[Prevention of osteoporosis by foods and dietary supplements. Soybean isoflavone and bone metabolism].

Soybean isoflavones show structural similarity to estradiol and therefore are known as phytoestrogen. Recently, isoflavones have received a great deal of attention for their preventive roles against hormone dependent diseases including postmenopausal osteoporosis, hyperlipidemia and cancer. Particularly, a number of studies have reported that soybean isoflavones inhibited bone loss in both female and male osteoporotic animal models as well as in postmenopausal women. On the other hand, since a kind of tablet with concentrated isoflavones has been recently applied for foods for specified health use (FOSHU), which are functional foods permitted to label a health claim by the Ministry of Health, Labor and Welfare in Japan, Food Safety Commission submitted a report the upper limit of daily isoflavone aglycon intake from FOSHU as well as from soybean products. This report demonstrates the effects of isoflavones on bone metabolism and safety.