Soy isoflavones attenuate bone loss in early postmenopausal Chinese women : a single-blind randomized, placebo-controlled trial

Isoflavone intervention and its impact on bone mineral density in postmenopausal women: a systematic review and meta-analysis of randomized controlled trials

Due to estrogen deficiency, postmenopausal women may suffer from an imbalance in bone metabolism that leads to bone fractures. Isoflavones, a type of phytoestrogen, have been suggested to improve bone metabolism and increase bone mass. Therefore, isoflavones are increasingly recognized as a promising natural alternative to hormone replacement therapy for postmenopausal women who face a heightened risk of osteoporosis and are susceptible to bone fractures.

PURPOSE

This study aimed to evaluate the efficacy of isoflavone interventions on bone mineral density (BMD) in postmenopausal women by means of systematic review and meta-analysis.

METHODS

The electronic database searches were performed on PubMed, Embase, Scopus, and Cochrane Library databases, covering literature up to April 20, 2023. A random-effects model was used to obtain the main effect estimates, with a mean difference (MD) and its 95% confidence interval (CI) as the effect size summary. The risk of bias assessment was conducted using the Risk of Bias 2 (RoB2) tool.

RESULTS

A total of 63 randomized controlled trials comparing isoflavone interventions (n = 4,754) and placebo (n = 4,272) were included. The results indicated that isoflavone interventions significantly improved BMD at the lumbar spine (MD = 0.0175 g/cm2; 95% CI, 0.0088 to 0.0263, P < 0.0001), femoral neck (MD = 0.0172 g/cm2; 95% CI, 0.0046 to 0.0298, P = 0.0073), and distal radius (MD = 0.0138 g/cm2; 95% CI, 0.0077 to 0.0198, P < 0.0001) in postmenopausal women. Subgroup analysis showed that the isoflavone intervention was effective for improving BMD when the duration was ≥ 12 months and when the intervention contained genistein of at least 50 mg/day.

CONCLUSION

This systematic review and meta-analysis suggests that isoflavone interventions, especially those containing genistein of at least 50 mg/day, can effectively enhance BMD in postmenopausal women.

The Effects of Polyphenols on Bone Metabolism in Postmenopausal Women: Systematic Review and Meta-Analysis of Randomized Control Trials

Osteoporosis is a condition favored by the postmenopausal decline in estrogen levels and worsened by oxidative stress (OS). Polyphenols are natural compounds abundantly found in fruits and vegetables, and they exert antioxidant and hormonal effects that could be useful in osteoporosis prevention, as suggested by epidemiological studies showing a lower incidence of fractures in individuals consuming polyphenol-rich diets. The aim of our meta-analysis is to evaluate the effects of polyphenols on bone mineral density (BMD, primary endpoint) and bone turnover markers (BTMs, secondary endpoint) in postmenopausal women. Twenty-one randomized control trials (RCTs) were included in our analysis after in-depth search on PubMed, EMBASE, and Scopus databases. We found that supplementation with polyphenols for 3-36 months exerted no statically significant effects on BMD measured at lumbar spine (sMD: 0.21, 95% CI [-0.08 to 0.51], p = 0.16), femoral neck (sMD: 0.16, 95% CI [-0.23 to 0.55], p = 0.42), total hip (sMD: 0.05, 95% CI [-0.14 to 0.24], p = 0.61), and whole body (sMD: -0.12, 95% CI [-0.42 to 0.17], p = 0.41). Subgroup analysis based on treatment duration showed no statistical significance, but a significant effect on lumbar BMD emerged when studies with duration of 24 months or greater were analyzed separately. On the other hand, we found a significantly slight increase in bone-specific alkaline phosphatase (BALP) levels (sMD: 1.27, 95% CI [1.13 to 1.42], p < 0.0001) and a decrease in pyridinoline (PD) levels (sMD: -0.58, 95% CI [-0.77 to -0.39], p < 0.0001). High heterogeneity among studies and unclear risk of bias in one third of the included studies emerged. A subgroup analysis showed similar effects for different duration of treatment and models of dual-energy X-ray absorptiometry (DXA) scanner. More robust evidence is needed before recommending the prescription of polyphenols in clinical practice.

A comparative study on inclusion complex formation between formononetin and β-cyclodextrin derivatives through multiscale classical and umbrella sampling simulations

Formononetin, a naturally occurring isoflavone exhibits a wide range of therapeutic applications including antioxidant, anti-tumor, antiviral, anti-diabetic and neuroprotective activities. However, the low hydro-solubility of formononetin has limited its prospective use in cosmetic, neutraceutical and pharmaceutical industries. Cyclodextrins (CDs), especially β-CD and its derivatives have emerged as promising agents to improve the water solubility of poorly hydrosoluble compounds by the formation of inclusion complexes. We employed multiscale (1000 ns) explicit solvent and umbrella sampling molecular dynamics (MD) simulations to study the interactions and thermodynamic parameters of inclusion complex formation between formononetin and five most commonly used β-CD derivatives. Classical MD simulations revealed two possible binding conformations of formononetin inside the central cavity of hydroxypropyl-β-CD (HP-β-CD), randomly methylated-β-CD (ME-β-CD), and sulfobutylether-β-CD (SBE-β-CD). The binding conformation with the benzopyrone ring of formononetin inside the central cavity of β-CD derivatives was more frequent than the phenyl group occupying the hydrophobic cavity. These interactions were supported by a variety of non-bonded contacts including hydrogen bonds, pi-lone pair, pi-sigma, and pi-alkyl interactions. Formononetin showed favorable end-state MD-driven thermodynamic binding free energies with all the selected β-CD derivatives, except succinyl-β-CD (S-β-CD). Furthermore, umbrella sampling simulations were used to investigate the interactions and thermodynamic parameters of the host-guest inclusion complexes. The SBE-β-CD/formononetin inclusion complex showed the lowest binding energy signifying the highest affinity among all the selected host-guest inclusion complexes. Our study could be used as a standard for analyzing and comparing the ability of different β-CD derivatives to enhance the hydro-solubility of poorly soluble molecules.

Daidzein Ameliorates Cerebral Ischemic-reperfusion Induced Neuroinflammation in Wistar Rats via Inhibiting NF-κB Signaling Pathway

Background

Cerebral ischemia is a condition of acute brain damage due to the depletion of oxygenated blood supply to cerebral tissues. Daidzein is an isoflavonoid predominantly present in soya, Pueraria species, and red cloves. Traditional Chinese medicine utilizes daidzein to alleviate diseases such as inflammation, hyperglycemia, gastric diseases, allergies and aches. The neuroprotective effect of daidzein on cerebral ischemic conditions and its mechanism of action was not yet elucidated.

Materials and Methods

24 healthy male adult Wistar rats were grouped into four and the control rats were sham-operated, cerebral ischemic-reperfusion induced rats subjected to middle cerebral artery occlusion (MCAO). Low- and high-dose daidzein rats were treated with 25 and 50 mg/kg daidzein respectively for 7 consecutive days before the induction of cerebral ischemic reperfusion. On completion of treatment, the rats were assessed for neurological deficit scoring and then euthanized for further analysis. The percentage of brain water content and cerebral infarct was evaluated. The ability of daidzein on preventing oxidative stress-induced damage was assessed by quantifying lipid peroxidation and antioxidant levels. The neuroprotective Daidzein was evaluated by measuring the acetylcholinesterase activity and brain ATP levels. The anti-inflammatory role of Daidzein was measured by quantifying the nitric oxide (NO) and inflammatory cytokines. Further, the anti-ischemic role of Daidzein was confirmed by estimating nuclear factor-kappa B (NF-κB) p65 and Caspase 3 levels.

Results

Daidzein treatment significantly prevented brain edema and cerebral infarction and neurological deficit in cerebral I/R injured rats. It also scavenged the free radicals and prevented the decline in antioxidant levels of ischemic rats. Daidzein decreased the acetylcholinesterase activity, NO, and inflammatory and significantly increased the brain ATP levels signifying its neuroprotective role in ischemic-induced rats. The reduction in the levels of NF-κB p65 and Caspase 3 confirms daidzein prevents neuroinflammation and neuronal apoptosis in ischemic rats.

Conclusion

Overall our analysis confirms daidzein is a potent neuroprotective drug which can effectively inhibit postischemic complications.

The Role of Soy Isoflavones in the Prevention of Bone Loss in Postmenopausal Women: A Systematic Review with Meta-Analysis of Randomized Controlled Trials

The aim of the report was to determine the effects of soy isoflavones on lumbar spine, femoral neck, and total hip bone mineral density (BMD) in menopausal women. MEDLINE (PubMed), EMBASE, and Cochrane Library databases were searched for articles published in English during 1995–2019. Studies were identified and reviewed for inclusion and exclusion eligibility. Weighted mean differences (WMD) were calculated for each study and were pooled by using the random effects model. Eighteen randomized controlled trials were selected for meta-analysis. Different types of soy phytoestrogens, i.e., genistein extracts, soy isoflavones extracts, soy protein isolate, and foods containing diverse amounts of isoflavones were used in the studies. The analysis showed that daily intake of 106 (range, 40–300) mg of isoflavones for 6–24 months moderately but statistically significantly positively affects BMD, compared with controls: lumbar spine WMD = 1.63 (95% CI: 0.51 to 2.75)%, p = 0004; femoral neck WMD = 1.87 (95% CI: 0.14 to 3.60)%, p = 0.034; and total hip WMD = 0.39 (95% CI: 0.08 to 0.69)%, p = 0.013. Subgroups analyses indicated that the varying effects of isoflavones on BMD across the trials might be associated with intervention duration, racial diversity (Caucasian, Asian), time after menopause, form of supplements (especially genistein), and dose of isoflavones. Our review and meta-analysis suggest that soy isoflavones are effective in slowing down bone loss after menopause.

The effect of Cissus quadrangularis L. on delaying bone loss in postmenopausal women with osteopenia: A randomized placebo-controlled trial

BACKGROUND

Osteopenia refers to bone density that is not normal but also not as low as that noted in osteoporosis. Osteopenia leads to osteoporosis and increases the risk of fractures. Current research is focused on agents that will prevent or slow the progression of bone loss. On the basis of published evidence, Cissus quadrangularis (CQ) might potentially provide a novel natural treatment for osteopenia.

PURPOSE

To determine the effect of 24 weeks of consecutive treatment with CQ on delaying bone loss and safety in postmenopausal women (PMW) with osteopenia.

METHODS

This study is a randomized, placebo-controlled trial. Here, 134 enrolled PMW with osteopenia (> 40 years and having no period for 1-10 years) received CQ at 1.2 (CQ1.2) or 1.6 g/day (CQ1.6) or placebo. The %change in bone mineral density (BMD) at the lumbar spine (L1-L4), femoral neck, and total hip served as the primary outcome. The %change in bone turnover markers (BTMs), including C-terminal telopeptide of type 1 collagen (CTX) and procollagen type 1 amino-terminal propeptide (P1NP), was the secondary outcome. These outcomes were compared between the CQ vs. placebo group at weeks 12 and 24. The least significant change (LSC) was used to monitor clinical changes. The adverse events (AE) were monitored.

RESULTS

A total of 108 participants completed this study. The %BMD changes in the CQ-treated groups did not differ at any site after 24 weeks compared to the placebo. Statistically significant differences were detected in CQ1.6 at the lumbar spine (0.011 ± 0.025 g/cm², p = 0.008) and CQ1.2 at the femoral neck (-0.015 ± 0.036 g/cm², p = 0.024) compared to baseline, but these changes did not exceed the LSC. Reduced bone remodeling activity was detected in both CQ-treated groups. Compared to the placebo, the %P1NP change was significantly reduced in CQ1.6 (-2.46 ± 26.05%; p < 0.01) at week 12 and in CQ1.2 (-3.36 ± 29.47%; p < 0.01) and CQ1.6 (-9.95 ± 22.22%; p < 0.01) at week 24. These results correlated with the within-group comparison, which showed a continuously significant increase in both BTMs in the placebo group. However, a stable CTX and a significant reduction in P1NP (p < 0.05) were detected in both CQ-treated groups. This reduction exceeded the LSC of P1NP. The incidence of adverse events did not differ among the three groups.

CONCLUSION

This is the first clinical report that showed a promising effect on delaying bone loss of orally administration of CQ for 24 weeks, as indicated by a slower bone remodeling process via a reduction in BTMs. However, no change in BMD was observed.

Focusing on Formononetin: Recent Perspectives for its Neuroprotective Potentials

Nervous system is the most complex system of the human body, hence, the neurological diseases often lack effective treatment strategies. Natural products have the potential to yield unique molecules and produce integrative and synergic effects compared to standard therapy. Mounting evidence has shown that isoflavonoids contained in traditional medicinal plant or dietary supplementation may play a crucial role in the prevention and treatment of neurological diseases due to their pronounced biological activities correlating to nervous system. Formononetin, a non-steroidal isoflavonoid, is a bioactive constituent of numerous medicinal plants such as red clover (Trifolium pratense) and Astragalus membranaceus. Emerging evidence has shown that formononetin possesses considerable anti-inflammatory, antioxidant and anti-cancer effects. This review intends to analyze the neuropharmacological potential of formononetin on the therapy of nervous system disorders. The neuroprotective properties of formononetin are observed in multiple neurological disorders including Alzheimer’s disease, dementia, cerebral ischemia, traumatic brain injury, anxiety, and depression. The beneficial effects of formononetin are achieved partially through attenuating neuroinflammation and oxidative stress via the related signaling pathway. Despite its evident effects in numerous preclinical studies, the definite role of formononetin on humans is still less known. More well-designed clinical trials are required to further confirm the neuroprotective efficacy and safety profile of formononetin before its application in clinic.

Crystal structure of (E)-ethyl 2-((4-oxo-4H-chromen-3-yl)methyleneaminooxy)acetate, C14H13NO5

C14H13NO5, monoclinic, P21 (no. 4), a = 4.6967(7) Å, b = 10.7175(16) Å, c = 12.945(2) Å, β = 94.827(8)°, V = 649.30(17) Å3, Z = 2, R gt (F) = 0.0577, wR ref (F 2) = 0.1302, T = 223(2) K.

3-(4-Methyl-phen-yl)-4H-chromen-4-one

In the title compound, C16H12O2, the dihedral angle formed between the plane of the chromenone ring system (r.m.s. deviation = 0.031 Å) and the pendant benzene ring is 31.09 (5)°. In the crystal, weak C-H⋯O hydrogen bonds link the mol-ecules into C(6) chains propagating along the a-axis direction.

Effects of Soy Isoflavones on Biochemical Markers of Bone Metabolism in Postmenopausal Women: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

This systematic review and meta-analysis of randomized controlled trials was performed to more completely assess potential changes in bone turnover marker levels in postmenopausal women during the intake of soy isoflavones. PubMed (Medline) and EMBASE were searched for relevant studies, and their quality was evaluated according to Cochrane criteria. The levels of markers were evaluated in a total of 1114 women who ingested mean daily doses of 98.2 mg (30.9 to 300) of soy isoflavones for 3 to 24 months, in comparison to those of 1081 subjects who used a placebo. Ten, eighteen, eight, and fourteen comparison studies were finally selected for an estimation of the effects on osteocalcin (OC), bone alkaline phosphatase (BAP), pyridinoline (PYD), and deoxypyridinoline (DPD), respectively. A summary of the results of intervention was as follows: 4.16%, 95% CI: -7.72-16.04, p = 0.49 for OC; 5.50%, 95% CI: -3.81-14.82, p = 0.25 for BAP; -12.09%, 95% CI: -25.37-1.20, p = 0.07 for PYD; and -7.48%, 95% CI: -15.37-0.41, p = 0.06 for DPD. The meta-analysis of the included studies revealed some statistically insignificant observations that soy isoflavones intake is associated with a trend in increased levels of OC and BAP, as well as a trend in reduced levels of PYD and DPD. Soy isoflavones may have a beneficial effect on bone formation markers, but this requires extensive multi-center research.

Botanicals in Postmenopausal Osteoporosis

Osteoporosis is a systemic bone disease characterized by reduced bone mass and the deterioration of bone microarchitecture leading to bone fragility and an increased risk of fractures. Conventional anti-osteoporotic pharmaceutics are effective in the treatment and prophylaxis of osteoporosis, however they are associated with various side effects that push many women into seeking botanicals as an alternative therapy. Traditional folk medicine is a rich source of bioactive compounds waiting for discovery and investigation that might be used in those patients, and therefore botanicals have recently received increasing attention. The aim of this review of literature is to present the comprehensive information about plant-derived compounds that might be used to maintain bone health in perimenopausal and postmenopausal females.

Effects of Dietary Phytoestrogens on Hormones throughout a Human Lifespan: A Review

Dietary phytoestrogens are bioactive compounds with estrogenic activity. With the growing popularity of plant-based diets, the intake of phytoestrogen-rich legumes (especially soy) and legume-derived foods has increased. Evidence from preclinical studies suggests these compounds may have an effect on hormones and health, although the results of human trials are unclear. The effects of dietary phytoestrogens depend on the exposure (phytoestrogen type, matrix, concentration, and bioavailability), ethnicity, hormone levels (related to age, sex, and physiological condition), and health status of the consumer. In this review, we have summarized the results of human studies on dietary phytoestrogens with the aim of assessing the possible hormone-dependent outcomes and health effects of their consumption throughout a lifespan, focusing on pregnancy, childhood, adulthood, and the premenopausal and postmenopausal stages. In pregnant women, an improvement of insulin metabolism has been reported in only one study. Sex hormone alterations have been found in the late stages of childhood, and goitrogenic effects in children with hypothyroidism. In premenopausal and postmenopausal women, the reported impacts on hormones are inconsistent, although beneficial goitrogenic effects and improved glycemic control and cardiovascular risk markers have been described in postmenopausal individuals. In adult men, different authors report goitrogenic effects and a reduction of insulin in non-alcoholic fatty liver patients. Further carefully designed studies are warranted to better elucidate the impact of phytoestrogen consumption on the endocrine system at different life stages.

Soy isoflavones prevent bone resorption and loss, a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Osteoporosis is a common bone disease characterized by reduced bone mass resulting from continuous bone resorption.

METHODS

PubMed, Scopus, and Embase were searched to find published trials on the effect of soy isoflavones on bone mineral density (BMD) and bone turnover markers (bone-specific alkaline phosphatase, osteocalcin, osteoprotegerin, pyridinoline, deoxypyridinoline, C-telopeptide, and N-telopeptide). Random-effects inverse-variance model was used to calculate the pooled effects.

RESULTS

A total of 5313 articles were found, screened, and assessed for eligibility, and finally 52 trials were included in the meta-analysis. Consumption of soy isoflavones caused significant improvement in BMD of lumbar spine (mean difference (MD) = 0.76%; 95% CI: 0.09, 1.42%; p = 0.03), hip (MD = 0.22%; 95% CI: 0.02, 0.42%; p = 0.04), and femoral neck (MD = 2.27%; 95% CI: 1.22, 3.31%; p < 0.001). Subgroup analysis showed that in all 3 sites, the improvement was significant in normal weight subjects and interventions longer than a year, although trial location and dosage were also factors influencing isoflavones' impact on BMD. Among markers of bone turnover, osteoprotegerin (MD = 5.79; 95% CI: 3.08, 8.51 pg/ml; p < 0.001), pyridinoline (MD = -5.13; 95% CI: -7.76, -2.50 nmol/mmol; p < 0.001), and C-telopeptides (MD = -0.08; 95% CI: -0.16, -0.00 ng/ml; p = 0.04) were favorably affected by isoflavones while osteocalcin and bone alkaline phosphatase did not change. Subgroup analysis of bone markers showed that in overweight/obese individuals and dosages <90 mg/day, isoflavones are more effective.

CONCLUSIONS

Soy isoflavones prevent osteoporosis-related bone loss in any weight status or treatment duration. They increase BMD in normal weight subjects and diminish bone resorption in overweight/obese individuals. Although bone resorption may be decelerated over short-term isoflavone consumption, periods longer than a year are probably needed to affect BMD. Isoflavones also appear benefits on bone in any dose or subjects' ethnicity.

Isoflavones

Phytoestrogens are naturally occurring nonsteroidal phenolic plant compounds that, due to their molecular structure and size, resemble vertebrate steroids estrogens. This review is focused on plant flavonoids isoflavones, which are ranked among the most estrogenic compounds. The main dietary sources of isoflavones for humans are soybean and soybean products, which contain mainly daidzein and genistein. When they are consumed, they exert estrogenic and/or antiestrogenic effects. Isoflavones are considered chemoprotective and can be used as an alternative therapy for a wide range of hormonal disorders, including several cancer types, namely breast cancer and prostate cancer, cardiovascular diseases, osteoporosis, or menopausal symptoms. On the other hand, isoflavones may also be considered endocrine disruptors with possible negative influences on the state of health in a certain part of the population or on the environment. This review deals with isoflavone classification, structure, and occurrence, with their metabolism, biological, and health effects in humans and animals, and with their utilization and potential risks.

A systematic review and meta-analysis of the effects of isoflavone formulations against estrogen-deficient bone resorption in peri- and postmenopausal women

Background: Age-related estrogen deficiency leads to accelerated bone resorption. There is evidence that, through selective estrogen receptor modulation, isoflavones may exert beneficial effects against estrogen-deficient bone loss. Isoflavone aglycones show higher bioavailability than their glycosidic counterparts and thus may have greater potency.Objective: To summarize evidence, we executed a systematic review and meta-analysis examining isoflavone therapies and bone mineral density (BMD) loss in peri- and postmenopausal women.Design: We systematically searched EMBASE and PubMed for randomized controlled trials (RCTs) evaluating isoflavone therapies for treating BMD loss at the lumbar spine and femoral neck in estrogen-deficient women. Separate meta-analyses were carried out with the use of random-effects models for the lumbar spine and femoral neck for all studies providing isoflavones as aglycones.Results: Twenty-six RCTs (n = 2652) were included in the meta-analysis. At the lumbar spine, isoflavone treatment was associated with a significantly (P < 0.00001) higher weighted mean difference (WMD) of BMD change of 0.01 (95% CI: 0.01, 0.02) than the control. For the femoral neck (18 RCTs, n = 1604), isoflavone treatment showed a significantly (P < 0.01) higher WMD of BMD change of 0.01 (95% CI: 0.00, 0.02) compared with the control. When isolating studies that provide isoflavone aglycones in their treatment arm, the average effect was further significantly increased at the spine (5 RCTs, n = 682) to 0.04 (P < 0.00001; 95% CI: 0.02, 0.05) and femoral neck (4 RCTs, n = 524) to 0.03 (P < 0.05; 95% CI: 0.00, 0.06) compared with the control. This protective effect against bone loss disappeared when only studies with formulations comprising predominantly isoflavone glycosides were included.Conclusions: Isoflavone treatments exert a moderately beneficial effect against estrogen-deficient bone loss in women. The effect appears dependent on whether isoflavone treatments are in aglycone form; we conclude that beneficial effects against bone loss may be enhanced for isoflavone aglycones.

The Effect of Short-term Treatment with Fennel on Bone Density in Postmenopausal Women: A Randomized Controlled Trial

Objectives

The goal of this study is to assess the effect of fennel on bone density.

Methods

This was a double-blind, randomized, placebo-controlled trial, which studied sixty eligible postmenopausal women, who were randomly assigned to fennel and placebo groups. Then, the dual energy X-ray absorptiometry was utilized to measure bone mineral density (BMD) and bone mineral content (BMC) of the spine, femoral neck, intertrochanter, and trochanter at the baseline and after three-month follow-up.

Results

The mean BMD and BMC at lumbar spine (P = 0.14, P = 0.504), total hip femoral (P = 0.427, P = 0.471), trochanter (P = 0.075, P = 0.07), intertrochanter, (P = 0.864, P = 0.932) and femoral neck (P = 0.439, P = 0.641) was not significantly different between the fennel and placebo groups.

Conclusions

The results of this study did not approve the effect of fennel on bone density in post-menopausal women. However, to gain deeper insights, further studies with longer durations and larger sample sizes are recommended.

Effects of phytoestrogens on bone mineral density during the menopause transition: a systematic review of randomized, controlled trials

INTRODUCTION

Menopause is associated with increased bone resorption and decreased bone mineral density (BMD). Phytoestrogens are believed to prevent bone loss. This study reviewed relevant randomized, controlled trials to determine the effects of phytoestrogens on BMD in postmenopausal women.

METHODS

In order to perform this systematic review, PubMed, Science Direct, Scopus, Cochrane Library, ISI Web of Knowledge, and ProQuest databases were searched for articles published during 2005-2016. The main keywords used during the searches were "phytoestrogen" and "bone mineral density" and "menopause". The Cochrane Risk of Bias Assessment Tool was used to evaluate the quality of the selected studies and to assess the risk of bias.

RESULTS

A total of 23 eligible studies were included in this systematic review. Most selected studies used a double-blind, placebo-controlled design. In total, 3494 participants were enrolled in the selected trials. Different types of soy isoflavone extracts, including genistein extracts (either alone or in combination with daidzein), dietary products containing different amounts of phytoestrogens, and red clover extracts were used in the designed interventions. The duration of the interventions ranged from 7 weeks to 3 years. In most studies, the primary outcome was the efficacy of the designed intervention which was assessed through measuring whole body or regional BMD or bone mineral content, T-scores, and biomarkers of bone metabolism.

CONCLUSIONS

Isoflavones probably have beneficial effects on bone health in menopausal women. Nevertheless, there were controversial reports about changes in BMD. Supplementation with a phytoestrogen can probably prevent the reduction in BMD and maintain a healthy bone structure during menopause.

Perimenopausal syndrome and mood disorders in perimenopause: prevalence, severity, relationships, and risk factors

Limited information was focused on perimenopausal syndrome and mood disorders (depression and anxiety) in a specific population: perimenopausal women. We aimed to investigate the prevalence and severity of perimenopausal syndrome and mood disorders, and to analyze their relationships and risk factors in perimenopausal women in Shanghai, China.A cross-sectional study was performed on 1062 women aged 40 to 60 years from 3 communities. The general conditions questionnaire, Kupperman index, self-rating depression scale, and self-rating anxiety scale were used. A multivariable logistic regression analysis was performed to identify risk factors for perimenopausal syndrome and mood disorders.The prevalence of perimenopausal syndrome, depression and anxiety, which were primarily associated with mild symptoms, was 10.92%, 25.99%, and 12.62%, respectively. The differences in the prevalence and severity of perimenopausal syndrome, in the prevalence of depression, and in the severity of anxiety in different age groups were statistically significant (P < 0.001, P = 0.028, P = 0.003, P = 0.002, respectively). The relationships between perimenopausal syndrome and mood disorders were strong and positive (P < 0.001). It was found that age, employment status, personality characteristics, menstruation, and constipation were risk factors for perimenopausal syndrome, but monthly household income was a protective factor. Also, higher income and better medical insurance were beneficial to depression. However, disharmonious family relationships, irregular menstruation, constipation, and severity of perimenopausal syndrome were harmful to depression. For anxiety, attitudes to children status, cesarean section times, and constipation were risk factors.We concluded that perimenopausal syndrome and mood disorders are common in perimenopausal women in Shanghai, whose associations are strong and positive. Many risk factors are associated with and shared between perimenopausal syndrome and mood disorders. Therefore, appropriate management of perimenopause is needed to alleviate the conditions.

Hepatoprotective Effects of Soybean Embryo by Enhancing Adiponectin-Mediated AMP-Activated Protein Kinase α Pathway in High-Fat and High-Cholesterol Diet-Induced Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD), which is characterized by >5% deposition of triglycerides in hepatocytes, is often referred as a major risk factor for obesity, type 2 diabetes, and hypertension. We investigated the hepatoprotective effect of whole soybean embryos containing bioactive substances such as isoflavones and soyasaponins. For this study, mice were randomly allocated into four groups that were fed different diets for 10 weeks: normal diets and high-fat and high-cholesterol diets (HD), and HD with 10% or 20% soybean embryo powder (10SE-HD and 20SE-HD). Hepatic superoxide dismutase and glutathione peroxidase activity of the experimental groups increased during the period of the study (P < .05). Hepatic mRNA expressions of tumor necrosis factor α, nuclear factor (erythroid-derived 2)-like 2, and Caspase 3 were decreased when soybean embryos were increased in the mice's diets. Both of the soybean embryo-treated groups showed significantly decreased serum and liver triglyceride and total cholesterol. Adiponectin, AMP-activated protein kinase (AMPK) α, hydroxymethylglutaryl-CoA reductase, sterol regulatory element-binding protein-1c, fatty acid synthase, and apolipoprotein B mRNA expressions were decreased in the mice that were fed soybean embryos. We suggest that the regular supplementation of soybean embryos might be a useful treatment for preventing NAFLD and associated complications through upregulation of adiponectin-mediated AMPKα pathway parameters, which are implicated in antioxidant, anti-inflammatory, and lipid metabolism activities.

Soy Isoflavones and Osteoporotic Bone Loss: A Review with an Emphasis on Modulation of Bone Remodeling

Osteoporosis is an age-related disorder that affects both women and men, although estrogen deficiency induced by menopause accelerates bone loss in older women. As the demographic shifts to a more aged population, a growing number of men and women will be afflicted with osteoporosis. Since the current drug therapies available have multiple side effects, including increased risk of developing certain types of cancer or complications, a search for potential nonpharmacologic alternative therapies for osteoporosis is of prime interest. Soy isoflavones (SI) have demonstrated potential bone-specific effects in a number of studies. This article provides a systematic review of studies on osteoporotic bone loss in relation to SI intake from diet or supplements to comprehensively explain how SI affect the modulation of bone remodeling. Evidence from epidemiologic studies supports that dietary SI attenuate menopause-induced osteoporotic bone loss by decreasing bone resorption and stimulating bone formation. Other studies have also illustrated that bone site-specific trophic and synergistic effects combined with exercise intervention might contribute to improve the bioavailability of SI or strengthen the bone-specific effects. To date, however, the effects of dietary SI on osteoporotic bone loss remain inconclusive, and study results vary from study to study. The current review will discuss the potential factors that result in the conflicting outcomes of these studies, including dosages, intervention materials, study duration, race, and genetic differences. Further well-designed studies are needed to fully understand the underlying mechanism and evaluate the effects of SI on osteoporosis in humans.

Review article: health benefits of some physiologically active ingredients and their suitability as yoghurt fortifiers

The article is concerned with health benefits of two main physiologically active ingredients namely, Isoflavones and γ-Aminobutyric acid, with emphasis on their fitness for fortification of yoghurt to be consumed as a functional food. Isoflavones (ISO) are part of the diphenol compounds, called "phytoestrogens," which are structurally and functionally similar to estradiol, the human estrogen, but much less potent. Because of this similarity, ISO were suggested to have preventive effects for many kinds of hormone-dependent diseases. In nature, ISO usually occur as glycosides and, once deconjugated by the intestinal microflora, the ISO can be absorbed into the blood. At present, it seems convincing their possible protective actions against various cancers, osteoporosis and menopausal symptoms and high levels of blood cholesterol as well as the epidemiological evidence. Γ-Aminobutyric acid (GABA), it is an amino acid that has long been reported to lower blood pressure by intravenous administration in experimental animals and in human subjects. GABA is present in many vegetables and fruits but not in dairy products. GABA was reported to lower blood pressure in people with mild hypertension. It was suggested that low-dose oral GABA has a hypotensive effect in spontaneously hypertensive. Yoghurt beyond its ability to be probiotic food via its culturing with the gut strains, it could further carry more healthy benefits when it was fortified with physiological active ingredients, especially GABA versus ISO preferring, whether, bacteriologically or biochemically, a fortification level of 50 mg ISO/kg or 200 mg GABA/kg.

Phytoestrogens for menopausal bone loss and climacteric symptoms

Women have always looked for non-hormonal options to alleviate menopausal vasomotor symptoms and prevent menopausal bone loss. The use of complementary and alternative medicine for these purposes has particularly increased after the publication of the Women's Health Initiative's results suggesting that there might be more risks than benefits with hormone replacement. Phytoestrogens are plant-derived estrogens that, although less potent than estradiol, bind to the estrogen receptor and can function as estrogen agonists or antagonists. Soy isoflavones extracted from soy are the phytoestrogens most commonly used by menopausal women. Because typical Western diets are low in phytoestrogens and taking into account the general difficulty in changing dietary habits, most clinical trials in Western women have used isoflavone-fortified foods or isoflavone tablets. Although some women might experience a reduction in the frequency or severity of hot flashes, most studies point towards the lack of effectiveness of isoflavones derived from soy or red clover, even in large doses, in the prevention of hot flashes and menopausal bone loss. This article is part of a Special Issue entitled 'Phytoestrogens'.

Phytoestrogens in the prevention of postmenopausal bone loss

Postmenopausal osteoporosis is a condition associated with low bone mass resulting from the increased bone resorption that occurs following a decline in estrogen levels. Phytoestrogens are plant-derived compounds that have affinity to the estrogen receptor and are able to act as either estrogen agonists or antagonists. Because of their structural similarity to 17-beta-estradiol, they have been studied extensively for their role in the prevention of postmenopausal bone loss. An extensive number of studies employing different types of isoflavone preparations (including soy foods, soy-enriched foods, and soy isoflavone tablets) have been conducted in a wide range of populations, including Western and Asian women. Although there is considerable variability in study design and duration, study population, type of soy isoflavone employed in the intervention, and study outcomes, the evidence points to a lack of a protective role of soy isoflavones in the prevention of postmenopausal bone loss.

The effects of soy isoflavone on bone density in north region of climacteric Chinese women

Only a few investigations were based on limb bone density. This study evaluated the efficacy of soy isoflavone in the treatment of the principal menopausal disorders, limb bone density and the role of pathway. The research protocol involved the random subdivision of the enrolled sample into two groups of 40 women, who were to receive treatment for 6 months with isoflavone (90 mg/day) and with placebo. All of the patients were asked to fill in a questionnaire concerning their complaints. BMD of the radius and tibia were measured using quantitative ultrasound. Bone metabolism indexes calcium, phosphorus and alkaline phosphatase (ALP) were examined regularly. Serum cytokines interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) examined by ELISA. The results of the score of Kupperman table showed that the isoflavone can lead to a significant reduction in some of the disorders. Compared with placebo, the tibia bone density in isoflavone group increased obviously against the base value before trail. Isoflavone led to a stronger descent of the concentration of ALP and a decrease of IL-6 and TNF-α level than placebo. For climacteric women, soy isoflavone in the dose of 90 mg/day could improve some menopausal syndromes and was effective on increasing limb bone density, which maybe had the relationship with the levels of IL-6, TNF-α and ALP in serum.

The positive effect of soybean protein hydrolysates-calcium complexes on bone mass of rapidly growing rats

It was previously found that soybean protein hydrolysates (SPHs) can bind with calcium to form soluble complexes and promote calcium uptake by Caco-2 cells. However, the role of SPHs-calcium complexes on bone mass still needs to be explored. Fast growing male and female rats (n = 72) were assigned to eight groups: Control, lactic acid calcium (LCa), SPHs-calcium complexes (SPHCa) and casein phosphopeptides calcium (CPPCa). After four weeks treatment, oral administration of SPHCa significantly increased femur BMD of rats compared with Control and LCa groups (P < 0.05), while there are no obvious difference on the BMD of femur and lumbar vertebrae between SPHCa and CPPCa groups. Also, SPHCa showed a tendency to improve the mechanical properties of vertebra lumber for female rats. These findings suggest that the SPHs-calcium complexes might have positive effects on bone accretion of fast growing animals. This study brings new insight for better understanding the role of soybean protein itself on bone mass.

Soy germ isoflavones improve menopausal symptoms but have no effect on blood lipids in early postmenopausal Chinese women: a randomized placebo-controlled trial

OBJECTIVE

Estrogen therapy is, to date, the most effective treatment of menopausal syndrome and also has a favorable effect on lipid profiles. Because of its potential adverse effects, however, a more acceptable alternative therapy needs to be identified. This study examines the effect of soy germ isoflavones on menopausal symptoms and serum lipids.

METHODS

Ninety early postmenopausal Chinese women, aged 45 to 60 years, were randomly assigned to three treatment groups (30 each) receiving daily doses of 0 (placebo), 84, and 126 mg of soy germ isoflavones. Hot flush frequency, Kupperman scores, serum 17β-estradiol, follicle-stimulating hormone, luteinizing hormone, and serum lipids, including triglyceride, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, apolipoprotein A-I, and apolipoprotein B100, were assessed at baseline and at 12 and 24 weeks after treatment.

RESULTS

Both the frequency of hot flushes and the Kupperman index score decreased in all three treatment groups during the intervention period, but the percentage decreases in both were significantly greater in the two isoflavone groups (44.3 ± 19.1 and 57.8 ± 37.4 [84 mg isoflavones]; 48.5 ± 27.2 and 56.7 ± 26.7 [126 mg isoflavones]) than in the placebo group (27.8 ± 15.5 and 34.6 ± 46.2; p < 0.01). There was no significant difference in the changes in estradiol, follicle-stimulating hormone, and luteinizing hormone among the three treatment groups during the study, and no significant differences were observed in the lipid components.

CONCLUSIONS

A daily supplement of 84 or 126 mg soy germ isoflavones may improve menopausal symptoms, although neither dose was found to affect lipid profiles in early postmenopausal Chinese women after 24 weeks of treatment. The favorable effects are unlikely to be associated with female hormones.

Bone mineral density in postmenopausal Chinese women treated with calcium fortification in soymilk and cow's milk

Eighteen months of daily consumption of milk containing 250 mg calcium prevented bone mineral density (BMD) loss at the hip and the femoral neck in postmenopausal Chinese women aged 45 to 65.

INTRODUCTION

Estrogen-related bone loss in postmenopausal women can be prevented by the consumption of milk with high doses of calcium and soymilk with high doses of isoflavones. However, high doses of calcium and isoflavones may not be necessary to attain a beneficial effect of milk and soymilk on BMD. We hypothesized that BMD will increase in postmenopausal Chinese women who consume daily 250 mg calcium in milk or soymilk. Milk prevented bone loss at the hip and the femoral neck in postmenopausal Chinese women.

METHODS

A total of 141 eligible Chinese women without osteoporosis, aged 45-65, and postmenopausal for more than 2 years were randomized into groups receiving for 18 months (A) milk with 250 mg calcium daily, (B) soymilk with 250 mg calcium daily, or (C) neither milk nor soymilk. Dual-energy X-ray absorptiometry measured the BMD of the spine and hip at 0, 6, 12, and 18 months.

RESULTS

The BMD in the hip (2.52%) and the femoral neck (2.82%) of the women consuming milk was significantly higher (hip, P = 0.01; femoral neck, P < 0.0000001). The women in the control group experienced a reduction in BMD at all sites; the reduction in BMD was only significant at the hip during 12 months (P = 0.008) and at the femoral neck during 18 months (P = 0.005).

CONCLUSIONS

Daily consumption of milk containing 250 mg calcium over 18 months prevents BMD loss at the hip and the femoral neck in postmenopausal Chinese women.

Systematic review of soy isoflavone supplements on osteoporosis in women

OBJECTIVE

To clarify the effect of soy isoflavones on prevention of osteoporosis, and the effective dosage of soy isoflavones and its duration.

METHODS

Random control trials that investigated the association of soy isoflavones and osteoporosis were included in the meta-analysis by researching MEDLINE, EMBASE and the Chinese Biomedical Database up to October 2011. The Rev Man software was used for all of the statistical analysis.

RESULTS

The present meta-analysis found that soy isoflavones significantly increased the bone mineral density by 54% and decreased the bone resorption marker urinary deoxypyridinoline (DPD) by 23% compared to baseline in women. Using random effects model, the effect of isoflavones on bone mineral density (BMD) regarding menopausal status and isoflavone dose revealed higher weighted mean difference changes were found in postmenopausal women and isoflavone dose above 75 mg/d. Subgroup analysis of trials with menopausal status, supplement type, isoflavone dose and intervention duration that used soy isoflavone extracts resulted in significant different overall effect of DPD using by random effects model. Sensitivity analysis indicated that the effect of soy isoflavones on BMD and DPD was robust.

CONCLUSIONS

The present meta-analysis reveals that soy isoflavone supplements significantly increase bone mineral density and decrease the bone resorption marker urinary DPD. It shows no significant effect on bone formation markers serum bone alkaline phosphatase. The significant effect of soy isoflavones on BMD and urinary DPD is relative to menopausal status, supplement type, isoflavone dose and intervention duration.

Prevention of bone resorption by intake of phytoestrogens in postmenopausal women: a meta-analysis

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.

Phytoestrogens and bone health

PURPOSE OF REVIEW

The present review summarizes the results of epidemiological studies and clinical trials assessing the skeletal effects of soy foods and soy dietary supplements.

RECENT FINDINGS

Results from epidemiological studies suggest a beneficial skeletal effect in Asian women consuming typical Asian diets, but clinical trials are conflictive regarding the effects of phytoestrogens on bone mineral density and bone turnover markers in premenopausal and postmenopausal women. Much of the controversy lies in differences in study design, reporting of results, participants' age and menopausal status, and type and dose of phytoestrogen used.

SUMMARY

Although western women will likely continue to incorporate soy foods and soy supplements into their diets with the increased availability of these products, published data are inconsistent and do not support soy's protective effect against bone loss. This conflicting evidence should be taken into account when considering using isoflavones in the prevention of bone loss and consequently fractures.

Effects of soy isoflavone supplements on bone turnover markers in menopausal women: systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Effects of soy isoflavone supplements on bone turnover markers remain unclear. This up-to-date systematic review and meta-analysis of randomized controlled trials (RCTs) was performed primarily to more completely and precisely clarify the effects on urinary deoxypyridinoline (DPD) and serum bone alkaline phosphatase (BAP) and secondarily to evaluate the effects on other bone turnover markers, compared with placebo in menopausal women.

METHODS

PubMed, CENTRAL, ICHUSHI, and CNKI were searched in June 2009 for relevant studies of RCTs. Data on study design, participants, interventions, and outcomes were extracted and methodological quality of each included trial was assessed.

RESULTS

From 3740 identified relevant articles, 10 (887 participants), 10 (1210 participants), and 8 (380 participants) RCTs were selected for meta-analysis of effects on DPD, BAP, and serum osteocalcin (OC), respectively, using Review Manager 5.0.22. Daily ingestion of an average 56 mg soy isoflavones (aglycone equivalents) for 10 weeks to 12 months significantly decreased DPD by 14.1% (95% CI: -26.8% to -1.5%; P=0.03) compared to baseline (heterogeneity: P<0.00001; I(2)=93%; random effects model). The overall effect of soy isoflavones on DPD compared with placebo was a significant decrease of -18.0% (95% CI: -28.4% to -7.7%, P=0.0007; heterogeneity: P=0.0001; I(2)=73%; random effects model). Subgroup analyses and meta-regressions revealed that isoflavone dose and intervention duration did not significantly relate to the variable effects on DPD. Daily supplementation of about 84 mg and 73 mg of soy isoflavones for up to 12 months insignificantly increased BAP by 8.0% (95% CI: -4.2% to 20.2%, P=0.20; heterogeneity: P<0.00001; I(2)=98%) and OC by 10.3% (95% CI: -3.1% to 23.7%, P=0.13; heterogeneity: P=0.002; I(2)=69%) compared with placebo (random effects model), respectively.

CONCLUSIONS

Soy isoflavone supplements moderately decreased the bone resorption marker DPD, but did not affect bone formation markers BAP and OC in menopausal women. The effects varied between studies, and further studies are needed to address factors relating to the observed effects of soy isoflavones on DPD and to verify effects on other bone turnover markers.

A randomized, double-blind, placebo-controlled, cross-over pilot study on the use of a standardized hop extract to alleviate menopausal discomforts

OBJECTIVES

To examine the efficacy of a hop extract (standardized at 100mug 8-prenylnaringenin per day) for relief of menopausal discomforts.

METHODS

A 16-week randomized, double-blind, placebo-controlled, cross-over study was conducted with 36 menopausal women. The participants were randomly allocated to either placebo or active treatment (hop extract) for a period of eight weeks after which treatments were switched for another eight weeks. The Kupperman Index (KI), the Menopause Rating Scale (MRS) and a multifactorial Visual Analogue Scale (VAS) were assessed at baseline, and after eight and sixteen weeks.

RESULTS

After 8 weeks, both active treatment and placebo significantly improved all outcome measures when compared to baseline with somewhat higher average reductions for placebo than for the active treatment. After 16 weeks only the active treatment after placebo further reduced all outcome measures, whereas placebo after active treatment resulted in an increase for all outcome measures. Although, the overall estimates of treatment efficacy (active treatment-placebo) based on linear mixed models do not show a significant effect, time-specific estimates of treatment efficacy indicate significant reductions for KI (P = 0.02) and VAS (P = 0.03) and a marginally significant reduction (P = 0.06) for MRS after 16 weeks.

CONCLUSIONS

Whereas the first treatment period resulted in similar reductions in menopausal discomforts in both treatment groups, results from the second treatment period suggest superiority of the standardized hop extract over placebo. Thus, phytoestrogen preparations containing this standardized hop extract may provide an interesting alternative to women seeking relief of mild vasomotor symptoms.

The soy isoflavones for reducing bone loss (SIRBL) study: a 3-y randomized controlled trial in postmenopausal women

BACKGROUND

Our previous study indicated that soy protein with isoflavones lessened lumbar spine bone loss in midlife women.

OBJECTIVE

We examined the efficacy of isoflavones (extracted from soy protein) on bone mineral density (BMD) in nonosteoporotic postmenopausal women. We hypothesized that isoflavone tablets would spare BMD, with biological (age, body weight, serum 25-hydroxyvitamin D) and lifestyle (physical activity, dietary intake) factors modulating BMD loss.

DESIGN

Our double-blind, randomized controlled trial (36 mo) included healthy postmenopausal women (aged 45.8-65.0 y) with intent-to-treat (n = 224) and compliant (n = 208) analyses. Treatment groups consisted of a placebo control group and 2 soy isoflavone groups (80 compared with 120 mg/d); women received 500 mg calcium and 600 IU vitamin D(3). Outcomes included lumbar spine, total proximal femur, femoral neck, and whole-body BMD.

RESULTS

Analysis of variance for intent-to-treat and compliant (> or =80%) models, respectively, showed no treatment effect for spine (P = 0.46, P = 0.21), femur (P = 0.86, P = 0.46), neck (P = 0.17, P = 0.14), or whole-body (P = 0.86, P = 0.78) BMD. From baseline to 36 mo, BMD declined regardless of treatment. In intent-to-treat and compliant models, respectively, BMD decreases were as follows: spine (-2.08%, -1.99%), femur (-1.43%, -1.38%), neck (-2.56%, -2.51%), and whole body (-1.66%, -1.62%). Regression analysis (compliant model) indicated that age, whole-body fat mass, and bone resorption were common predictors of BMD change. After adjustment for these factors, 120 mg (compared with placebo) was protective (P = 0.024) for neck BMD. We observed no treatment effect on adverse events, endometrial thickness, or bone markers.

CONCLUSION

Our results do not show a bone-sparing effect of extracted soy isoflavones, except for a modest effect at the femoral neck. This trial was registered at clinicaltrials.gov as NCT00043745.

Side effects of phytoestrogens: a meta-analysis of randomized trials

BACKGROUND

Phytoestrogens are widely used by postmenopausal women for the treatment of the climacteric syndrome. The risk of adverse effects of this treatment, however, is unknown.

METHODS

Using a fixed-effects model, we performed a meta-analysis of side effects comparing phytoestrogen treatment with placebo or no treatment in randomized controlled trials.

RESULTS

We identified 174 randomized controlled trials. Side effects were reported in 92/174 randomized controlled trials with 9629 participants. The overall incidence of side effects in the phytoestrogen and control groups was 2019/5502 (36.7%) and 1824/4806 (38.0%), respectively (P=.2; incidence rate ratio [IRR] 1.01; 95% confidence interval [CI], 0.95-1.08). Comparing various side effect categories, we found significantly higher rates of gastrointestinal side effects among phytoestrogen users (P=.003; IRR 1.28; 95% CI, 1.08-1.50). Gynecological (IRR 0.94; 95% CI, 0.74-1.20), musculoskeletal (IRR 1.20; 95% CI, 0.94-1.53), neurological (IRR 0.91; 95% CI, 0.70-1.19), and unspecific side effects (IRR 0.95; 95% CI, 0.88-1.03) were not significantly different between groups. Within side effect categories, we found no significantly higher rates of side effects in women using phytoestrogens. Specifically, the rates of hormone-related side effects such as endometrial hyperplasia, endometrial cancer, and breast cancer were not significantly different between groups.

CONCLUSIONS

Based on the available evidence, phytoestrogen supplements have a safe side-effect profile with moderately elevated rates of gastrointestinal side effects. Rates of vaginal bleeding, endometrial hyperplasia, endometrial cancer, and breast cancer were not significantly increased among phytoestrogen users in the investigated studies.

Effect of long-term intervention of soy isoflavones on bone mineral density in women: a meta-analysis of randomized controlled trials

INTRODUCTION

A number of RCTs have examined the role of soy isoflavones on bone mineral density (BMD) and yielded inconsistent results. This meta-analyses aims to assess the overall effect of soy isoflavones on BMD.

METHODS

We searched for all articles published in English from January 1990 to March, 2008. We included RCTs of soy isoflavone supplementation in women of at least one year duration. The main outcomes were BMD changes from baseline at the lumbar spine, total hip and femoral neck.

RESULTS

We identified 10 eligible RCTs containing 896 women. A mean dose of 87 mg soy isoflavones for at least one year did not significantly affect BMD changes. The mean (95%CI) differences in BMD changes (in mg/cm(2)/year) were 4.1 (-1.6, 9.8) (0.4%) at the lumbar spine, -1.5 (-7.2, 4.3) (-0.3%) at the femoral neck under random-effects model, and 2.5 (-0.5, 5.4) (0.2%) at the total hip by fix-effects model, respectively. Similar results were obtained in subgroup analyses by isoflavone sources (soy protein vs. isoflavone extract), ethnic differences (Asian vs. Western). Larger dose (>or=80 mg/d), but not lower dose (<80 mg/d), of isoflavone intervention tended to have a weak beneficial effect on spine BMD (p=0.08 vs. p=0.94).

CONCLUSIONS

Soy isoflavone supplementation is unlikely to have significant favorable on BMD at the lumbar spine and hip in women.

Phyto-oestrogens and bone health

As oestrogen deficiency is the main cause in the pathogenesis of osteoporosis hormone-replacement therapy remains the mainstay for prevention. However, prophylaxis by hormone-replacement therapy is limited. Phyto-oestrogens, which are weakly-oestrogenic compounds present in plants, deserve particular mention because emerging data support the suggestion that they may prevent bone loss associated with the menopause. In the past few years extensive research using animal models has provided convincing data to indicate a significant improvement in bone mass or other end points following feeding with soyabean. Moreover, observational studies relate the lower incidence of osteoporosis among women in the Eastern world to a diet rich in phyto-oestrogens. However, it is not valid to extrapolate to the Western situation. The varied clinical trials that have been published suggest that isoflavones reduce bone loss in women in the early period post menopause, but a definitive result requires more investigations of the effect of phyto-oestrogens on bone health that have substantial sample size and are of long duration. In addition, the clinical efficacy of soya foods in preventing osteopenia depends on their intestinal metabolism. Thus, phyto-oestrogens are a source for putative innovative dietary health intervention for post-menopausal women. However, more data are necessary, particularly in relation to their effect on the risk of fracture.