Caffeine is present in coffee, tea and colas as well in many diet preparations including Hydroxycut, Dexatrim and some Nutrisystem products. Caffeine remains the principal ingredient of most energy drinks and may be purchased in tablet form as NoDoz or Vivarin. Caffeine is even present in Excedrin and other pain relievers.
More than 80% of adults consume caffeine on a daily basis with domestic intake ranking well behind that of Norway, Finland and the United Kingdom. Americans average approximately 200 mg daily with suggested upper limits of 400 mg for healthy adults and 200 mg for pregnant women with much smaller amounts for children and adolescents.
Coffee contains more than 1000 different chemicals including some that provide antioxidant, anti-inflammatory and anti-cancer activities. Surveying the risks and benefits, it seems coffee offers significant potential for improving health.
Caffeine improves alertness, mood and focus. It assists in memory consolidation, decreases drowsiness, aids in coordination and reduces mistakes among shift workers. Studies demonstrate coffee may reduce the rate of cognitive decline in seniors and lower the rate of stroke, heart disease, diabetes, cirrhosis and Parkinson’s Disease. Caffeine appears to reduce the incidence of cancers of the prostate, colon, liver and uterus.
Additional benefits include protection against kidney stones and cataracts. Caffeine improves the overall sense of well being and lowers the likelihood of premature death.
Some experience toxicity including headache, nausea, loss of appetite, restlessness and excessive gastrointestinal motility. Caffeine may induce jitteriness, disturb sleep and lead to anxiety or panic attacks. It rarely leads to elevated blood pressure of cardiac arrhythmias but may predispose to bone loss in susceptible individuals.
Sensitivity to side effects depends on genetic factors involving liver metabolizing enzymes and variations in the genes responsible for the adenosine receptor - the target of caffeine. A typical cup of coffee contains 50-200 mg of caffeine with energy drinks and some Starbucks fare ranging between 200-400 mg. Substantial toxicity develops with more than 1000 mg and fatalities are expected with 10,000 mg or just one tablespoon on powdered product.