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Caffeine in the diet

Diet - caffeine

Caffeine is a substance that is found in certain plants. It can also be man-made and added to foods. It is a central nervous system stimulant and a diuretic (substance that helps rid your body of fluids).

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Function

Caffeine is absorbed and passes quickly into the brain. It does not collect in the bloodstream or get stored in the body. It leaves the body in the urine many hours after it has been consumed.

There is no nutritional need for caffeine. It can be avoided in the diet.

Caffeine stimulates, or excites, the brain and nervous system. It will not reduce the effects of alcohol, although many people still erroneously believe a cup of coffee will help a person "sober-up."

Caffeine may be used for the short-term relief of fatigue or drowsiness.

Food Sources

Caffeine is widely consumed. It is found naturally in the leaves, seeds, and fruits of more than 60 plants, including:

It is also found in processed foods:

Caffeine is often added to over-the-counter medicines such as pain relievers, over-the-counter diet pills, and cold medicines. Caffeine has no flavor. It can be removed from a food by a chemical process called decaffeination.

Side Effects

Caffeine can lead to:

Stopping caffeine suddenly may cause withdrawal symptoms. These may include:

There has been much research on the health effects of caffeine.

Caffeine may harm a child's nutrition if drinks with caffeine replace healthy drinks such as milk. Caffeine cuts down on appetite so a child who consumes caffeine may eat less. The United States has not developed guidelines for caffeine intake by children.

Recommendations

The American Medical Association Council on Scientific Affairs states that moderate tea or coffee drinking is not likely to be harmful to your health as long as you have other good health habits.

Four 8 oz. cups (1 liter) of brewed or drip coffee (about 400 mg of caffeine) or 5 servings of caffeinated soft drinks or tea (about 165 to 235 mg of caffeine) per day is an average or moderate amount of caffeine for most people. Consuming very large amounts of caffeine (over 1200 mg) within a short time period may lead to toxic effects such as seizures.

You may want to limit your caffeine intake if:

Watch how much caffeine a child gets.

Small amounts of caffeine during pregnancy are safe. Avoid large amounts.

If you are trying to cut back on caffeine, reduce your intake slowly to prevent withdrawal symptoms.

Related Information

Central nervous system
Migraine
Fatigue
Drowsiness

References

Coeytaux RR, Mann JD. Headache. In: Rakel D, ed. Integrative Medicine. 4th ed. Philadelphia, PA: Elsevier; 2018:chap 12.

Committee on Nutrition and the Council on Sports Medicine and Fitness. Sports drinks and energy drinks for children and adolescents: are they appropriate? Pediatrics. 2011;127(6):1182-1189. PMID: 21624882 pubmed.ncbi.nlm.nih.gov/21624882/.

U.S. Food & Drug Administration. Spilling the beans: how much caffeine is too much? www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much? Updated December 12, 2018. Accessed August 12, 2021.

Bakris GL, Sorrentino MJ. Systemic hypertension: mechanisms and diagnosis. In: Zipes DP, Libby P, Bonow RO, Mann DL, Tomaselli GF, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 12th ed. Philadelphia, PA: Elsevier; 2022:chap 26.

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Review Date: 6/8/2021  

Reviewed By: Meagan Bridges, RD, University of Virginia Health System, Charlottesville, VA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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