Sports Drinks Based On Biased Evidence?

A writer in the July 19 Toronto Sun notes that, just days before the 2012 Summer Olympics was set to begin in London, the British Medical Journal (BMJ) published a group of articles that suggest the science behind sports drinks is biased and inconclusive.

Until the 1970s, marathon runners were advised to avoid drinking anything at all during competition for fear it would slow them down. Today, everyone is encouraged to hydrate before, during and after exercise, and sports-drink companies frequently sponsor elite sporting events, including the upcoming games in London.

In “The truth about sports drinks, ” the Toronto Sun quotes BMJ investigations editor Deborah Cohen who found that sports-drink companies sponsored scientists who then went on “to develop a whole area of science dedicated to hydration”—and who happen to advise sports medicine organizations, whose guidelines have trickled down to become accepted health advice.

Cohen notes that The American College of Sports Medicine accepted a $250, 000 donation from Gatorade in 1992, and four years later, the college developed new guidelines adopting a “zero % dehydration” mantra that advised athletes to “drink as much as tolerable.” The guideline came out of a 1993 roundtable meeting supported by Gatorade.

In 1993, a group of experts led by a sport and exercise nutrition professor who was a member of the Gatorade Sports Science Institute developed a consensus statement about the dangers of dehydration at a meeting funded by Isostar, a sports drink then owned by the drug company Novartis. “There is a need to make athletes more aware of the dangers of dehydration and of the importance of adequate fluid intake, ” the experts wrote in an article published in the British Journal of Sports Medicine. “Water is not the best fluid for rehydration, either during or after exercise.”

Cohen notes that, in another BMJ article, researchers at the Centre for Evidence-Based Medicine at the University of Oxford examined the claims made about sports-enhancement products, including sports drinks, and reviewed 1, 035 websites. They identified 431 performance-enhancing claims for 104 different products and found that “there is a striking lack of evidence to support the vast majority of sports-related products that make claims related to enhanced performance or recovery.” Only 3 of the 74 studies they examined were found to be “of high quality and at low risk of bias.”

In another article evaluating current hydration recommendations, the authors found that “drinking according to the dictate of thirst throughout a marathon seems to confer no major disadvantage over drinking to replace all fluid losses, and there is no evidence that full fluid replacement is superior to drinking to thirst.”