Caffeine and kids: A safe mix?

Information also is lacking on the physiological, psychological and behavioral effects of habitual caffeine use by children. "We can't assume children are small adults. They may have unique responses we don't know about," Temple said.

The FDA limits the caffeine content in soft drinks to 71 milligrams per 12 fluid ounces. But manufacturers often circumvent the limit by calling their products dietary supplements. Some energy drinks contain as much caffeine as five cups of coffee.

Sales of energy drinks grew by 78 percent from 2006 to 2011, according to the market research firm Mintel, and a recent study in the journal Pediatrics found that half of the energy drink market consists of children, adolescents and young adults.

Energy drink consumption has been associated with elevated blood pressure, altered heart rates and severe cardiac events in children and young adults, especially those with underlying cardiac disease, according to a letter sent to the FDA by more than a dozen prominent researchers and scientists. The highest doses have been linked with caffeine intoxication, resulting in a racing heartbeat, vomiting and cardiac arrhythmias.

Dr. Steven Lipshultz, a pediatric cardiologist at the University of Miami, tells parents that young patients with an underlying heart condition should avoid caffeine because it can stimulate the heart. "If you're asking a sick heart to work even harder, it may go into a life-threatening heart rhythm," he said.

Goldberger, an adult cardiologist, downplayed the cardiac risk of energy drinks in his testimony before the Chicago City Council when it considered restricting sales of the products. In 2011 he published research in the American Journal of Medicine that concluded moderate caffeine use was well tolerated in adult patients with known or suspected arrhythmia.

Wheaton mom Nancy VanderMolen said she limits caffeine for her preteen daughter because of the girl's heart condition. But she was disappointed that Wrigley pulled its caffeinated gum off the market because she wanted to try it herself.

"If the packaging is good, people with heart conditions would stay away just as they do from Red Bull," VanderMolen said. "I don't like coffee and need the caffeine boost. I was looking forward to the gum so I could give up soda for good."

That's the sort of customer Roger Sullivan, the founder of Wired Waffles, is targeting. After hearing about a bakery that laced brownies with caffeine, Sullivan created a caffeinated waffle. Later he launched caffeinated maple syrup.

Though the products aren't designed to be eaten together, consuming both would yield 284 milligrams of caffeine — still less than a 16-ounce cup of Starbucks, which has 330 milligrams, Sullivan noted.

Sullivan said he supports full disclosure of caffeine content in drinks and snacks. His products carry a voluntary warning label that says they are not intended for pregnant or nursing mothers, children or people sensitive to caffeine. "I've been very careful to be sure not to use marketing that is aimed at kids," he said.

Once children and teens start consuming caffeine, they often continue for the same reasons as adults.

Morgan Gstalter, 18, of Skokie, said she doesn't like the taste of energy drinks but has been drinking coffee since she was about 10, when her father introduced her to it.

"It was mostly milk and sugar at that point, but as I grew up I started drinking it more and more," said Gstalter, who has contributed to The Mash, a Chicago Tribune Media Group publication for high schoolers.

Now, like many of her peers, she drinks at least one cup a day, occasionally buying an extra coffee in the lunchroom at Skokie's Niles West High School, where she recently graduated.

"Coffee has become such a regular thing in my life now, that I can feel the days when I woke up late and forgot my travel mug," she said. "It cuts back the sleepiness a little, and if I don't have coffee in the mornings I feel sluggish and moody all day."

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