Caffeine is used around the globe, with 90 percent of people worldwide consuming it in some form and 80 percent of Americans using it daily, according to the U.S. Food and Drug Administration. One of caffeine's most obvious biological effects is making you feel awake. Less desirable effects include increased heart rate, dehydration and withdrawal when you go without.
Foods, Drinks and Drugs
Caffeine is found naturally in some plants, but is also added to foods and drugs. Although it's often associated with coffee and tea, caffeine is also found in many other items. An average cup of coffee has 100 to 200 milligrams of caffeine, but some chains offer versions with as much as 435 milligrams. Teas have about 5 to 135 milligrams, while soft drinks can have up to about 70 milligrams per 12 ounces. Energy drinks range from about 50 to 280 milligrams.
Caffeine is a stimulant, which explains its ability to save the day for the otherwise exhausted. But it also changes how your body and brain work. Too much can make you thirsty, jittery or dizzy. Caffeine also increases the release of stomach acid, causing heartburn in some people. It can be addictive, causing irresistible cravings and difficult withdrawal symptoms including headaches, muscle aches, irritability and depression. Caffeine also causes the heart to contract at a faster and more forceful rate.
Is Any Caffeine OK?
Average American adults ingest about 200 milligrams of caffeine per day, equal to about two 5-ounce cups of coffee or four sodas. The FDA notes drinking 600 milligrams or more is too much; however, smaller amounts -- around 100 to 200 milligrams -- are probably OK. Tolerable amounts also depend on someone's weight, age and sensitivity to caffeine. The use of caffeine in pregnant women is controversial; however, generally 100 to 200 milligrams a day is considered safe. MotherToBaby, a service of the Organization of Teratology Information Specialists, notes caffeine crosses the placenta, potentially affecting a fetus.
How to Cut Down
Going cold turkey can cause withdrawal symptoms, so cut down gradually if you're trying to reduce caffeine intake. Try drinking more tea and less coffee, as tea provides smaller amounts of caffeine. Eating breakfast keeps energy levels steady, and regular exercise can combat fatigue, notes the American Council on Exercise.