Effect of pure genistein on bone markers and hot flushes

Objective To evaluate the effect of 90mg of daily genistein on markers of bone turnover and menopausal symptoms. Design This was a cross-over, placebo-controlled study involving 100 postmenopausal women. Subjects were randomly assigned to daily genistein or placebo for 6 weeks and crossed over to the alternative preparation for the following 6 weeks. Pure genistein was processed and encapsulated in accordance with British Pharmacopoeia standards. Each capsule contained 90mg of pure gemstein while the placebo contained just the eccipients. Results In women with significant hot flushes (score (intensity x number) >= 9), genistein reduced symptoms by 30% compared to baseline and the difference compared to placebo was statistically significant. No effect was observed on biochemical markers of bone turnover, possibly due to the short duration of each arm of the study. Genistein reduced osteocalcin, a marker of bone formation, by 3.6% compared to baseline and 0.31% compared to placebo (p=0.81 and 0.40, respectively). Genistein increased crosslink telopeptide, a marker of bone resorption, by 1.8% compared to baseline and 0.29% compared to placebo; both differences were not statistically significant (p=0.078 and 0.88, respectively). Conclusion Pure genistein at a dose of 90 mg per day appears to reduce the number of hot flushes in postmenopausal women but the effect is mild.