiny 8 oz). In close second is black tea with an average 88 mg per 8 oz. Coming in third is green tea, at a mere 32 mg per 8 oz. Vindication. Regardless of caffeine content, there are different health benefits related to each when consumed in moderation, and detrimental effects when consumed in excess.