What is caffeine?
Caffeine is a food component naturally present in coffee beans, tea leaves including yerba mate, cocoa beans, and guarana berries, but it can also be made in the lab and added to foods, drinks and medicines. Caffeine is a stimulant that boosts alertness, energy and brain activity. Daily caffeine intake and primary sources vary by country and dietary habits, but coffee and tea are the two most prominent sources.
What are the effects of caffeine on children?
In Japan, there are no age restrictions on caffeine consumption; however, the Ministry of Health, Labour and Welfare explains that children’s bodies and brains are more susceptible to the effects of caffeine than adults, and caution is needed regarding children’s caffeine intake. Caffeine can remain in the body for over eight hours. When its effects wear off, individuals may experience headaches, irritability, or feelings of fatigue. Caffeine also increases the excretion of calcium, which is vital for bone growth. Furthermore, excessive caffeine intake can overstimulate the central nervous system, potentially causing the following side effects:
- Fast or irregular heartbeat
- Elevated blood pressure
- Rapid breathing
- Dizziness
- Anxiety
- Nausea
- Vomiting
- Restlessness
- Diarrhea
- Sleep deprivation, insomnia
Caffeine content in foods:
| Source | Caffeine concentration |
|---|---|
| Coffee | 60 mg/100 ml |
| Instant coffee powder | 57 mg/100 ml |
| Black tea | 30 mg/100 ml |
| Green tea | 20 mg/100 ml |
| Energy drinks* | 32–300 mg/100 ml |
- *The caffeine concentration and net quantity vary depending on the product.
Health Canada's maximum caffeine intake without adverse effects:
| Children aged 4 to 6 | No more than 45 mg per day |
|---|---|
| Children aged 7 to 9 | No more than 62.5 mg per day |
| Children aged 10 to 12 | No more than 85 mg per day |
| Adolescents 13 and older | No more than 2.5 mg/kg body weight (e.g. weight 40 kg=100 mg/day) |
It is important to check the caffeine content listed on product labels and ingredient lists. Particular caution is needed with energy drinks, as they contain both sugar and high concentrations of caffeine; a single canned drink can easily exceed the recommended daily limit. At KIST, we prioritise children’s health and safety and do not sell drinks containing high levels of caffeine, such as coffee or energy drinks, to children at K. Shop or from the vending machines.
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