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Caffeine is known medically as trimethylxanthine. When isolated in pure form, caffeine is a white crystalline powder that tastes very bitter. The chief source of pure caffeine is the process of decaffeinating coffee and tea.
Caffeine is a substance that exists naturally in certain plants. It can also be produced synthetically and used as an additive in food products. It is a central nervous system stimulant and a diuretic. Recreationally, it is used to provide a "boost of energy" or a feeling of heightened alertness. It's often used to stay awake longer -- college students and drivers use it to stay awake late into the night. Many people feel as though they "cannot function" in the morning without a cup of coffee to provide caffeine and the boost it gives them.
Caffeine is absorbed and distributed very quickly. After absorption, it passes into the brain. "Caffeine sensitivity" refers to the amount of caffeine that will produce negative side effects. This amount will vary from person to person. Caffeine does not accumulate in the bloodstream nor is it stored in the body. It is excreted in the urine many hours after it has been consumed. Caffeine will not reduce the effects of alcohol, although many people still believe a cup of coffee will "sober up" an intoxicated person.Caffeine may be used as a treatment for migraine headaches and in relieving, for a short time, fatigue or drowsiness.
Excessive caffeine intake can lead to a fast heart rate, diuresis (excessive urination), nausea and vomiting, restlessness, anxiety, depression, tremors, and difficulty sleeping. The effect of caffeine on health has been widely studied. In particular, the effects of caffeine on fibrocystic breast disease, cardiovascular disease, birth defects, reproductive function, and behavior in children has been closely examined and linked to some but not all.
Too much caffeine can cause nervousness and jitters. Like all stimulants, caffeine raises blood pressure and increases the user's risk for high blood pressure, heart disease and other health problems. The amount of caffeine in two to three cups of coffee can raise systolic pressure 3 to 14 millimeters of mercury (mm Hg) and diastolic pressure 4 to 13 mm Hg in people without high blood pressure. Its effects range from mild alertness to heightened anxiety and body tension. In moderate doses it can produce "coffee nerves", throbbing headaches, disorientation, depression and insomnia. Pregnant women, and people with coronary heart disease or peptic ulcers may be advised by their health care provider to restrict or avoid using caffeine. Older women are less able to offset the natural calcium loss that caffeine causes, resulting in increased bone thinning. Moderate your caffeine intake and focus on consuming at least 1,200 mg. of calcium every day. Foods that provide significant amounts of calcium include dairy products, deep-green leafy vegetables and fish with edible bones.
As a precaution, some doctors recommend limiting caffeine to 200 milligrams a day — about the same amount as in two 12-ounce cups of brewed coffee. Keep in mind that the amount of caffeine in coffee and soft drinks varies by brand. Also, avoid caffeine right before activities that naturally increase your blood pressure, such as exercise, weightlifting or hard physical labor, or right before bedtime. That is because the effects of caffeine begin about 15 minutes after you consume it and last up to several hours.
Abrupt withdrawal of caffeine may cause headaches, drowsiness, irritability, nausea, vomiting, and other symptoms. Reduce caffeine intake gradually to prevent any symptoms of withdrawal.
Many medications will interact with caffeine. Consult with your health care provider or pharmacist about potential interactions with caffeine whenever you take medications.
Caffeine is widely consumed. It is found naturally in the leaves, seeds, and fruits of more than 60 plants, including tea leaves, kola nuts, coffee, and cocoa beans. It is in coffee, tea, chocolate, cocoa and many carbonated beverages such as colas.
Caffeine is frequently added to over-the-counter medications such as pain relievers, appetite suppressants, and cold medicines. Caffeine has no flavor and can be removed from a food by a chemical process called decaffeination.
There is no human requirement for caffeine in the diet. Moderate caffeine intake, however, is not associated with any health risk. Three 8 oz. cups of coffee (250 milligrams of caffeine) per day is considered an average or moderate amount of caffeine. Ten 8 oz. cups of coffee per day is considered excessive intake of caffeine. The average American consumes about 230 milligrams (mg) of caffeine a day — about the same amount as in two 12-ounce cups of brewed coffee. For children, the major source of caffeine is carbonated beverages and tea. The average American child consumes about 21 mg of caffeine a day. But this may change as the number and popularity of highly caffeinated, or "supercaffeinated," beverages increases.
Caffeine affects children and adults in the same way. A stimulant, caffeine makes your heart beat faster. It can interfere with sleep and cause nervousness, jitters and irritability. Generally, a caffeinated beverage doesn't satisfy daily water needs because the caffeine will prompt a loss of some or most of the water in the beverage. In addition, research indicates that caffeine makes it difficult for the body to absorb calcium, which children need for strong bones and teeth.
Dehydration is a common side effect of drinking too much caffeine. Although you may think you're getting plenty of liquids, caffeine works against the body in two ways: it has a dehydrating effect on the body's cells and increases the need to urinate. It's particularly important for active teens who play sports to drink non-caffeinated beverages each day to avoid dehydration. Finally, large amounts of caffeine may cause the body to lose calcium and potassium, causing sore muscles and delayed recovery times after exercise .
Caffeine can enter breastmilk, and high amounts can cause the baby to become wakeful and agitated. The American Academy of Pediatrics recommends that nursing women limit caffeine intake, but states that no harm is likely to occur in a nursing child whose mother drinks one cup of coffee a day. Many pediatricians discourage caffeine consumption in kids. This is because children break down caffeine more slowly than adults do and are more susceptible to its effects.
The major sources of caffeine in the diets of children and teens are carbonated beverages and teas. Neither type of beverage provides vitamins and minerals needed for growth and bone development. The combination of acids and sugar in soda pop plays a role in tooth decay. Also, the calorie content of sweetened beverages may contribute to unwanted body weight. Research shows that children often choose soda and tea in place of more healthy selections.
It's probably unrealistic to insist that children be caffeine-free. Instead, parents can offer beverages that contribute to a well-balanced diet. Milk and fruit or vegetable juices can count toward the recommended number of servings from food groups. Water also is an excellent choice. An occasional caffeinated beverage probably won't harm a child. The caffeine content of most of caffeinated sodas and teas is about one-third that of coffee. But parents should steer their children away from the newer supercaffeinated beverages that manufacturers market as equal to or as strong as coffee.
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