Antiresorptive Effects of Phytoestrogen Supplements Compared with Estradiol or Risedronate in Postmenopausal Women Using Ca-41 Methodology

Department of Foods and Nutrition, Purdue University, West Lafayette, Indiana 47907-2059, USA.
The Journal of Clinical Endocrinology and Metabolism (Impact Factor: 6.21). 08/2009; 94(10):3798-805. DOI: 10.1210/jc.2009-0332
Source: PubMed

ABSTRACT Reduction of ovarian estrogen secretion at menopause increases net bone resorption and leads to bone loss. Isoflavones have been reported to protect bone from estrogen deficiency, but their modest effects on bone resorption have been difficult to measure with traditional analytical methods.
In this randomized-order, crossover, blinded trial in 11 healthy postmenopausal women, we compared four commercial sources of isoflavones from soy cotyledon, soy germ, kudzu, and red clover and a positive control of oral 1 mg estradiol combined with 2.5 mg medroxyprogesterone or 5 mg/d oral risedronate (Actonel) for their antiresorptive effects on bone using novel (41)Ca methodology.
Risedronate and estrogen plus progesterone decreased net bone resorption measured by urinary (41)Ca by 22 and 24%, respectively (P < 0.0001). Despite serum isoflavone profiles indicating bioavailability of the phytoestrogens, only soy isoflavones from the cotyledon and germ significantly decreased net bone resorption by 9% (P = 0.0002) and 5% (P = 0.03), respectively. Calcium absorption and biochemical markers of bone turnover were not influenced by interventions.
Dietary supplements containing genistein-like isoflavones demonstrated a significant but modest ability to suppress net bone resorption in postmenopausal women at the doses supplied in this study over a 50-d intervention period.

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Available from: Susan Reinwald, Sep 26, 2015
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    • "The data on the long-term effects on the cardiovascular, breast, endometrial, and urogenital health, as well as bone health, are much scarcer [9]. There are clinical reports both on lack of significant effects [10, 11], and some favorable effects [12, 13] of red clover extracts on the skeletal system. Nevertheless, beneficial effects of red clover extracts on bones have been demonstrated in the experimental settings [14–16]. "
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    ABSTRACT: Some plant species belonging to Trifolium L. genus are a source of isoflavones considered to exert phytoestrogenic activities. The aim of the present study was to examine the effects of standardized extract obtained from aerial parts of Trifolium medium L., in comparison with the extract of Trifolium pratense L., on the development of estrogen deficiency-induced osteoporosis in rats. Both Trifolium extracts, at doses corresponding to 10 and 20 mg/kg of isoflavone aglycones daily, or estradiol (0.2 mg/kg daily), were administered orally to ovariectomized (OVX) rats for 4 weeks. Serum bone turnover markers, bone mass, mineralization, and mechanical properties were studied. In OVX control rats, mechanical properties of the tibial metaphysis and femoral neck were strongly worsened in comparison with sham-operated control rats, and those of femoral diaphysis were unaffected. Estradiol counteracted the worsening of the tibial strength and increases in bone turnover markers. Both extracts significantly increased the strength of the femoral diaphysis and calcium and phosphorus content in the bone mineral, but only T. pratense extract increased the strength of the tibial metaphysis. In conclusion, effects of both Trifolium extracts differed from those of estradiol. It is possible that other than isoflavone extract constituents contributed to their skeletal effects.
    Evidence-based Complementary and Alternative Medicine 11/2012; 2012(1):921684. DOI:10.1155/2012/921684 · 1.88 Impact Factor
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    • "Regarding the importance of BMD as well as bone biomarkers in bone health assessment, there are several different types of studies that assessed bone remodeling after phytoestrogens intake and their results are conflicting. Some studies in postmenopausal women reported significant decrease in bone resorption markers (Crisafulli et al. 2004; Evans et al. 2007) in contrast to the others who reported nonsignificant changes in bone resorption markers (Albertazzi et al. 2005; Wangen et al. 2000) and bone formation markers (Albertazzi et al. 2005; Weaver et al. 2009). In addition, the BMD changes Effect size meta-analysis plot [random effects] "
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    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
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