Soy isoflavone intake inhibits bone resorption and stimulates bone formation in menopausal women: Meta-analysis of randomized controlled trials

Department of Social Medicine and Health Education, School of Public Health, Peking University, Beijing, China.
European Journal of Clinical Nutrition (Impact Factor: 2.71). 02/2008; 62(2):155-61. DOI: 10.1038/sj.ejcn.1602748
Source: PubMed


To clarify the effects of isoflavone intake on bone resorption and bone formation.
We identified randomized controlled trials related to urinary deoxypyridinoline (Dpyr, a bone resorption marker) and serum bone-specific alkaline phosphatase (BAP, a bone formation marker) listed on MEDLINE (January 1966-April 2006), the Cochrane Controlled Trials Register, EMBASE (1985-January 2006), Science Citation Index and PUBMED (updated till April 2006).
Nine studies with a total of 432 subjects were selected for meta-analysis. The urinary Dpyr concentration in subjects who consumed isoflavones decreased significantly by -2.08 nmol/mmol (95% confidence interval (CI): -3.82 to -0.34 nmol/mmol) in comparison with that in subjects who did not consume isoflavones. Isoflavone intake vs placebo intake significantly increased serum BAP by 1.48 microg/l (95% CI: 0.22-2.75 mug/l). Decreases in the urinary Dpyr concentration with isoflavone intake of <90 mg/day and with treatment lasting less than 12 weeks were -2.34 nmol/mmol (95% CI: -4.46 to -0.22 nmol/mmol) and -2.03 nmol/mmol (95% CI: -3.20 to -0.85 nmol/mmol), respectively.
Isoflavone intervention significantly inhibits bone resorption and stimulates bone formation. These favorable effects occur even if <90 mg/day of isoflavones are consumed or the intervention lasts less than 12 weeks.

  • Source
    • "Morabito et al. (2002) could see the significant results as soon as 6 months. In contrast to our results, Ma et al. (2008) reported significant changes in BALP after phytoestrogens consumption. Our former study on the effect of n-3 fatty acids on bone biomarkers resulted significant change in urine Pyd levels as soon as after 2 month n-3 fatty acid consumption (Salari et al. 2010). "
    [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.
    Full-text · Article · Sep 2011 · Age
  • Source
    • "It is reasonable to suggest that soy or its isoflavones enhance bone formation based on at least two lines of evidence: (1) soy isoflavones stimulate osteoablastic activity through activation of estrogen receptors [47, 48], and (2) soy or its isoflavones promote insulin-like growth factor-I (IGF-I) production [31]. In a recent review, Atmaca [49] stated that soy isoflavones act on both osteoblasts and osteoclasts through genomic and nongenomic pathways. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Osteoporosis is defined as a progressive systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture. Although bone mass and quality is mainly determined genetically, many other factors, including lifestyle and nutrition also have an impact on bone health. It has been suggested that dietary protein intake may be a risk factor for osteoporosis, and high-protein diets are associated with increased bone loss. Many scientists have examined the relationship between types of protein and urinary calcium excretion, and found that although animal protein was associated with increased urinary calcium excretion, soy protein was not. There is sufficient evidence suggesting soy isoflavones may have potential benefits for bone. Soy protein with naturally occurring phytoestrogens, mainly isoflavones protect against bone loss and synthetic soy ipriflavone in some studies has been shown to favorably affect, but a cause and effect relationship has not been established between the consumption of ipriflavone and maintenance of bone mineral density in post-menopausal women. Therefore it is too early to recommend it as a supplement for this group of women.
    Full-text · Article · Mar 2010 · Journal of Osteoporosis
  • Source
    • "Although the effects of isoflavones on bone metabolism appear inconsistent in randomized clinical trials, recently performed meta-analysis suggested that isoflavones contribute significantly to inhibiting bone resorption and stimulating bone formation , especially in postmenopausal women (Ma et al., 2008). However, there are still no results of randomized clinical trials concerning the effects of soy isoflavones on the fracture risk, the critical end-point for all the treatments designed to prevent or treat osteoporosis (Migliaccio & Anderson, 2003; Weaver & Cheong, 2005). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Genistein, a major phytoestrogen of soy, is considered a potential drug for prevention and treatment of postmenopausal osteoporosis. The aim of the present study was to compare the effects of genistein, estradiol and raloxifene on the skeletal system in vivo and in vitro. Genistein (5 mg/kg), estradiol (0.1 mg/kg) or raloxifene hydrochloride (5 mg/kg) were administered daily by a stomach tube to mature ovariectomized Wistar rats for 4 weeks. Bone mass, mineral and calcium content, macrometric parameters and mechanical properties were examined. Also the effects of genistein, estradiol and raloxifene (10(-9)-10(-7) M) on the formation of osteoclasts from neonatal mouse bone marrow cells and the activity of osteoblasts isolated from neonatal mouse calvariae were compared. In vivo, estrogen deficiency resulted in the impairment of bone mineralization and bone mechanical properties. Raloxifene but not estradiol or genistein improved bone mineralization. Estradiol fully normalized the bone mechanical properties, whereas genistein augmented the deleterious effect of estrogen-deficiency on bone strength. In vitro, genistein, estradiol and raloxifene inhibited osteoclast formation from mouse bone marrow cells, decreasing the ratio of RANKL mRNA to osteoprotegerin mRNA expression in osteoblasts. Genistein, but not estradiol or raloxifene, decreased the ratio of alkaline phosphatase mRNA to ectonucleotide pyrophosphatase phosphodiesterase 1 mRNA expression in osteoblasts. This difference may explain the lack of genistein effect on bone mineralization observed in ovariectomized rats in the in vivo study. Concluding, our experiments demonstrated profound differences between the activities of genistein, estradiol and raloxifene towards the osseous tissue in experimental conditions.
    Preview · Article · May 2009 · Acta biochimica Polonica
Show more