The Effects of Caffeine Works Cited Not Included Caffeine has played a central role in many cultures. Coffee was first discovered more than 1,000 years ago, and approximately 75% of Americans drink coffee regularly. Despite the passing of a thousand years, there is still controversy over the biological effects of coffee and its primary active ingredient, caffeine. Caffeine is the most widely used stimulant drug in the world, usually ingested in the form of coffee, tea, soft drinks and chocolate. (Honig) Caffeine comes from a bean or tea leaf and can be found in the seeds or fruits of more than 60 species worldwide. (American Academy) Caffeine has numerous effects, and it is controversial whether caffeine is overall beneficial or harmful. Caffeine is a naturally occurring xanthine substance (precursor of uric acid often present in urine) used as a stimulant of the central nervous system (CNS) and respiratory system or as a mild diuretic. Other xanthine derivatives include the bronchodilator theophylline and theobromine, a compound found in cocoa and chocolate. Caffeine is a mild but direct stimulant at all levels of the central nervous system that also speeds up the heart and cardiovascular system. The related xanthine, theophylline, shares these characteristics and is used in the treatment of lung diseases. Both caffeine and theophylline are central nervous system stimulants, with theophylline exerting more dramatic effects than caffeine at higher concentrations. Caffeine also stimulates the medullary respiratory center and relaxes the bronchial smooth muscles. Caffeine stimulates… half of the article… defects, asthma, fibromyalgia, chronic fatigue, autoimmune diseases and rheumatoid arthritis. (James) Many studies have suggested a relationship between chronic caffeine consumption and a number of diseases. However, cause-and-effect evidence is difficult to demonstrate due to variables related to the lifestyle of the subjects involved in the studies (e.g. smoking, alcohol consumption, physical exercise), differences in genetic inheritance, the of caffeine intake (coffee, tea, soft drinks) and the presence of other biologically active substances in the drink. (Brice) Caffeine consumption has side effects, some negative and some positive, but it is clear that if taken in moderation caffeine is never harmful to your health. However, caffeine consumers should be aware of withdrawal and keep up to date on the latest caffeine research.