Most American children and teenagers aren't drinking enough fluids, and that's leaving them mildly dehydrated, according to a new study. In fact, one-quarter of a broad cross-section of children ages 6 to 19 apparently don't drink any water as part of their fluid intake.
The Harvard scientists who turned up the finding were initially looking into the consumption of sugary drinks in schools and looking for ways to steer children toward water instead — a much healthier beverage.
Along the way, they noticed that "kids weren't really drinking that much fluid," says postdoctoral researcher Erica Kenney at Harvard's T.H. Chan School of Public Health. She wondered if that was posing any problems for them.
So she and her colleagues dug into data from the National Health and Nutrition Examination Survey, which gathers an amazing amount of information from study participants, including chemical tests of their urine. Those urine tests reveal whether people are adequately hydrated — people who don't take in enough water have darker, saltier urine.
The researchers report Thursday in the American Journal of Public Health that more than half of the several thousand students studied between 2009 and 2012 were at least a bit dehydrated.
"This doesn't mean we're saying kids are dropping like flies or that they're very seriously dehydrated and need to go to the hospital or anything like that," Kenney says. But even mild dehydration can affect children's fatigue levels, mood and possibly their ability to learn, she says.
"It was astounding to me," Kenney says, that so many children said they drink no water at all. "And even among the kids who were drinking water — they weren't drinking very much of it."
The Institute of Medicine says children and teenagers should consume about two to three quarts of water a day (1.7 to 3.3 liters, the IOM says), depending on age, size and sex. Adolescent boys generally need to drink more water than girls do, research suggests.
"That's total water, so that can be from any beverages — any water that's in your food like soups, juicy fruits and vegetables, things like that," Kenney says.
And while kids fall short, dehydration is an easy problem to fix: Just get them to drink more water throughout the day. But Kenney says it's not quite as simple as it seems.
Especially in cities, "a lot of schools have struggled with providing tap water to kids because of concerns about older plumbing infrastructure and concerns about lead," she says.
Some schools offer jugs of bottled water, but that's expensive and time-consuming to maintain.
Kenney says some school programs aimed at reducing consumption of sugary drinks are now making water more accessible and appealing in the cafeteria — adding a soda-fountain style dispenser for water, for example. Those mealtime programs, she says, can help on the dehydration front, as well.