Could Mikey's chocolate breakfast cereal make him jittery? What about the carbonated lemonade he had at summer camp? It may surprise some parents to find out that caffeine is in many of the foods and beverages their kids consume!

Which Foods Contain Caffeine?

Methylxanthines are a group of compounds that are abundant in foods and beverages popular with kids and teens. The methylxathine group includes theobromine and caffeine. The obvious and most common source of caffeine is soft drinks. According to the American Beverage Association, "one of every four beverages consumed in America today is a soft drink, averaging out to over 56 gallons of soft drinks per year for every man, woman, and child."

A study in the Canadian Journal of Dietetic Practice and Research found that 56% of American children and 36% of Canadian children consume caffeinated beverages. According to another study, 55% of the caffeine consumed by children aged 3-5 years old is from carbonated beverages, while 38% is from cocoa and chocolate products. Other food sources of methylxanthine are bottled iced teas, chocolate desserts, chocolate flavored breakfast cereals, and over-the-counter medications.

Other beverages that have been growing in popularity among teenagers include energy drinks such as Red Bull and Amp, and specialty coffees, all loaded with caffeine. According to a study in the Nutrition Journal , most energy drinks contain 80-141 milligrams (mg) of caffeine per eight ounces—that’s the same as just five ounces of coffee or two cans of Coca Cola.

Little information is available about the theobromine content of foods, but major sources include cocoa and chocolate products. In a research study of caffeine and theobromine content in 12 chocolate cereals, researchers found that chocolate cereals were not a significant source of caffeine, but were a major source of theobromine, in comparison to carbonated beverages, coffee, and tea. Theobromine is a much milder stimulant than caffeine, but is a stronger diuretic.

Methylxanthines Can Get on Your Nerves

Methylxanthines are categorized as central nervous system stimulants. These compounds can affect brain blood flow, metabolism, and breathing, as well as kidney and gastrointestinal function.

In moderate doses, caffeine increases alertness, reduces fine motor coordination, increases the time to fall asleep, and may cause headaches, nervousness, and dizziness.

Within 45 minutes, about 99% of caffeine is absorbed. It takes about six hours for 50% of the caffeine to be eliminated from the system.

How Much Is Too Much?

Unfortunately, there is no consensus in the medical community about upper limits of caffeine intake for kids and teens. For adults, moderate caffeine consumption is estimated to be about 350 mg or less per day, the amount found in about 15 ounces of brewed coffee. Some studies have described a "high" caffeine intake in children as being greater than 3 mg/kg (milligrams per kilogram) of body weight. For a 65-pound child, this translates to about 90 mg of caffeine.

Caffeine and Health

Ellyn Satter, a dietitian and author of Child of Mine: Feeding with Love and Good Sense , warns that caffeinated beverages not only work as unwanted stimulants, but they replace more healthful drinks, such as milk.

Many nutritionists echo Satter's concerns. In fact, most studies indicate that many children and teens do not meet the recommended intakes for calcium. And if kids are drinking high-caffeine, high-sugar drinks too often, they may not be hungry for more nutritious foods.

But some scientific studies on the effects of caffeine intake in young people say that modest caffeine intake does not have negative consequences. The Penn State Young Women's Health Study found that dietary caffeine intake at levels consumed by white American teenage women is not correlated with total bone mineral gain or hip density at age 18. The researchers did note, however, that women who consumed less caffeine consumed greater amounts of milk and fruits.

Other studies have looked at the effects of caffeine on school performance. Low doses of caffeine may have actually enhanced performance, attentiveness, and some motor tasks, although the children also reported increased anxiety .

Caffeine Labeling

Michael F. Jacobson, PhD, of the public advocacy organization Center for Science in the Public Interest (CSPI), says that his organization has crusaded for better caffeine content labeling because of perceived health concerns about caffeine, and because there is such variability in caffeine content from brand to brand. He notes that while a cup of regular coffee-flavored yogurt may have has much caffeine as a 12-ounce can of cola, another version of cappuccino yogurt made by the same company may have no caffeine.

Current labeling laws require that when caffeine is added to a food or beverage, its presence must be indicated on the list of ingredients, but how much caffeine is added does not have to be listed. The US Food and Drug Administration (FDA) limits the added caffeine in beverage products to 6 mg per ounce (for example, 72 mg per 12-ounce canned beverage).

What Can Parents Do?

Because of labeling laws, it can be hard for parents to know how much caffeine their kids are consuming. One tip is to purchase only those beverages labeled "caffeine-free." With food items other than beverages, the only accurate method of determining the caffeine content of foods and beverages is to contact the food manufacturer.

Until food labels note the caffeine and theobromine content of foods, parents can take the following steps:

  • Be aware that some chocolate cereals contain theobromine, which can have a diuretic effect, especially in young children who consume large servings.
  • Purchase beverages labeled "caffeine-free".
  • Limit overall intake of soda from restaurants.
  • Encourage children and teens to choose water over soda, energy drinks, or coffee drinks.
  • Be aware of over-the-counter medications that contain caffeine (such as some appetite suppressants and headache remedies).