Soybean and green tea polyphenols improve immune function and redox status in very old ovariectomized mice.

In previous work we have observed that ovariectomy in rodents, a good model of mimicking human ovarian hormone loss, causes premature aging of the immune system. The prooxidative and inflammatory state that underlies the aging process is the base of that premature immunosenescence. It has been found that nutritional interventions with polyphenolic antioxidants constitute a good alternative to rejuvenate age-affected immune functions. In this study, we administered a diet supplemented with polyphenols (coming from soybean isoflavones and green tea) to sham-operated and ovariectomized mature mice for 15 weeks, until they reached a very old age. We have studied the effect of this supplementation on a broad range of parameters of immune function (in macrophages and lymphocytes) and oxidative stress (enzymatic and nonenzymatic antioxidant defences, oxidant compounds, and lipid peroxidation damage) in peritoneal leukocytes. The results showed that ovariectomy accelerates the age-related impairment of immune functions in very old mice as well as the oxidative and proinflammatory imbalance, and that the administration of soybean isoflavones and green tea improve the immune and redox state in these animals. Because the immune system is a good marker of health and a predictor of longevity, we suggest that an adequate nutritional treatment with polyphenols could be a highly recommended tool to fight against the detrimental effects of the lack of female sex hormones, through an improvement of the immune cell functions and redox state.