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).
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.
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.
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.
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.
You may want to limit your caffeine intake if:
Watch how much caffeine a child gets. Caffeine is a stimulant and a hyperactive child may need to avoid it. Small amounts of caffeine during pregnancy are safe. Avoid large amounts.
Many drugs will interact with caffeine. Talk to your health care provider about possible interactions with the medicines you take.
If you are trying to cut back on caffeine, reduce your intake slowly to prevent withdrawal symptoms.
Reviewed By: Emily Wax, RD, The Brooklyn Hospital Center, Brooklyn, NY. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.