Drinking coffee is legal, even socially encouraged. Many people believe it is a nondrug item, it is not really addictive, and it tastes good. Besides, with no cream and sugar added, it is calorie-free and therefore a good way to fill up a dieting stomach. Those of us sharing these attitudes may need some reeducation before making choices concerning our consumption of products containing caffeine.

         What exactly is caffeine? Whether we choose to admit it or not, caffeine is a drug, derived from the chemical family called xanthines. Two related chemicals, theophylline and theobromine, are found in tea and chocolate, respectively.
         Caffeine and related substances are hidden in many foods and over-the-counter (OTC) medications. The consumer wishing to eliminate or reduce caffeine intake may be surprised to find caffeine in many soft drinks, chocolate bars, some brands of corn chips, OTC stimulants, diuretics, diet aids, analgesics, and antihistamines.
         The xanthines are stimulants. They enhance mental alertness and reduce fatigue. Other stimulant effects include increased heart muscle contractions, increased oxygen consumption, increased metabolism of some nutrients, and increased urinary output.
         Some research has shown that caffeine increases both our ability to learn and the speed and accuracy of several intellectual processes. Typing speed may also increase, and driving skills may be enhanced. Other studies contradict these findings and show impaired performance in motor skills requiring fine muscle control and timing.
         As with other drugs, the psychological outlook and the expectations of the user will greatly affect the stimulant effects of xanthine-containing products. An 8-ounce cup of coffee or tea contains 100 to 150 milligrams of caffeine. Caffeine concentrations vary with the brand of beverage and strength of the brew. Small chocolate bars contain up to 15 milligrams of caffeine and theobromine. Colas and other caffeinated soft drinks contain between 35 and 65 milligrams per 12-ounce can. An 8-ounce cup of hot chocolate contains 50 milligrams of caffeine and theobromine.
         Stimulant effects of xanthines occur within 30 minutes of consumption. Side effects also begin to occur within this time period. Side effects, which in the case of xanthines are extensions of the main effects, include wakefulness, insomnia, psychomotor irritability, occasional heart arrhythmias (irregular heartbeat), dizziness, nausea, indigestion, and occasionally mild delirium. Although most people would have to drink more than five cups of coffee to experience these symptoms, some people will feel them after only one cup. Unless additional caffeine is ingested, the effects last from 50 to 75 minutes. At doses greater than 400 milligrams (three or more cups of coffee), users may become extremely irritable and nervous and may experience tremors and headache.

Caffeinism 
         As the effects of caffeine begin to wear off, the user may feel let down, mentally or physically depressed, exhausted, and weak. To counteract these effects, a person will most probably drink another cup of coffee. Engaging in such practices habitually will lead to tolerance and psychological dependency.
         Until the mid-1970s, caffeine was not medically recognized as addictive. Chronic caffeine use and its attendant behaviors were called "coffee nerves." This syndrome is now recognized as caffeine intoxication, or caffeinism. Symptoms of caffeinism include chronic insomnia, jitters, irritability, nervousness, anxiety, and involuntary muscle twitches. Withdrawing the caffeine may compound the effects and produce severe headaches. (Some physicians ask their patients to take a simple "test" for caffeine addiction: Don't drink or consume anything containing caffeine, and if you get a severe headache within 4 hours, you are addicted.) Because cafteinism meets the requirements for addiction tolerance, psychological dependence, and withdrawal symptoms it can be classified as addictive. Caffeine is a bigger problem than we may realize. Researchers estimate that approximately 6 percent of Americans suffer from caffeinism and another 15 percent of Americans are considered to be undiagnosed caffeine addicts.
         Although a person would have to drink between 67 and 100 cups of coffee in a day to produce a fatal overdose, sensory disturbances may be felt after consuming 10 cups of coffee within a 24-hour period. These include tinnitus (ringing in the ears), spots before the eyes, numbness in arms and legs, poor circulation, and visual hallucinations. Because 10 cups of coffee is not an extraordinary amount for many people to drink within a 24-hour period, caffeine use clearly poses health threats.

Medical Problems and Long-Term Caffeine Use
         Many medical researchers claim that long-term caffeine consumption contributes to heart disease, cancer, gastrointestinal problems, kidney disturbances, genetic damage to unborn children, mental dysfunction, low blood sugar (hypoglycemia), and hyperactivity. Research supporting or refuting these claims is not yet conclusive, but the evidence suggests that caffeine use is a contributing factor in many of these ailments.
         A study released in November 1985 indicated that drinking five or more cups of coffee per day might contribute to heart disease. Other research has shown an increase in the rate of heart attacks among coffee drinkers as opposed to abstainers. However, it is not known whether the caffeine or some other factor influences this trend.
         Teratogenic effects are those that cause abnormal fetal development resulting in birth defects. Such effects have been demonstrated in laboratory animals that were subjected to extreme doses of caffeine. Because of the difficulty in applying animal study results to human disease processes, the teratogenic effects of caffeine upon a developing human fetus are unknown. Any drug ingested during pregnancy, particularly during the first three months, may be hazardous to the fetus, so abstention is recommended.
         Caffeine consumption has also been linked with fibrocystic breast disease, a disorder characterized by the growth of noncancerous lumps in female breast tissue. Whether or not caffeine consumption or fibrocystic breast disease is related to the later development of breast cancer in women is unknown.