Green tea is made from the leaves of Camellia sinensis, an evergreen plant. Both green and black teas are derived from Camellia sinensis, but the black tea leaves are fermented before drying and lose their beneficial polyphenols. According to David Steinman, writing in the March/April 1994 issue of Natural Health, dietary surveys of the Japanese, the world's leading green tea drinkers, show that people who drink four to six cups daily have a much lower incidence of liver, pancreatic, breast, lung, esophageal, and skin cancers than people who drink less green tea or none. Steinman hypothesizes that green tea prevents cancer (and possibly other diseases) by acting as an antioxidant.
Japanese researchers recently found the main physiologically active polyphenol in green tea extract, (-) epigallocatechin gallate (EGCG), appears to inhibit the growth of tumors. A. Komori, writing in the June 1993 issue of the Japanese Journal of Clinical Oncology, states that EGCG inhibits protein kinase C activation by teleocidin, a tumor promoter. Komori claims that EGCG prevents the growth of lung and breast cancer. Dr. N. Ito in a 1992 issue of Teratogeneis, Carcinogensis, & Mutagenesis, theorizes that green tea may have a sealing effect–it may block the interaction of tumor promoters, hormones, and growth factors with their receptors.
The Medical Benefits of Green Tea
1. Drinking green tea lowers the risk of liver, pancreatic, breast, lung, esophageal, and skin cancers.
2. Green tea lowers the risk of cardiovascular disease by inhibiting the production of platelets, which form atheromas (blockages) of the coronary arteries.
3. Green tea reduces the risk of stroke.
4. Green tea lowers blood sugars. Animal experiments have shown that animals who maintain moderate blood sugar levels live longer.
5. Green tea and its active components combat viruses.