It's a drug that's readily available to kids at convenience stores, movie theatres, coffee shops and in vending machines. Kids can get a hit from colas, energy drinks, iced cappuccinos, Frappuccinos and chocolate bars. And the larger the serving size, the bigger the hit. These days it's easy for children and teenagers to consume enough caffeine to make them feel jittery, anxious, irritable and sleep deprived.
Consider that a 7-Eleven Big Gulp cola (1.9 litres) delivers 190 milligrams of caffeine -- almost the equivalent of two small cups of coffee. A single-serve bottle (591 ml) of cola -- regular or diet -- delivers as much caffeine as one cup of instant coffee. Most energy drinks contain as much caffeine as two or three cans of cola. Even a king-sized chocolate bar can provide a small child with a strong dose of caffeine.
Caffeine occurs naturally in coffee, tea, cocoa and herbs such as kola nut, guarana and yerba mate. It's also manufactured and used as a food additive in colas, energy drinks, and some cold and headache medications. A growing number of studies suggest that caffeine has the same effects in children and teenagers as it does in adults. At low doses, the stimulating effects of caffeine make you feel more awake, alert and energetic. At higher doses, caffeine can make kids restless, anxious and fidgety, and cause sleep disturbances, headaches and rapid heart rate. At even higher intakes, nausea and stomach upset can occur.
It doesn't take much caffeine to have an effect on a child's mood and behaviour. Research has shown that all it takes is the amount of caffeine found in a single can (355 ml) of cola. Caffeine's effects are based on body weight, so the drug packs a more powerful punch for kids giving them an intensified version of alertness, nervousness and insomnia. While it might take the amount of caffeine in two or three cups of coffee to produce effects in adults, it can take only a fraction of that in kids. And because small children haven't been exposed to caffeine as much as older kids and teens, they are especially sensitive to its effects.
Most kids aren't likely to be aware of how the drug really affects them - the negative effects of too much caffeine, as well as the withdrawal symptoms once their intake goes down. Abruptly stopping caffeine intake can cause fatigue, headaches, muscle soreness, temporary depression and irritability.
In one study of 36 teenagers who consumed caffeine daily, almost 80 per cent reported withdrawal symptoms when they eliminated or reduced their caffeine intake. Another study from the University of Minnesota revealed that when children, ages 6 to 12, stopped consuming caffeine, their attention span and mental performance deteriorated within 24 hours and persisted for one week.
There are other reasons why it's wise to minimize your child's intake of caffeine. Caffeinated beverages like soft drinks and energy drinks often replace healthier ones like milk, soy milk and pure fruit juices. Colas and energy drinks don't provide vitamins and minerals such as calcium, and vitamin D that kids need to build strong bones and teeth.
Consuming too much caffeine could increase a child's future risk of osteoporosis, especially among kids who don't get enough calcium in their diets. Caffeine causes the body to excrete calcium in the urine -- a 355 ml can of cola leaches roughly 20 milligrams of calcium from the body. Research conducted in adults has found that women who consume too much caffeine and not enough calcium are more likely to have lower bone densities compared with women who consume the same amount of caffeine but adequate calcium.
Kids and teens get most of their caffeine from sugary drinks. Too much sugar can lead to weight problems as well as dental caries (cavities).
Experts don't agree on a safe caffeine intake for kids. Some suggest no more than 100 milligrams per day, while others feel 50 milligrams is a more appropriate cut off. In 2003, Health Canada released new caffeine recommendations for children after reviewing scientific research. For kids 12 and under, Health Canada recommends a maximum daily caffeine intake of 2.5 milligrams per kilogram of body weight. For average-weight kids, that means no more than 45 milligrams of caffeine for children aged 4 to 6; 62.5 milligrams for those aged 7 to 9; and at most 85 milligrams daily for 10- to 12-year-olds. These numbers are equivalent to one to two 355 ml cans of cola each day.
You can't tell how much caffeine your child consumes from food and beverages by looking at the label. That's because Health Canada does not require labels to state how much caffeine a product contains. You can get a clue, however, by reading ingredient lists. By law, caffeine has to be listed on labels if it has been added to products as a pure substance (e.g. as caffeine). You'll find it listed on labels of colas and most energy drinks. If caffeine occurs naturally in a food, it's not required to be on the ingredient list. That's why you won't see it on listed on packages of tea, coffee, chocolate bars, chocolate ice cream, chocolate milk and anything mocha or coffee-flavoured.
To get a sense of how much caffeine your child consumes, keep track of foods and beverages containing caffeine consumed over the course of one week, then use the table above to calculate caffeine intake. Leslie Beck, a Toronto-based dietitian at the Medcan Clinic, is on CTV's Canada AM every Wednesday. Visit her website at lesliebeck.com.
The following lists the average caffeine content in milligrams
Coffee, brewed, 227 ml/ 135
Coffee, instant, 227 ml/ 76-106
Coffee, Starbucks, tall 341 ml/ 375
Coffee, espresso, 57 ml/ 70-90
Tea, black, 227 ml/ 43
Tea, green, 227 ml/ 30
Cola, regular, 355 ml/ 36-46
Cola, diet, 355 ml/ 39-50
Mountain Dew Energy, 591 ml/ 90
Red Bull, 250 ml/ 80
SoBe No Fear, 473 ml/ 144
Chocolate milk, 227 ml/ 8
Chocolate cake, 1 slice/ 7
Chocolate ice cream, 250 ml / 6
Chocolate pudding, 250 ml / 18
Milk chocolate, 28 g / 6
Dark chocolate, 28 g / 20
SOURCE: THE MEDCAN CLINIC