Tea - the leaves of Camelia sinensis, is the most widely consumed beverage in the world, second only to water. The Chinese have known about the medicinal properties of green tea since ancient times and used it to treat everything from headache to indigestion and fatigue. Green tea leaves seem to be more beneficial to health than the fermented black tea. The list of conditions and diseases that are believed to be improved or prevented by the consumption of green tea include cancer, rheumatoid arthritis, and cardiovascular disease. Drinking green tea is said to lower blood cholesterol levels and fight infections of the gastrointestinal tract.
An ongoing scientific research in both Asia and the West, is providing evidence for the health benefits long associated with drinking green tea. For example, in 1994 the Journal of the National Cancer Institute published the results of an epidemiological study indicating that drinking green tea reduced the risk of esophageal cancer in Chinese men and women by nearly sixty percent.
A Chinese study of more than 18,000 men, published in 2002, found that green tea drinkers were about half as likely to develop cancer of the stomach or the esophagus than men who drank little or no green tea at all.
University of Purdue researchers recently concluded that a compound in green tea inhibits the growth of cancer cells. There is also research indicating that drinking green tea lowers total cholesterol levels, as well as improving the ratio of good (HDL) cholesterol to bad (LDL) cholesterol.
The secret of green tea lies in the fact it is rich in catechin polyphenols - epigallocatechin gallate (EGCG) in particular. EGCG is a powerful anti-oxidant. It inhibits the growth of cancer cells and kills cancer cells without harming healthy tissue. It has also been effective in lowering LDL cholesterol levels, and inhibiting the abnormal formation of blood clots. This is of great importance when you consider that thrombosis or the formation of abnormal blood clots, is the leading cause of heart attacks and stroke.
New evidence is emerging that green tea can even help dieters. In November, 1999, the American Journal of Clinical Nutrition published the results of a study at the University of Geneva in Switzerland. Researchers found that men who were given a combination of caffeine and green tea extract burned more calories than those given only caffeine or a placebo.
Green tea can even help prevent tooth decay. Just as its bacteria-destroying abilities can help prevent food poisoning, it can also kill the bacteria that causes dental plaque. Meanwhile, cosmetic industry is exploring the antioxidative and antibacterial properties of green tea. Anti-aging skin preparations containing green tea extract are starting to appear on the market.
Green tea contains amino acid L-theanine which produces calming effects in the brain by increasing levels of the neurotransmitters serotonin and dopamine and blocking the binding of L-glutamic acid to glutamate receptors.
The calming, anxiety reducing and mood-enhancing effects are achieved by helping to increase alpha-brain waves, electrical brain activity commonly present when a person is very relaxed, literally putting one in a better mood.
Green tea also contains the stimulating caffeine, but in much smaller quantities than coffee, something that has to be considered if one is taking green tea in the late afternoon or evening. Caffeine stimulates the nervous system and may interfere with the sleep pattern.
While brewing green tea it is vital to remember that boiling water should be avoided.
Green teas taste best when brewed at temperatures between 140°F - 185°F. The best results are achieved with pure spring or filtered water.