According to Chinese legend the story of Green tea began in 2737 BC when Emperor Shen Nung, who was known at time as the “Devine Healer” always boiled his water before he would drink it. He had noticed that his subjects who boiled their water before drinking it seemed to have longevity and better health. One afternoon, as he knelt before his boiling water, some leaves from a nearby tree blew into the pot . The Emperor noted a delightful aroma and upon sipping the beverage, proclaimed it as “heaven sent”.
The best green tea is harvested in spring when the theanine to polyphenol ratio is the highest.
Cell and cell culture studies indicate that EGCG, and to a lesser extent other catechins in green tea, decrease oxidation of low density lipoprotein (LDL) and inhibit the proliferation of smooth muscle cell and endothelial cells, thereby potentially reducing the risk of arteriosclerosis. EGCG also prevents blood vessel and tube formation, causing cessation of cancer growth and preventing certain types of tumors from spreading.
EGCG can act on platelets and other cells to prevent platelet aggregation as shown in many experiments on isolated cells or cell cultures, suggesting that green tea polyphenols have antithrombotic action in preventing blood clots.
Based on animal studies, tea may reduce the risk of lung cancer.
Green tea has been shown to reduce damage to blood vessels in smokers.
Researchers were able to confirm the weight loss benefit of green tea in a recent study at the University of Geneva. The conclusion was that, green tea can produce weight loss through the activation of thermogenesis (producing heat by burning fat), thereby reducing obesity, one of the risk factors of heart disease
Potential mechanism for green tea's action was outlined recently by a team at the University of Wisconsin and Case Western Reserve University in Cleveland, Ohio. They found that green tea polyphenols reduce levels of insulin-like growth factor-1 (IGF-1) in prostate tumor cells. Increased levels of IGF-1 are associated with higher risk of several cancers, such as prostate, breast, lung and colon.
Topical application of the major polyphenol antioxidant in green tea (EGCG) reduces the amount of free radicals and inflammatory prostaglandins produced by immune cellsin skin in response to UVB sun rays. The results suggest that skin products containing sufficient green tea extract may help protect against UVB-induced skin aging and skin cancers.
Green tea's main antioxidant, EGCG is many times more powerful antioxidant than vitamin E. According to the National Cancer Institute antioxidants in green tea may inhibit cancer growth. Studies show that the antioxidant EGCG found in green tea plays a part in apoptosis (or cell death) of cancer cells. Remarkably the cell killing actions of the antioxidant affect only cancer cells and leaves healthy cells undamaged.