There is a lot of debate around whether caffeine is “safe” or not. There are old wives’ tales regarding coffee stunting children’s growth and leeching calcium from bones. But does it? Caffeine is often used as a stimulant to help users stay mentally and physically alert. What sorts of benefits does it really give? Nearly all of us have felt our hearts race after an energy drink or an extra strong cup of coffee. Could caffeine be to blame for heart disease and high blood pressure? Does it cause cancer? Is it addictive and can you experience withdrawal? Some tout it as a cure for hyper activity and/or ADHD. Since it crosses the blood-brain barrier how much is “safe” for adults? Could it be a leading cause of infertility? What are its effects after crossing the placental barrier? Is it “safe” for children? Is caffeine really “good” or “bad”? For such a ubiquitous substance I feel I have a severe lack of knowledge on the subject. With the following posts I hope to educate myself and readers on one of my favourite substances. By discussing findings in the literature hopefully some of the questions asked above can be answered.
So where does dietary caffeine come from? Caffeine (1,3,7-trimethylxanthine) is a nitrogenous organic compound produced by plants. It is found in the seeds, fruit and leaves of plants such as coffee (beans), cocoa (beans), tea (leaves), and kola (nut). When these plants are ingested we inevitably intake some caffeine. Caffeine compounds are also added to consumables such as soft drinks, chocolate, energy drinks, and medications (cold, headache and pain remedies, over the counter stimulants and other drug products)1,2. According to Health Canada Canadian adults get approximately 60%, 30% and 10% of their caffeine from coffee, tea and cola beverages/chocolate/medicines respectively. Children (1-5yrs) get approximately 55%, 30% and 14% from cola drinks, tea and chocolate respectively.
Health Canada1 recommends healthy adults keep caffeine intake to 400 mg/d (about 3 8oz cups of brewed coffee), 300 mg/d for women of childbearing age and 2.5mg/kg for children. That is approximately 45mg for children 4-6 years old, 62.5mg for children 7-9 and 85 mg for children 10-12. These ranges encompass about 1-2 12oz cans of cola per day (considering the health effects of caffeine only). To accurately calculate your daily caffeine intake visit Health Canada’s website where they provide a detailed guide on amounts of caffeine found in various foods.
For some additional information on caffeine consumption visit these websites (accessed September 2013).
Graphs on international coffee consumption
Interesting graphs on Canadian beverage consumption – soft drink industry website
1 Nawrot P, Jordan S, Eastwood J, Rotstein J, Hugenholtz A & Feeley M (2003) Effects of caffeine on human health. Toxicological Evaluation Section, Chemical Health Hazard Assessment Division, Bureau of Chemical Safety, Food Directorate, Health Canada. Food Additive and Contaminants 20,1-30.
2 Health Canada (2013) Caffeine: It’s your health. http://www.hc-sc.gc.ca/hl-vs/iyh-vsv/food-aliment/caffeine-eng.php (accessed September 2013).