Isoflavone supplements exert hormonal and antioxidant effects in postmenopausal Korean women with diabetic retinopathy

There is growing evidence that soy isoflavones exert hormonal and antioxidant effects in postmenopausal women. In the present study, 12 postmenopausal Korean women with diabetic retinopathy consumed 2 g of genistein combined polysaccharides (GCP), containing 120 mg of genistein and 57 mg of daidzein, daily for 12 weeks. Blood was collected prior to and after 12 weeks of GCP supplementation for analysis of fasting blood glucose, insulin, lipid profiles, sex hormone-binding globulin (SHBG), estradiol, testosterone, free testosterone, and osteocalcin and activities of glutathione peroxidase (GSH-Px), catalase, and paraoxonase. After GCP supplementation, blood glucose, insulin, total cholesterol, triglyceride, high-density lipoprotein, and low-density lipoprotein cholesterols did not change significantly. However, there were significant increases in SHBG (P < .05) and testosterone (P < .05) and a decrease in estradiol (P < .01). Free testosterone levels were not significantly affected by GCP supplementation. After supplementation, osteocalcin decreased, but the difference was not statistically significant. Although activities of catalase and paraoxonase were unchanged, GSH-Px activity (P < .01) was increased significantly. These findings suggest that GCP supplementation may change the levels of some hormones and improve antioxidant status in postmenopausal Korean women with diabetic retinopathy.