What Is It?
Catechins are flavonoid phytochemical compounds that appear predominantly in green tea. Smaller amounts of catechins are also in black tea, grapes, wine, and chocolate. Four polyphenol catechins in green tea include gallocatechin (GC), epigallocatechin (EGC), epicatechin (EC), and epigallocatechin gallate (EGCG). Due to their potent antioxidant capabilities, catechins, often referred to as “tea flavonoids,” are being investigated for their ability to prevent cancer and heart disease. In experimental models, catechins show a wide range of protective effects, including cardioprotective, chemoprotective, and anitmicrobial properties.
While black tea also has flavonoids, it seems to be green tea (unfermented) that has the higher amount of catechins. Green tea has about 27% catechins, with oolong tea (partially fermented) having about 23%, and black tea (fermented) at approximately 4% catechins. Researchers speculate that green tea’s higher concentration of catechins is due to the way it is processed. Green tea harbors important compounds that may be reduced in black tea during the drying and fermentation process that produces black tea. Polyphenols constitute about 15% to 30% of unfermented dried green tea and most of the soluble portion of tea.
Catechins exert significant antioxidant power and may prove to be important heart healthy agents in combating lipid peroxidation within cell membranes lining arterial walls and reducing formation of atherosclerotic plaque. In particular, the tea catechin, epigallocatechin gallate (EGCG), is currently being studied for its role as a chemoprotective agent. Scientists speculate that EGCG may be responsible for suppressing growth of tumors as well as inhibiting enzymes that are involved in spread of cancer cells. In fact, what distinguishes EGCG from other compounds is that it seems to have a unique ability to fight cancer at all stages, from inhibiting development of tumors, to eradicating tumor promoters, blocking chemical carcinogens and neutralizing enzymes involved in cell proliferation. Current research has shown EGCG to be as much as 100 times more potent than vitamin C and 25 time more potent than vitamin E in antioxidant power. Antimicrobial properties in green tea are also attributed to EGCG, which has been shown to repress the growth of bacteria such as helicobacter pylori, E. coli, and Staphylococcus aureus. Scientists have not yet determined specific amounts of catechins needed to exert health benefits.
David Edelberg, MD