Green tea is a rich source of polyphenols which represent approximately 30% dry weight. For centuries it has been regarded to possess significant health-promoting effects mostly because its polyphenol content .
Many studies have shown that green tea consumption is associated with enhanced cardiovascular and metabolic health. Green tea polyphenols and especially the most abundant green tea catechin, epigallocatechin gallate (EGCG) are the subjects of increasing research interest.[2,3]
In a retrospective Japanese study in 40,530 adults, the consumption of 5 or more cups of green tea per day have shown to significantly reduce mortality due to all causes (16% compared to subjects consuming less than 1 cup per day) and cardiovascular disease (26%) . The strongest reduction in mortality was observed for stroke (37%) and for cerebral infarction (51%).
In another Japanese study on 17,413 adults the risk for developing diabetes was reduced by 33% in subjects consuming 6 or more cups of green tea per day, compared to those consuming less than 1 cup per week .
A 12 week study on 70 moderately overweight subjects investigated the effects of encapsulated green tea extract (279 mg EGCG in 375 mg total catechins per day). The authors observed a 4.6% decrease in body weight, compared to baseline, and a 4.5% reduction in waist-to-hip ratio.
Wolfram, S. 2007. Effects of green tea and EGCG on cardiovascular and metabolic health. J. Am. Coll. Nutr. 26: 373S–388S.
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Stangl, Verena, et al. “Molecular targets of tea polyphenols in the cardiovascular system.” Cardiovascular research 73.2 (2007): 348-358.
Koo, Sung I., and Sang K. Noh. “Green tea as inhibitor of the intestinal absorption of lipids: potential mechanism for its lipid-lowering effect.” The Journal of nutritional biochemistry 18.3 (2007): 179-183.
Kuriyama, Shinichi, et al. “Green tea consumption and mortality due to cardiovascular disease, cancer, and all causes in Japan.” JAMA: the journal of the American Medical Association 296.10 (2006): 1255-1265.
Iso, Hiroyasu, et al. “The relationship between green tea and total caffeine intake and risk for self-reported type 2 diabetes among Japanese adults.” Annals of internal medicine 144.8 (2006): 554.
Chantre, P., and D. Lairon. “Recent findings of green tea extract AR25 (Exolise) and its activity for the treatment of obesity.” Phytomedicine 9.1 (2002): 3-8.