Teenagers are drinking more soft drinks and coffee than they did a decade ago, and with caffeinated products sold in schools, health organizations are urging educators to consider the impact of caffeine on students’ health, behavior, and learning.
Experts say that caffeine can disrupt students’ sleep cycles, cause them to excrete calcium and other necessary minerals through urination, and become nervous and irritable if consumed in large doses.
While some districts, including the Los Angeles and Milwaukee public schools, have banned the sale of sodas, most administrators say they don’t consider the caffeine content of those beverages a problem. Instead, efforts to remove vending machines from schools have centered around concerns over the growing obesity rates among young people.
Health educators say, however, that caffeine is to blame for some behavioral problems in schools. And the kinds of drinks found in most vending machines often contain the stimulant, they point out.
“I think schools should do a better job of explaining what caffeine can do to your body and limiting kids’ access to it,” said Marcia Rubin, the director of research and sponsored programs at the American School Health Association, based in Kent, Ohio.
Instead of allowing soft drink sales, schools should promote the consumption of water, milk, and other dairy products, she said.
“Many high school students drink Mountain Dew or other sodas or even high-energy drinks like Red Bull for breakfast,” said John Fahey, an assistant professor of educational leadership at James Mason University in Harrisonburg, Va., and a former high school principal.
A report issued in 1998 for the Washington-based Center for Science in the Public Interest found that teenagers now drink, on average, twice as much soda as they do milk, and that milk consumption among children overall is falling.
In 1997 alone, nearly 14 billion gallons of soft drinks were sold in the United States, the report said, and teenagers were among its most avid consumers.
The upswing in coffee consumption by teenagers has added to the increased concern, particularly since coffee can have up to five times the amount of caffeine, per ounce, as most soft drinks.
No studies positively link caffeine consumption to hyperactivity. Overuse, however, can interrupt sleep patterns, creating dependency on the stimulant to help fight a cycle of fatigue, experts say.
“One of the reasons students drink so much soda is that it’s a meal supplement,” said Janette Faul, a spokeswoman for Peak Performance, in Manitowok, Wis., a program that works with schools in Wisconsin to encourage better nutrition. “Many students have to get up early to go to school, [and] they’re not hungry when they get up to get to the bus,” she said, “so when they get to school they go to vending machines.”
Most experts generally agree that a safe dose of caffeine is about 200mg to 300mg per day. Health educators say teenagers are drinking, on average, three to four soft drinks a day. A 20-ounce bottle of Classic Coke contains 57mg of caffeine, according to the Center for Science in the Public Interest.
But many students are trying “energy” drinks such as Red Bull, which have higher levels of caffeine. An approximately 8-ounce can of Red Bull, for example, contains 80mg of caffeine.
“There’s a lot of reason to be concerned,” said Margo Wootan, the center’s director of nutrition policy, “because caffeine can cause a lot of problems.”
Caffeine, a mild stimulant, can make people feel more relaxed and alert in small doses. But some studies show that high doses of caffeine can have debilitating effects, including increased heart rate, depression, insomnia, infertility, and increased risk of miscarriage.
“Caffeine acts specifically to affect sleep,” said Mary A. Carskadon, the director of sleep and chronobiology at Bradley Hospital in East Providence, R.I. “It blocks neuroreceptors, preventing sleep, and one of the major problems with teens is that they’re not getting enough [sleep] to begin with.”
Teenagers need at least 9½ hours of sleep a night, she said, but most are actually getting fewer than seven.
And sleep patterns can have a dramatic effect on student behavior and learning. “There is growing evidence that a full night of sleep is required for specific types of learning,” Ms. Carskadon said. “We’ve all had the experience of staying up all night and cramming for a test, but the problem is that it’s a wasted way of learning.
“You may remember for the next day’s exam, but the information doesn’t get consolidated or provide scaffolding for other memory and learning functions.”
David Hattan, a spokesman for the federal Food and Drug Administration, said that while caffeine can potentially have negative effects if a person doesn’t maintain a balanced diet, when it is consumed in moderation it doesn’t pose a significant health risk.
Sean McBride, a spokesman for the National Soft Drink Association, a trade group based in Washington, says that health organizations are being “alarmist.”
The amount of caffeine that can be placed in beverages is strictly monitored, he said, adding that most sodas have only about 3mg per ounce. The federal government allows manufacturers to place up to 6mg of caffeine per ounce in beverages.
While there’s no doubt that soft drink consumption has increased, Mr. McBride said, the U.S. Department of Agriculture’s most recent survey of commonly consumed foods found that only 5 percent of 12- to 19-year-olds were drinking more than three 12-ounce soft drinks a day. The survey also found that 22.5 percent of teenagers did not consume any soft drinks.
But Ms. Faul of Peak Performance maintains that students can gorge on soft drinks, recalling a student from Hartford Union High School in Hartford, Wis.
“We were talking about soda and one girl raised her hand, and she started to tell me about her soda addiction,” Ms. Faul said. “She started to cry as she told me: ‘I drink six Pepsis a day, I’m not eating right, and I have no appetite. All I think about is when I’m going to get my next fix.’”