Isoflavones as Putative Anti-aging Food Factors in Asia and Effects of Isoflavone Aglycone-rich Fermented Soybeans on Bone and Glucose Metabolisms in Post-menopausal Women

摘要

Objective: Since soy isoflavone intake, high in Japanese and Asian populations was epidemiologically associated with lower risks of cardiovascular diseases(CVD), we focused on soy isoflavone effects on other risks of lifestyle-related diseases and investigated whether or not the intake of isoflavone aglycone-rich fermented soybeans affected bone and glucose metabolisms in post-menopausal women.Methods: Healthy post-menopausal women aged 47 to 70 years, 65 in total, were invited to a test diet-placebo independent parallel double-blind dietary intervention study, and were randomized for taking isoflavone aglycone-rich fermented soybean soup (isoflavone aglycone 24 mg/day) or placebo soup for 4 weeks. Blood and 24-hour urine samples were collected before and after the intake. We analyzed the markers of bone and glucose metabolisms. The subjects refrained from consuming other soybean-based foods and isoflavone supplements for 9 weeks, starting at 5 weeks in advance of the intervention.Results: We analyzed 56 subjects from whom complete 24-hour urine samples could be collected, and obtained the following results:1. Urinary total isoflavone level was significantly higher at 4 weeks in the fermented soybean group (S) than that in the placebo group (P).2. In P, the urinary excretion of deoxypyridinoline (bone resorption marker) was significantly increased at 4 weeks from the baseline value but did not show any significant change in S. In contrast the serum osteocalcin (bone formation marker) level was significantly increased at 4 weeks from the baseline value in S, but showed no significant change in P.3. Serum insulin level was significantly lower at 4 weeks in S than in P, while blood glucose levels were similar in S and P. Thus, insulin resistance (the homeostasis model assessment of insulin resistance) was significantly lower at 4 weeks in S than in P.Conclusion: Four-week intake of fermented soybean soup containing 24 mg of isofla-vone aglycone improved bone and glu