Caffeine: A Surprisingly Common Substance

According to Wikipedia, the chemical substance called caffeine was first discovered by a German chemist named Friedrich Ferdinand Runge in 1819. When distilled, caffeine (or as it was originally called in German: kaffein)is a bitter white crystalline substance that is found in such plants as guarana (a climbing plant in the maple family), yerba mate (another plant that grows in South America), cacao and tea, not to mention the coffee tree.

Caffeine is found in varying quantities in the beans, leaves and fruit of certain plants, where it acts as a natural pesticide that paralyzes and kills certain insects that feed on the plants. Caffeine is most commonly consumed by humans in infusions extracted from the cherries of the coffee plant and the leaves of the tea bush, as well as from various foods and drinks containing products derived from the kola nut. Other sources include yerba mate, guarana berries and the Yaupon Holly.

In humans, caffeine is a central nervous system stimulant, and has the effect of temporarily warding off drowsiness and restoring alertness. According to Wikipedia, caffeine is also one of the world's most widely consumed psychoactive substances, but unlike many other psychoactive substances it is legally produced and unregulated in virtually all jurisdictions.

In North America, caffeine is consumed daily by 90 per cent of all adults. The U.S. Food and Drug Administration lists caffeine as a "Multiple Purpose Generally Recognized as Safe Food Substance." Caffeine has diuretic properties, at least when administered in sufficient doses to people who do not have a tolerance for it. Regular users however develop a strong tolerance to this effect, and studies have generally failed to support the popular idea that the consumption of caffeinated beverages contributes to dehydration.