To evaluate the effect of 90 mg of daily genistein on markers of bone turnover and menopausal symptoms.
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 90 mg of pure genistein while the placebo contained just the recipients.
In women with significant hot flushes (score (intensity x number) > or = 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 cross-link 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).
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.
"In the chosen articles, five studies were analyzed for OC. In only one study, we saw the significant increase in OC level (Morabito et al. 2002) by the dose of 54-mg phytoestrogens and as early as 6 months, and the rest of the studies did not result in this way (Uesugi et al. 2002; Ye et al. 2006; Zhang et al. 2007; Albertazzi et al. 2005). Meta-analysis of these five studies resulted in no significant change in serum OC levels. "
[Show abstract][Hide abstract] ABSTRACT: Phytoestrogens as selective estrogen receptor modulators like compounds may consider as a therapeutic option in osteoporosis. In this regard, the effect of phytoestrogens on bone biomarkers was examined in several trials which their results are controversial. We aimed this meta-analysis to evaluate the net effect of phytoestrogens on bone markers. A thorough search was conducted from 2000 to 2010 in English articles. All randomized clinical trials were reviewed, and finally, 11 eligible randomized clinical trials were selected for meta-analysis. Totally 1,252 postmenopausal women were enrolled in the study by considering the changes of pyridinoline (Pyd), desoxypyridinoline (Dpyd), bone alkaline phosphatase, and osteocalcin concentrations in urine and serum after phytoestrogens consumption. The urine Pyd and Dpyd levels decreased significantly in phytoestrogens consumers. Effect size and effect size for weighted mean difference of urine Pyd levels showed -1.229171 (95% confidence interval (CI) = -1.927639 to -0.530703) and -9.780623 (95% CI = -14.240401 to -5.320845), respectively, a significant results in comparison to control group and significant results for Dpyd -0.520132 (95% CI = -0.871988 to -0.168275) and -0.818582 (95% CI = -1.247758 to -0.389407), respectively. Meta-analysis indicates that phytoestrogens intake can prevent bone resorption, but its benefits on bone formation are not significant. This favorable effect was observed in low doses and in at least 3 weeks of phytoestrogens intake.
Age 09/2011; 33(3):421-31. DOI:10.1007/s11357-010-9180-6 · 3.45 Impact Factor
"Support for this last explanation is particularly intriguing and is consistent with knowledge that the estrogenic potency of genistein is greater than that of daidzein and glycitein . Furthermore, each of the three trials that evaluated the ability of isolated genistein to alleviate hot flushes found it to be efficacious   . However, in each case, the baseline hot flush frequency was much lower than is generally recommended for these types of trials. "
[Show abstract][Hide abstract] ABSTRACT: To evaluate the efficacy of synthetic genistein for reducing the frequency and severity of hot flushes.
A 12 week randomized double-blind, placebo-controlled study in which 84 postmenopausal women received placebo or a single 30 mg dose of synthetic genistein. Outcome measures primary: percentage change in the number of daily hot flushes from pre-treatment to week 12. Secondary: duration and severity of daily hot flushes, Greene Climacteric Scale score, serum follicle stimulating hormone (FSH), 17β-estradiol and endometrial thickness.
Genistein supplemented subjects completing at least 4 weeks on trial (n=40) demonstrated a 51% reduction (9.4-4.7/day) in the number of hot flushes by week 12 compared to a 27% reduction in the placebo group (9.9-7.1/day) (p=0.026). Subjects in the genistein group also reported significantly fewer hot flushes per day (p=0.010) and a decrease in total duration of hot flushes per day (p=0.009) at week 12 versus placebo. Subjects on genistein (n=32) completing 12 weeks on trial demonstrated a 51% reduction (9.7-4.7/day) in the number of hot flushes by week 12 (p=0.049) compared to 30% reduction in the placebo group (9.8-7.0/day) and had fewer hot flushes per day and a decrease in total duration of hot flushes per day at week 12 compared to placebo (p=0.020 and p=0.017, respectively). There were no differences between groups in Greene Climacteric Scale, FSH, 17β-estradiol, endometrial thickness or adverse events.
The current study provides the first evidence that a single daily dose of 30 mg of synthetic genistein reduces hot flush frequency and duration.
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