Health and Wellness: Caffeine

April 11, 2008

Caffeine is a naturally occurring substance found most commonly in things like coffee, cocoa beans, kola nuts and tea leaves. Caffeine levels in food products differ according to preparation methods, serving sizes and source. An eight-ounce cup of drip-brewed coffee, for example, contains 65 to 125 mg of caffeine, while an eight-ounce serving of brewed tea contains 20 to 90 mg. A 12-ounce can of soda contains 30 to 60 mg of caffeine.

Consumption of caffeine per capita for all consumers is about 120 mg/day. Children consume significantly less caffeine than adults (between 14 and 22 mg/day), with their primary source coming from soft drinks and tea. Adults consume most of their caffeine from coffee. Another growing source of caffeine for all ages is the ever-popular energy drink, which can contain between 50 and 160 mg of caffeine (or more) per eight-ounce serving.

Caffeine acts as a mild stimulant on the central nervous system, enhancing self-rated moods like efficiency, vigor, energy and clear-headedness. Recent studies even demonstrate a connection between caffeine consumption and increases in cognitive function, especially as it is related to alertness. Additionally, caffeine consumption has been shown to improve physical performance and endurance.

But caffeine sensitivity fluctuates greatly from person to person, and can vary according to an individual's frequency of consumption, their metabolism, their genetics, and other natural factors. Certain sensitive sub-populations, including pregnant women, children and older individuals, and those with a history of heart disease, may experience the effects of caffeine at lower levels, and should limit their consumption to no more than 300 mg/day.

Even with these considerations, The American Psychiatric Association cites no evidence for caffeine withdrawl or anxiety. Researchers have also found little association between coffee consumption and the risk of coronary heart disease, stroke or hypertension in healthy populations.

In terms of caffeine myths and misperceptions, especially pertaining to things like dehydration, osteoporosis, heart disease, and heartburn, research has found that caffeine does not cause any of these conditions. Similarly, several studies examining the relationship between caffeine and reproductive health found that moderate intake of caffeine does not cause birth defects, miscarriage, premature birth, delayed conception or low birth weight.

Although epidemiological data on the effects of caffeine during pregnancy are conflicting (as many of the studies test for the effects of both caffeine and smoking simultaneously, among other factors), women who are pregnant or are planning to become pregnant, or who are breastfeeding, can safely consume caffeine but should limit their consumption to no more than three cups a day. This same rule applies to other higher-risk populations.

For healthy adults, caffeine consumption of 300 mg/day is considered safe, and even beneficial. Some studies actually show a reduction in insulin sensitivity from both caffeinated and decaffeinated coffee. Others point to a reduced risk of Parkinson’s Disease, a protective effect against colon and colorectal cancers, a reduction in the risk of developing chronic liver disease, and improved immune function. For more information about caffeine, and coffee in general, sign up for our free monthly e-newsletter Coffee Chat News.

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