The Food Journal and Food, Nutrition & Science

An alliance between The Lempert Report and The Center for Food Integrity



Health and Wellness

April 27, 2008

Caffeine consumption of 300 mg/day or less does not cause adverse effects, according to an International Food Information Council (IFIC) review of recent key research on caffeine and health. The review looks at caffeine’s effects on a variety of health conditions, as well as health benefits, and refutes some common misperceptions about caffeine.
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.
“Research on caffeine and fatigue has found that caffeine inhibits the production of adenosine. This inhibition increases dopamine levels in the brain, which can allow for longer periods of exercise and increased performance,” says Lindsey Monroe, Director, Food Ingredient Communications for IFIC.
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 consult a physician about their caffeine intake.
“Another factor contributing to caffeine sensitivity is frequency of caffeine consumption. Regular caffeine consumers are less sensitive to its effects,” says Monroe.
Even with these considerations, researchers have found little association between coffee consumption and the risk of coronary heart disease, stroke or hypertension in healthy populations. And, the American Psychiatric Association cites no evidence for true caffeine withdrawal or anxiety.
“Behaviors associated with removal of caffeine from the diet in no way resemble the behavior of a person going through true withdrawal to addictive stimulants,” says Monroe. “Headaches can largely be prevented through gradually reducing caffeine consumption over time, instead of discontinuing consumption all at once. Symptoms from stopping caffeine entirely are generally short-lived and mild in nature.”
In terms of caffeine myths and misperceptions, especially pertaining to things like dehydration, osteoporosis, heart disease, and heartburn, the IFIC review 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 birthweight.
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 planning to become pregnant, or who are breastfeeding, can safely consume caffeine but should limit their consumption to no more than three cups of coffee a day. This same rule applies to other higher-risk populations.
For healthy adults, caffeine consumption of 300 mg/day is considered safe, and can even have some benefits. 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.
“Some of the newest research in mice has shown a relationship between elevated levels of adenosine-blocking caffeine and protection from the animal version of Multiple Sclerosis,” adds Monroe. “The findings of this recent study, presented at the 2008 Experimental Biology Conference in San Diego, raise hope that adenosine-based treatment of MS may exist in the future; however, the research is still in its exploratory phase at this time.”