MedlinePlus Medical Encyclopedia: Caffeine in the diet

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Caffeine in the diet

Contents of this page:
Alternative names Definition Function	Food Sources Side Effects Recommendations

Alternative names

Diet - caffeine

Definition Return to top

Caffeine is a substance that exists naturally in certain plants. It can also be produced synthetically and used as an additive in food products. It is a central nervous system stimulant and a diuretic.

Function Return to top

Caffeine is absorbed and distributed very quickly. After absorption, it passes into the brain. "Caffeine sensitivity" refers to the amount of caffeine that will produce negative side effects. This amount will vary from person to person.

Caffeine does not accumulate in the bloodstream nor is it stored in the body. It is excreted in the urine many hours after it has been consumed.

Caffeine will not reduce the effects of alcohol, although many people still believe a cup of coffee will "sober up" an intoxicated person.

Caffeine may be used as a treatment for migraine headaches and in relieving, for a short time, fatigue or drowsiness.

Food Sources Return to top

Caffeine is widely consumed. It is found naturally in the leaves, seeds, and fruits of more than 60 plants, including tea leaves, kola nuts, coffee, and cocoa beans. It is in coffee, tea, chocolate, cocoa and many carbonated beverages such as colas.

Caffeine is frequently added to over-the-counter medications such as pain relievers, appetite suppressants, and cold medicines. Caffeine has no flavor and can be removed from a food by a chemical process called decaffeination.

Side Effects Return to top

Excessive caffeine intake can lead to a fast heart rate, diuresis (excessive urination), nausea and vomiting, restlessness, anxiety, depression, tremors, and difficulty sleeping.

The effect of caffeine on health has been widely studied. In particular, the effects of caffeine on fibrocystic breast disease, cardiovascular disease, birth defects, reproductive function, and behavior in children has been closely examined and linked to some but not all.

A 1984 statement from the American Medical Association Council on Scientific Affairs stated "Moderate tea or coffee drinkers probably have no concern for their health relative to their caffeine consumption provided other lifestyle habits (diet, alcohol consumption) are moderate as well." This statement emphasizes moderate caffeine use.

Abrupt withdrawal of caffeine may cause headaches, drowsiness, irritability, nausea, vomiting, and other symptoms. Reduce caffeine intake gradually to prevent any symptoms of withdrawal.

Recommendations Return to top

There is no human requirement for caffeine in the diet. Moderate caffeine intake, however, is not associated with any health risk. Three 8 oz. cups of coffee (250 milligrams of caffeine) per day is considered an average or moderate amount of caffeine. Ten 8 oz. cups of coffee per day is considered excessive intake of caffeine.

A child's caffeine consumption should be closely monitored. Although caffeine is safe to consume in moderation, it may negatively affect a child's nutrition. Caffeinated beverages may be replacing nutrient-dense foods such as milk. A child may also eat less because caffeine acts as an appetite suppressant. Caffeine can be completely restricted in a child's diet since there is no nutritional requirement for it. This may be necessary for a hyperactive child as caffeine is a stimulant.

Pregnant women, and people with coronary heart disease or peptic ulcers may be advised by their health care provider to restrict or avoid using caffeine.

Many medications will interact with caffeine. Consult with your health care provider or pharmacist about potential interactions with caffeine whenever you take medications.

Update Date: 10/17/2003

Updated by: David Webner, M.D., Sports Medicine Fellow, Crozer-Keystone Family Practice Program, Springfield, PA. Review provided by VeriMed Healthcare Network.

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