Purified phytoestrogens in postmenopausal bone health: is there a role for genistein?

Objective Genistein is the main isoflavone present in soy and the one to which biological action is most often ascribed. There are suggestions that genistein could have a role as an osteoprotective agent. Hence, a review of the evidence has been undertaken. Methods MEDLINE (1966-August 2001), Allied Complementary Medicine (1985-2001), the Cochrane Library and the Database of Systematic Reviews (2nd Quarter 2001) were searched using the key words: genistein, osteoporosis, bone, isoflavones. Results Genistein appears to bind to the estrogen receptor (ER), with greatest affinity to ERbeta. In vitro it stimulates protein synthesis in osteoblast cell lines, and in animal studies it appears to be effective in preventing bone loss caused by estrogen deficiency. There are no published human studies using pure genistein. Conclusion Genistein appears to have a stimulatory effect on osteoblasts and, in some animal studies, it has been shown to exert an anabolic effect on bone. If these effects were to be demonstrated in humans, genistein would be a potentially useful oral anabolic agent for the treatment of osteoporosis.