Why kids don't need sports drinks

In some "healthy" school vending machines across the country, soda is out. But rehydrating, sugar-laden sports drinks are still in.

Often promoted by popular athletes as essential thirst quenchers, sports beverages can be beneficial if they're consumed during or after an intense workout that lasts an hour or more, said Russell Pate, professor of exercise science at the University of South Carolina.

Some research has shown that children will take in more fluids if offered a sports drink rather than water alone.

In school districts such as the Fayette County Public Schools in Lexington, Ky., meanwhile, sports drinks -- along with water and 100 percent juice -- are considered "healthy beverages" in vending machines if they contain less than 10 grams of sugar per serving.

But sports beverages are little more than sugar water with electrolytes, something most children don't need, said registered dietitian Lilian Cheung, a lecturer in the department of nutrition at the Harvard School of Public Health.

Kids get plenty of electrolytes in food. And even after vigorous exercise, water is as good as sports drinks for replenishing fluids while keeping electrolytes balanced, according to a 2006 study in the British Journal of Sports Medicine.

Children's health experts say sports drinks are not just contributing to obesity; they're also hard on the teeth. Research has shown they can do more damage to enamel than carbonated cola products, especially if sipped over long periods of time.

And ultimately, the drinks are unnecessary, said Harvard sociologist Steven Gortmaker, a healthful-eating researcher who has written several studies looking at children's consumption of sugar-sweetened beverages. "Unless they're running marathons, which we do not recommend for kids, water is the best choice for quenching their thirst," Gortmaker said.

If your child won't drink water or has an aversion to school drinking fountains, don't fret. Studies show that when fluid is low, the body stimulates the thirst centers in the brain, and if water is available, kids will drink. And unless a child exercises for more than two hours, no extra calories are needed, said Dr. Joanna Dolgoff, a child and adolescent weight-management expert.

Though it varies by brand, a 20-ounce bottle of a sports drink contains about 10 teaspoons of sugar and 130 calories, more than you may burn during a workout. Drinking just one bottle every day for a year could add 13 pounds, said Dolgoff.