Green Tea (Camellia Sinensis)
Green tea is tea that has undergone minimal oxidation during processing. Green tea is popular in China and Japan, and recently has become more popular in the West, which traditionally drank only black tea. A number of beneficial health effects are attributed to regular consumption of green tea and dried/powdered extracts of green tea are available as dietary supplements
Green tea is prepared by picking, lightly steaming and allowing the leaves to dry. Black tea, the most popular type of tea in the U.S., is made by allowing the leaves to ferment before drying. Due to differences in the fermentation process, a portion of the active compounds are destroyed in black tea, but remain active in green tea. There are four primary polyphenols in green tea and they are often collectively referred to as catechins. Powerful antioxidants, catechins have been shown in recent studies to fight viruses, slow aging, and have a beneficial effect on health. Clinical tests have shown that catechins destroy free radicals and have far-reaching positive effects on the entire body. Free radicals are highly reactive molecules and fragments of molecules that can damage the body at the cellular level leaving the body susceptible to cancer, heart disease, and many other degenerative diseases.
The active constituents in green tea are a family of polyphenols (catechins) and flavonols which possess potent antioxidant activity. Tannins, large polyphenol molecules, form the bulk of the active compounds in green tea, with catechins comprising nearly 90%. Several catechins are present in significant quantities; epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG) and epigallocatechin gallate (EGCG). EGCG makes up about 10-50% of the total catechin content and appears to be the most powerful of the catechins – with antioxidant activity about 25-100 times more potent than vitamins C and E. A cup of green tea may provide 10-40mg of polyphenols and has antioxidant activity greater than a serving of broccoli, spinach, carrots or strawberries. A number of commercial green tea extracts are standardized to total polyphenol content and/or EGCG content.
Green Tea lowers total cholesterol levels and improves the cholesterol profile (the ratio of LDL cholesterol to HDL cholesterol), reduces platelet aggregation, and lowers blood pressure. The polyphenols in Green Tea have also been shown to support a lower risk of several types of cancers, stimulate the production of several immune system cells, and have antibacterial properties - even against the bacteria that causes dental plaque. It is interesting to note that Green Tea supports the prevention of certain types of cancer, whereas black tea increases the risk of certain cancers, such as cancer of the rectum, gallbladder, and endometrium.