By Tina Peng

Caffeine is the world’s most common mood-altering drug, and more kids are consuming it in higher quantities. About a third of 12- to 24-year-olds chug energy drinks, which are often marketed to teens. How much is too much? The Food and Drug Administration doesn’t regulate Americans’ caffeine intake, but Health Canada recommends that children ages 4 to 6 ingest no more than 45mg of caffeine a day (one cup of tea or one can of cola); kids ages 7 to 9 no more than 62.6mg, and those ages 10 to 12 no more than 85mg. Teens ages 13 and up should not exceed 400mg, the same as a healthy adult. An 8-ounce cup of brewed coffee contains about 135mg of caffeine; an 8-ounce Red Bull has about 76mg.

Because children weigh less than adults, they’re more susceptible to the chemical’s effects, says child psychiatrist Elizabeth Burger, a spokes-person for the American Academy for Child and Adolescent Psychiatry. As with adults, caffeine can keep young children up at night and contribute to higher blood pressure, a racing heart rate and a grouchy or overly excited mood. During the summer, caffeine can quickly make your child dehydrated.

Make sure caffeinated beverages don’t replace more nutritious drinks, such as milk and water. “Kids become mildly addicted to soft drinks, which are empty calories that contribute to obesity,” says Bonnie Liebman, director of nutrition at the Center for Science in the Public Interest. It’s all a matter of balance.