Green tea contains high levels of substances called polyphenols, known to possess strong antioxidant, anticarcinogenic, antitumorigenic, and even antibiotic properties. Preliminary studies suggest that certain green tea polyphenols may help prevent skin cancer if they are applied directly to the skin. In addition, there is some evidence that green tea constituents might help protect the skin from sun damage. Unlike normal sunscreen preparations, green tea does not physically block ultraviolet light. Rather, it seems to protect cells from damage. Because it works by such a different mechanism of action, green tea might offer synergistic benefits if combined with standard sunscreens.

Like grape seed, Ginkgo and many other phytomedicinals, green tea (Camellia sinensis) is an excellent source of polyphenolic compounds displaying a broad array of biological activities, most notably antioxidant properties that may hold value in the treatment of cardiovascular disease, diabetes, Alzheimer's and more. Of particular interest to bodybuilders and others concerned about weight loss and physical appearance are the effects of green tea extract on fat-burning (oxidative) metabolism.

Popular as a drink in Asia, green tea is one of three types of tea actually manufactured from tea leaves (the others being Oolong tea and black tea). Unlike black tea, green tea is processed in a manner that minimizes fermentation, and thereby, the catechin content (100 g/kg dry leaves). The major polyphenols in green tea are catechins, namely, epicatechin, epicatechin gallate, epigallocatechin, epicgallocatechin gallate. Green tea extract and isolated components have been found to produce thermogenic, lipolytic and other effects that may be expected to accelerate body fat loss.

Dulloo et al. (1999) recently reported that the consumption of green tea extract elevates both the metabolic rate and the rate of fat oxidation by individuals. An important component in these regards appears to be the main catechin of green tea, epigallocatechin 3-gallate (EPGC), although caffeine is also likely to be involved, perhaps synergistically. Dulloo et al. observed no effect of caffeine alone (150 mg/day) but a significant increase in metabolic rate when green tea extract was the source of caffeine. The green tea extract was administered in a capsule form. Others have found no increase in fat oxidation with caffeine alone at a dose of 250 mg/day.

Dulloo et al. (8 ) suggest that EGCG and caffeine from the tea act synergistically to produce the thermogenic response and an increase in fat oxidation. These and other studies suggest that the thermogenic response to caffeine is maximal at a dose of 200-300 mg/d. Adcocks et al. (2002) reflect on the components of green tea extract as they pertain to medical applications:

"Green tea is made from the leaves of the tea plant, Camellia sinensis. It differs from black tea in that there is no fermentation process involved and therefore none of the associated changes in chemical composition. The potential medical benefits of consuming green tea have received a great deal of attention over the past few years, most of which has been directed at a group of polyphenolic compounds called catechins. These are condensed into tannins in black tea, and are found in sources other than green tea, such as grape skins and seeds. The most abundant of the polyphenolic compounds in green tea is epigallocatechin gallate (EGCG), with other catechins such as epicatechin (EC), epigallocatechin (EGC) and epicatechin gallate (ECG) also present. The catechins are antioxidants, and are probably largely responsible for the reported antioxidant effects of green tea (7 ). They have also been found to have anti-inflammatory properties, which may be due to their ability to inhibit tumor necrosis factor (TNF) synthesis (8 ), possibly by the inhibition of kinase(s) in signaling cascades, leading to activation of certain transcription factors (9,12 ). They are also inhibitors of matrix metalloproteinases (13 ,14 ). The reported beneficial effects on a number of clinical conditions, including stroke and cerebral hemorrhage (15 ), cardiovascular and liver diseases (16 ), bacterial infections (17 ), stomach ulcers (18 ) and cancer (19 ) may be related to their antioxidant, anti-inflammatory and antiproteinase properties. "

He et al. (2001) remark further on the beneficial properties of green tea: "To date, a number of studies have shown that green tea or its constituents possess a variety of effects, including antioxidation (Matsuzaki and Hara 1985 ), antimutation (Kada et al. 1985 ), anticarcinogenesis (Fujiki et al. 1996 ), antibiotic action (Toda et al. 1989 ), antihypercholesterolemia (Muramatsu et al. 1986 ), antihypertension (Hara and Tonooka 1990 ), antihyperglycemia (Shimizu et al. 1988 ) and anti-inflammatory action (Sagesaka et al. 1996 ). In addition, we demonstrated that green tea could suppress D-galactosamine (GalN)3 -induced liver injury in rats (Sugiyama et al. 1998 ). Our recent studies showed that the protective effect of green tea against GalN-induced liver injury was ascribed mainly to flavonoid glycosides, theanine and soluble dietary fibers, whereas the effect of tea catechins (tea polyphenols), characteristic constituents of teas, was relatively weak (He et al. 2000 , Sugiyama et al. 1999 , Wada et al. 1999 ).

REFERENCES

Adcocks C, Collin P, Buttle DJ (2002). Catechins from Green Tea (Camellia sinensis) Inhibit Bovine and Human Cartilage Proteoglycan and Type II Collagen Degradation In Vitro. J Nutr, 132: 341.

Dulloo AG, Duret C, Rohrer D et al. (1999). Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation. Am J Clin Nutr, 70: 1040.

He P, Noda Y, Sugiyama K (2001). Green Tea Suppresses Lipopolysaccharide-Induced Liver Injury in D-Galactosamine Sensitized Rats. J Nutr, 131: 1560.

Suggested Doses
250 mg to 500 mg EGCG content daily, or as desired. Usage ranges from 250 mg to 2.5 g per day of EGCG content in studies reporting significant results.

Safety Issues
Green tea extract is non-toxic both in acute dosage and high long-term dosage (no significant effect on weight gain at 2% of the diet in 3 months in rats). It has no potential for causing mutations or birth defects, and has no adverse effect on fertility, pregnancy or nursing.

GREEN TEA DECAFFEINATED

Green Tea (Camellia Sinensis) contains catechin polyphenols which possesses powerful antioxidant activity, anti-cancer properties, anti-platelet aggregation activity, collagen stabilization and hepatic support. Green Tea may be used for the treatment of prevention of certain cancers; of the gastrointestinal tract, stomach, small intestine, pancreas, colon, lung, and estrogen related cancers. Also may be useful for arteriosclerosis.