Finnish Food Safety Authority Evira has taken part in a project where the exposure of children and adolescents to caffeine in the Nordic countries was assessed. In the risk assessment even small amounts of caffeine were shown to have adverse effects, such as an increase in caffeine tolerance, withdrawal symptoms, anxiety and jitteriness.
Based on the published research, a daily dose of approximately 15 milligram of caffeine does not usually have adverse effects on an adolescent weighing 50 kilo, but the caffeine tolerance can increase with doses exceeding 50 milligram. The increased tolerance is a sign of caffeine addiction, which develops with regular use. Anxiety and jitteriness are observed with daily doses exceeding 125 milligram. Lighter people develop adverse effects from smaller amounts of caffeine. There would also appear to be individual differences when it comes to susceptibility to the adverse effects of caffeine.
One cup of coffee (0.2 litre) contains about 100 milligram of caffeine, one can of energy drink (0.33 litre) about 105 milligram and a bottle of cola drink (0.5 litre) about 65 milligram. With adults using products containing caffeine, even a small amount of caffeine (about 85 milligram of caffeine for a person weighing 60 kilo) can cause sleep disturbance. Caffeine can also cause sleep disturbance in children, but little research has been carried out on the subject. Caffeine stimulates the central nervous system, and therefore impairs sleep onset, reduces the quality of the sleep and reduces sleep time.
Consumption of cola drinks by children and adolescents in the Nordic countries
When reviewing consumption data from all the Nordic countries, the caffeine exposure from cola drinks of about every second child in the age group 4 - 6 years remains below the level causing adverse effects. About ten per cent of the children consuming the most cola drinks, have an intake exceeding the level at which caffeine tolerance can increase.
Even if a minority of adolescents is exposed to caffeine amounts causing anxiety and jitteriness, the consumption level of cola drinks by many adolescents is related to an tolerance development and a risk of withdrawal symptoms. Ten per cent of Icelandic 17-year-olds consumed more than 1.5 litre of cola drinks per day (equivalent to 200 milligram caffeine). In the other Nordic countries, the adolescents consuming most cola drinks (studied 12 - 15 -year-olds) mainly consumed less than 0.5 litre of cola drinks per day (equivalent to 50 milligram caffeine). When the caffeine intake from energy drinks, coffee, tea and chocolate are taken into consideration, the actual exposure is likely to be higher.
Caffeine exposure of Finnish adolescents
Consumption data on drinks containing caffeine consumed by Finnish adolescents was acquired from the Special Turku Coronary Risk Factor Intervention Project (STRIP). The consumption data was collected from 14- and 15-year-old adolescents during 2004 - 2006. About half of the families of the adolescents had received nutritional and life-style counselling from early childhood for the whole duration of the study.
The most important caffeine sources of the adolescents were cola drinks and coffee, of which both contributed about 37 per cent of the daily caffeine exposure. Of the daily caffeine intake of the adolescents, 21 per cent came from tea and 5 per cent from energy drinks. Only 5 per cent of the adolescents consumed coffee and cola drinks in such amounts that could lead to an increase in caffeine tolerance (over 50 mg caffeine). When summing the adolescents’ caffeine intake from coffee, cola and energy drinks, chocolate and other sources, the actual exposure is likely to be considerably higher.
Henrik Rye Lam, National Food Institute, Technical University of Denmark
Marta Axelstad Petersen, National Food Institute, Technical University of Denmark
Kirsi-Helena Liukkonen, Finnish Food Safety Authority (EVIRA)
Elisabeth Jona Solbergsdottir, Department of Pharmacology and Toxicology,
University of Iceland
Helle Margrete Meltzer (project leader), Norwegian Institute of Public Health
Elisabeth Elind (secretary), Norwegian Institute of Public Health
Tor Øystein Fotland (project coordinator), Norwegian Scientific Committee for Food Safety (VKM)
Jan Alexander, Norwegian Institute of Public Health
Helena Hallström, National Food Administration
The project was completed in 2008