Caffeine is probably the most popular legalized drug in the world. The first reports of people enjoying caffeine in the form of tea date back to thousands of years ago in China and in coffee around one thousand years ago in Ethiopia.
The scientific name for caffeine is 1,3,7-trimethylxanthine. Caffeine is naturally found in many plants including tea leaves, coffee and cocoa beans, yerba mate and cola nuts. It was first isolated in 1819 by Friedlieb Ferdinand Runge from coffee beans. It was first synthesized by Emil Fischer in 1895. Caffeine is now also added to several beverages like soft drinks and over the counter medications.
Some people say that caffeine does not affect them while others say that even a small amount of caffeine makes them jittery. The reason that people have different reactions to caffeine may lie in how often they ingest it. Studies show that caffeine has less of an effect in habitual users. People who take caffeine infrequently will feel more alert than people who have it regularly.
Once caffeine is ingested, it reaches maximum blood concentrations about 1-1.5 hours later. Caffeine binds to receptors in the brain. As a stimulant, it makes people more alert and increases heart rate and blood pressure. Caffeine also increases diureses and gastrointestinal motility so that people may feel the need to urinate or pass bowel movements more frequently.
Studies show an association between increased caffeine intake and osteoporosis or weaker bones, but this relationship might be the result of not taking enough calcium in the diet since people may drink soft drinks, coffee, or tea instead of having milk or other dairy products. One study suggests that caffeine may reduce the risk for type 2 diabetes although the amount needed was seven cups of coffee a day.
There are studies that suggest that caffeine may have harmful effects on the growth of a fetus, prompting the recommendation for pregnant women to limit caffeine intake. Children who take caffeine also may have behavioral changes such as more anxiety and insomnia, which may also be seen in adults. People who suddenly stop taking caffeine may have symptoms of withdrawal including headaches, irritability, and drowsiness.
In the U.S., most adults get caffeine from coffee or tea, while children usually ingest it in soft drinks or chocolate. The amount of caffeine in a given beverage or food item depends on the preparation and serving size. Coffee has about 60-120 mg per 8 ounce cup while tea has about 15-45 mg per 8 ounce cup. Keep in mind that when you buy a cup of coffee these days, the smallest size available may be 12 ounces. Soft drinks usually have about 30-50 mg per 12 ounce serving, while Jolt cola is marketed as having extra caffeine and has about 70mg. A 1.5 ounce bar of milk chocolate may have about 10mg of caffeine while the dark chocolate version may have about 30mg. Caffeine pills like NoDoz regular strength have 100 mg per pill.
How much caffeine is acceptable? Adults should try to limit caffeine intake to 200-300 mg per day. Adolescents should have no more than 100 mg per day, and younger children should have even less. If you find you are taking more than 2-3 cups of coffee a day, you may wish to consider switching to decaffeinated coffee. Personally, I will opt for my caffeine fix with a bar of dark chocolate.
Published On: July 27, 2006