The effect of tea consumption on oxidative stress in smokers and nonsmokers

While the anticarcinogenic effects of tea in animal models have been report ed by several groups, human epidemiological studies examining tea consumpti on end cancer prevention have produced equivocal results, The beneficial pr operties of tea to human health may be related to the antioxidant propertie s of tea components, However, little evidence has been provided that tea co nsumption can either increase the antioxidant capacity or decrease oxidativ e stress in humans. In the present study, the effects of tea treatment (gre en tea) on biomarkers of oxidative stress were investigated in smokers acid nonsmokers in two volunteer study groups (one in China and the other in Un ited States). Green tea consumption in both study groups decreased oxidativ e DNA damage (8-OHdG in white blood cells and urine), lipid peroxidation (M DA in urine), and free radical generation (2,3-DHBA in urine) in smokers. N onsmokers (US study group) also exhibited a decrease in overall oxidative s tress.