Some health effects from caffine

As many people experience, caffeine temporarily relieves fatigue and sharpens mental performance including shortened response time, enhanced memory, and sustained attention. Caffeine has been studied widely because it affects various systems of the body. It affects the cerebral, vasomotor, cardiovascular, digestive, genito-urinary, and immune systems of the body. Often results are equivocal, puzzling, and confusing, due to confounding factors.

In general, there is consensus that moderate intake of caffeine is tolerated by most, but not all; there are exceptions. Habitual high use of caffeine, however, is a risk factor in numerous health disorders.

Caffeine and Health Disorders. Numerous cerebral effects have been attributed to high caffeine intake. According to three research scientists (see sidebar, pg. 14), recent evidence has "confirmed clinical observations that caffeine can induce anxiety, insomnia, intoxication (restlessness, difficulty concentrating, etc.;) and withdrawal (headaches, drowsiness, fatigue, etc.;)." They reported that, in some individuals, anxiety can occur with use of as little as 250 milligrams (mg) of caffeine, and withdrawal, as little as 100 mg a day. (A standard eightounce coffee contains about 85 mg of caffeine.) In susceptible individuals, caffeine can induce true panic attacks that require medical treatment.

High caffeine intake may be linked to seasonal bipolar depression.

The use of over-the-counter medications containing caffeine is associated with sleep problems, especially in the elderly.

Caffeine, as well as alcohol and aspirin, can be toxic to the inner ear. All three substances are associated with tinnitus (ringing in the ear).

Some muscular effects attributed to caffeine include tendinitis, tennis elbow, carpel syndrome, unconscious hand clenching at night or when grasping a car's steering wheel, and significant neck pain rnd headache upon arising in the morning

High levels of tea drinking can produce hypokalemia (a potassium deficiency) manifested by muscle pain, weakness, inability to walk, lift the arms, or raise the head. Theophylline, a closely-related metabolite of caffeine, is one recognized factor in hypokalemia.

Under various conditions, caffeine ingestion has been reported to increase serum cholesterol, blood glucose, and blood pressure, as well as to promote cardiac arrhythmia (irregular heartbeat). In addition, an undesirable increase in platelet reactivity indicts caffeine as an atherogenic substance.

Caffeine is not a major cause of stomach disorders but it does affect the digestive tract. It can cause heartburn,...