There seems to be universal acceptance these days that drinking more water is good for you.
But Heinz Valtin of Dartmouth Medical School found that there wasn’t really any scientific evidence for this.
And there’s more on the subject here, including, for example, the widely-held belief that we need to drink more because of the dehydrating effects of caffeinated drinks. Extract:
Regular coffee and tea drinkers become accustomed to caffeine and lose little, if any, fluid. In a study published in the October issue of the Journal of the American College of Nutrition, researchers at the Center for Human Nutrition in Omaha measured how different combinations of water, coffee and caffeinated sodas affected the hydration status of 18 healthy adults who drink caffeinated beverages routinely.
“We found no significant differences at all,” says nutritionist Ann Grandjean, the study’s lead author. “The purpose of the study was to find out if caffeine is dehydrating in healthy people who are drinking normal amounts of it. It is not.”
The same goes for tea, juice, milk and caffeinated sodas: One glass provides about the same amount of hydrating fluid as a glass of water. The only common drinks that produce a net loss of fluids are those containing alcohol — and usually it takes more than one of those to cause noticeable dehydration, doctors say.
Many of these reports were published a few years ago, which shows that urban legends can take a long time to die. Or perhaps, if you’re a conspiracy theorist, that the bottled-water industry has a lot to gain by perpetuating them…