What is caffeine?


Caffeine is a stimulant. According to the National Institutes of Health, caffeine is a chemical compound found in various plants that acts as a central nervous system stimulant. Caffeine is found mainly in coffee, tea, soda, chocolate, energy drinks and some over-the-counter medications. As of now, the Food and Drug Administration doesn’t have specific recommendations for caffeine intake, although they are beginning to investigate caffeine being added to products.  It's recommended that adult consumption be between 300-400 mg (that's equivalent to 3-4 cups of coffee) and teens be around 100 mg.

William B. Salt II., MD
Caffeine is a strong stimulant found in coffee, tea, chocolate, soft drinks and many over-the-counter medications and prescription drugs. It affects the brain, heart and gastrointestinal (GI) system. Caffeine enhances the pain-relieving effects of aspirin or acetaminophen and for this reason it is added to some prescription headache medications. When combined with caffeine, the same amount of relief from pain is obtained using 40% less of the analgesic drug.
Irritable Bowel Syndrome & the Mind-Body Brain-Gut Connection: 8 Steps for Living a Healthy Life with a Functiona (The Mind-Body Connection Series)

More About this Book

Irritable Bowel Syndrome & the Mind-Body Brain-Gut Connection: 8 Steps for Living a Healthy Life with a Functiona (The Mind-Body Connection Series)

One in five people suffer from irritable bowel syndrome, colitis, or other functional bowel disorders. As a result, irritable bowel syndrome is the second leading cause of worker absenteeism. This...
Caffeine is a substance found in the leaves and beans of the coffee tree, in tea, yerba mate, guarana berries, and in small amounts in cocoa. It can also be made in the laboratory, and is added to some soft drinks, foods, and medicines. Caffeine increases brain activity, alertness, attention, and energy. It may also increase blood pressure, heart rate, breathing rate, and the loss of water from the body in urine.

This answer is based on source information from the National Cancer Institute.
Caffeine is a central nervous system stimulant that has the effect of increasing alertness and decreasing drowsiness. It is most often consumed by humans as an infusion that is extracted from either the tealeaf or the coffee bean. Caffeine is considered to be the world’s most widely used psychoactive substance and there are now estimates that over ninety percent of adults in North America consume caffeine.  Caffeine is absorbed in the stomach and small intestine within forty-five minutes of ingestion and distributed throughout the body. The half-life of caffeine (how long it stays in your body.  is fully absorbed and no longer has any effect) is generally five hours but can be up to ten hours in women taking oral contraceptives, and nine to eleven hours in pregnant women.
About 90 percent of Americans take in some form of caffeine every single day. More than half of all American adults consume 300 milligrams (mg) or more of caffeine every day. It is America's most popular drug by far.

Caffeine is naturally found in chocolate, coffee and tea, and is added to most colas and energy drinks. Diet pills and some over-the-counter pain relievers also can contain caffeine. Medically, caffeine is known as trimethylxanthine. When isolated in pure form, caffeine looks like a white crystalline powder and tastes very bitter. Pure caffeine is usually harvested through the process of decaffeinating coffee and tea.

Medically, caffeine can be used as a cardiac stimulant or as a mild diuretic -- it increases urine production.
Recreationally, caffeine is used to provide a boost of energy. People who use caffeine can gain a feeling of heightened alertness. Typically, college students use it to stay awake while cramming for finals. Drivers use it to push through to their destination. Some regular users feel as though they cannot function in the morning without coffee to provide caffeine.

Caffeine is an addictive drug. That's important to know. It operates with the same mechanisms that amphetamines, heroin and cocaine use to stimulate the brain. Relatively speaking, caffeine's effects are not as strong as amphetamines, heroin and cocaine, but it does manipulate the same channels in the brain. That is one reason it is addictive.

Continue Learning about Coffee & Health

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.