We have previously shown that
green tea (GT) drinking combined with
vitamin E supplementation reduced
plasma protein carbonyls and increased erythrocytes
catalase activity in exercising healthy elderly. In the present study we set out to investigate the antioxidative effects of GT drinking in an aging population. We performed an interventional, crossover, controlled prospective trial with 35 healthy elderly subjects (mean age 67.3±4.8 years), supplemented with four daily placebo
maltodextrin "
tea-bags" for 12 weeks, followed by four 1.5 g daily GT bags for another 12 weeks. Data were obtained at baseline, at the end of the placebo period, and at the end of the GT intervention period. We found that GT did not alter erythrocyte
catalase activity. However, it provided protection against 2,2'-azobis (2-amidinopropane) dihydrochloride (
AAPH)-induced oxidative
hemolysis which declined by 10.2% (p<0.001). No changes were observed in saliva oral
peroxidase enzymes. Nonetheless, saliva total
antioxidant capacity increased by 42.0% (p<0.01). Plasma oxidative products, such as
protein carbonyls,
lipid peroxides and
thiobarbituric acid reactive substances (
TBARS) were stable throughout the intervention period. We conclude that four daily cups of GT are well tolerated in elderly free living subjects. Our results demonstrate that both erythrocyte resistances to oxidation and saliva
antioxidant capacity are improved by GT drinking. The clinical implications of these oxidation modifications require further research.