Decreased Bone Resorption with Soy Isoflavone Supplementation in Postmenopausal Women

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.

Effects of isoflavone and probiotic intake on calcium transport and bone metabolism biomarkers in female rats

Calcium is essential for maintaining bone health as it contributes to bone formation, remodeling, strength, and density. This study investigated the effect of isoflavones and probiotics on calcium transporters' gene expression, serum calcium levels, and bone metabolism biomarkers in healthy female rats. Forty-eight female Wistar rats were classified into six groups. Bone metabolism biomarkers (pyridinoline, deoxypyridinoline, parathyroid hormone, and osteocalcin) and serum calcium levels were measured by enzyme-linked immunosorbent assay (ELISA) and atomic absorption spectroscopy (AAS), respectively. Gene expression of calcium transporters (Trpv5 and Trpv6) was evaluated in duodenum and jejunum tissue samples using quantitative polymerase chain reaction (qPCR). Trpv5 and Trpv6, epithelial calcium channels, play a crucial role in calcium transport and homeostasis in the body. The study consisted of a1-week adaptation period for the rats to adjust to the controlled conditions, followed by an 8-week intervention phase. The daidzein and genistein group showed a significant increase in the gene expression of the Trpv6 transporter in the duodenum and a marked decrease in serum pyridinoline levels compared to the control group. The tempeh and soybean groups showed a significant decrease in the gene expression of the Trpv5 calcium transporter in the jejunum. However, no significant influence of the Lactobacillus acidophilus diet on calcium transport and bone metabolism biomarkers was observed in the L. acidophilus group. The correlation analysis showed a significant positive relationship between serum calcium, bone metabolism biomarkers, and calcium transporters. In conclusion, our study demonstrates that the daidzein and genistein diet improves calcium transport in the duodenum and reduces pyridinoline serum concentrations, while tempeh and soybean diets reduce calcium transport in the jejunum. However, the combination of daidzein, genistein, and L. acidophilus did not demonstrate a synergistic effect on calcium transport and bone metabolism, suggesting that further investigations are needed to elucidate their potential interactions.

Review of Isoflavones and Their Potential Clinical Impacts on Cardiovascular and Bone Metabolism Markers in Peritoneal Dialysis Patients

Cardiovascular disease is the most important cause of mortality in patients with chronic kidney disease, including patients undergoing peritoneal dialysis. Oxidative stress, systemic and vascular inflammation, and lipid abnormalities are important causes of cardiovascular disease in these patients. Bone disorders are also a common complication in dialysis patients and can lead to bone fractures, decreased quality of life, vascular calcification, cardiovascular disease, and increased mortality. Studies in non-uremic populations have shown that soy isoflavones have beneficial effects on oxidative stress, inflammation, lipid abnormalities, and markers of bone metabolism; however, very few studies in this field have been conducted with peritoneal dialysis patients. This paper reviews the key data regarding the effects of soy isoflavones on cardiovascular disease and bone markers and discusses the role of this nutraceutical in preventing and managing the complications of peritoneal dialysis.

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.

Bovine Milk Extracellular Vesicles Are Osteoprotective by Increasing Osteocyte Numbers and Targeting RANKL/OPG System in Experimental Models of Bone Loss

Studying effects of milk components on bone may have a clinical impact as milk is highly associated with bone maintenance, and clinical studies provided controversial associations with dairy consumption. We aimed to evaluate the impact of milk extracellular vesicles (mEVs) on the dynamics of bone loss in mice. MEVs are nanoparticles containing proteins, mRNA and microRNA, and were supplemented into the drinking water of mice, either receiving diet-induced obesity or ovariectomy (OVX). Mice receiving mEVs were protected from the bone loss caused by diet-induced obesity. In a more severe model of bone loss, OVX, higher osteoclast numbers in the femur were found, which were lowered by mEV treatment. Additionally, the osteoclastogenic potential of bone marrow-derived precursor cells was lowered in mEV-treated mice. The reduced stiffness in the femur of OVX mice was consequently reversed by mEV treatment, accompanied by improvement in the bone microarchitecture. In general, the RANKL/OPG ratio increased systemically and locally in both models and was rescued by mEV treatment. The number of osteocytes, as primary regulators of the RANKL/OPG system, raised in the femur of the OVX mEVs-treated group compared to OVX non-treated mice. Also, the osteocyte cell line treated with mEVs demonstrated a lowered RANKL/OPG ratio. Thus, mEVs showed systemic and local osteoprotective properties in two mouse models of bone loss reflected in reduced osteoclast presence. Data reveal mEV potential in bone modulation, acting via osteocyte enhancement and RANKL/OPG regulation. We suggest that mEVs could be a therapeutic candidate for the treatment of bone loss.

Effects of isoflavones on bone turnover markers in peritoneal dialysis patients: a randomized controlled trial

PURPOSE

The aim of this study was to investigate the effects of soy isoflavones on serum markers of bone formation and resorption in peritoneal dialysis (PD) patients.

METHODS

In this randomized, double-blind, placebo-controlled trial, 40 PD patients were randomly assigned to either the soy isoflavone or the placebo group. The patients in the soy isoflavone group received 100 mg soy isoflavones daily for 8 weeks, whereas the placebo group received corresponding placebos. At baseline and the end of the 8th week, 7 ml of blood was obtained from each patient after a 12- to 14-h fast and serum concentrations of bone formation markers (osteocalcin and bone alkaline phosphatase), bone resorption markers [N-telopeptide and receptor activator of nuclear factor kappa B ligand (RANKL)], and osteoprotegerin as an inhibitor of bone resorption were measured.

RESULTS

Serum N-telopeptide concentration decreased significantly up to 27% in the soy isoflavone group at the end of week 8 compared to baseline (P = 0.003). Also, serum RANKL concentration reduced significantly up to 17% in the soy isoflavone group at the end of week 8 compared to baseline (P = 0.03). These bone resorption markers did not significantly change in the placebo group during the study. There were no significant differences between the two groups in mean changes of serum osteocalcin, bone alkaline phosphatase, and osteoprotegerin.

CONCLUSION

This study indicates that daily administration of 100 mg soy isoflavone supplement to PD patients reduces serum N-telopeptide and RANKL which are two bone resorption markers. CLINICALTRIALS.GOV: NCT03773029, 2018.

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.

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.

Antiosteoporotic Activity of Genistein Aglycone in Postmenopausal Women: Evidence from a Post-Hoc Analysis of a Multicenter Randomized Controlled Trial

Genistein has a preventive role against bone mass loss during menopause. However, experimental data in animal models of osteoporosis suggest an anti-osteoporotic potential for this isoflavone. We performed a post-hoc analysis of a previously published trial investigating the effects of genistein in postmenopausal women with low bone mineral density. The parent study was a randomized, double-blind, placebo-controlled trial involving postmenopausal women with a femoral neck (FN) density <0.795 g/cm². A cohort of the enrolled women was, in fact, identified at the baseline as osteoporotic (n = 121) on the basis of their T-score and analyzed thereafter for the 24 months’ treatment with either 1000 mg of calcium and 800 IU vitamin D3 (placebo; n = 59); or calcium, vitamin D3, and Genistein aglycone (54 mg/day; genistein; n = 62). According to the femoral neck T-scores, 31.3% of the genistein and 30.9% of the placebo recipients were osteoporotic at baseline. In the placebo and genistein groups, the 10-year hip fracture probability risk assessed by Fracture Risk Assessment tool (FRAX) was 4.1 ± 1.9 (SD) and 4.2 ± 2.1 (SD), respectively. Mean bone mineral density (BMD) at the femoral neck increased from 0.62 g/cm² at baseline to 0.68 g/cm² at 1 year and 0.70 g/cm² at 2 years in genistein recipients, and decreased from 0.61 g/cm² at baseline to 0.60 g/cm² at 1 year and 0.57 g/cm² at 2 years in placebo recipients. At the end of the study only 18 postmenopausal women had osteoporosis in the genistein group with a prevalence of 12%, whereas in the placebo group the number of postmenopausal women with osteoporosis was unchanged, after 24 months. This post-hoc analysis is a proof-of concept study suggesting that genistein may be useful not only in postmenopausal osteopenia but also in osteoporosis. However, this proof-of concept study needs to be confirmed by a large, well designed, and appropriately focused randomized clinical trial in a population at high risk of fractures.

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.

Haematological and histopathological effects of apigenin, phloretin and myricetin based on uterotrophic assay in immature Wistar female albino rats

In this study, it is aimed to determine the histopathological and haematological effects of apigenin, phloretin and myricetin on Wistar immature female rats using Tier 2 of the uterotrophic assay. The female rats were divided into 17 groups with 6 rats in each group. There was a negative control group and positive control dose groups that contained 0.07 µg/kg/day, 0.7 µg/kg/day and 7 µg/kg/day of ethinyl estradiol (EE), 0.7 µg/kg/day 17α-ethinyl estradiol + 1 mg/kg/day tamoxifen and genistein. The other dose groups contain 1 mg/kg/day, 10 mg/kg/day and 100 mg/kg/day of apigenin, myricetin and phloretin. All chemicals had been given to Wistar immature female rats with oral gavage for three consecutive days. At the end of the study, blood samples were analysed for haematological parameters. Tissue samples that were taken from the liver, kidney, spleen and thyroid were histopathologically and histomorphometrically examined. There were no significant differences between oil control and other dose groups for glomerular histomorphometry. However, there were significant differences for thyroid histomorphometry. Especially, 10 and 100 mg/kg/day of phloretin dose groups had a significant increase in colloid surface area in thyroid compared with the 1 mg/kg/day of phloretin and oil control groups. Significant histopathological changes (congestion, degeneration, fibrosis and mononuclear cell infiltration) were noted in the tissue specimens obtained from the treatment groups compared with the control group. According to the results of the haematological analysis of the groups, especially the values of erythrocytes and haematocrit were increased significantly in most of the dose groups according to the oil control group.

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 and bone health at different reproductive stages

BACKGROUND

Isoflavones are an alternative to hormonal therapy for the relief of menopausal symptoms. Since isoflavones interact with estrogen receptors it has been hypothesized that such substances may have an effect on bone health.

OBJECTIVE

To clarify the effect of isoflavones on bone at experimental and clinical level, and to identify areas that require further clarification and research.

METHOD

A systematic review of studies involving isoflavones and bone health was performed, and a specific search on isoflavone's mechanism of action and the importance of equol production was made based on Internet search engines, MEDLINE (1966-October 2012) and the Cochrane Controlled Clinical Trials Register. This search was supplemented by a handsearch of reference lists of selected papers.

RESULTS

In vitro and animal studies show a positive effect of isoflavones on bone which has not been clearly confirmed by long-term human trials. Equol producers seem to present a more positive response to isoflavone intervention. Isoflavone rich diets could help maintain peak bone mass in premenopausal women. The effect of isoflavones in perimenopausal women is insufficiently studied but it seems to attenuate bone loss in the menopausal transition. In postmenopause, isoflavones may present a modest benefit but its clinical relevance in preventing osteoporotic fractures remains to be determined.

CONCLUSIONS

The present review suggests that isoflavone increase bone mineral density and decrease the bone turnover resorption markers. The effect of soy isoflavones on BMD is mediated by equol production, reproductive status, supplement type, isoflavone dose and intervention duration.

Effect of a combination of genistein, polyunsaturated fatty acids and vitamins D3 and K1 on bone mineral density in postmenopausal women: a randomized, placebo-controlled, double-blind pilot study

Purpose

Many postmenopausal women desire non-pharmaceutical alternatives to hormone therapy for protection against osteoporosis. Soybean isoflavones, especially genistein, are being studied for this purpose. This study examined the effects of synthetic genistein in combination with other potential bone-protective dietary molecules on bone mineral density (BMD) in early postmenopausal women.

Methods

In this 6-month double-blind pilot study, 70 subjects were randomized to receive daily either calcium only or the geniVida™ bone blend (GBB), which consisted of genistein (30 mg/days), vitamin D3 (800 IU/days), vitamin K1 (150 μg/days) and polyunsaturated fatty acids (1 g polyunsaturated fatty acids as ethyl ester: eicosapentaenoic acid/docosahexaenoic acid ratio = ~2/1). Markers of bone resorption and formation and BMD at the femoral neck, lumbar spine, Ward’s triangle, trochanter and intertrochanter, total hip and whole body were assessed.

Results

Subjects supplemented with the GBB (n = 30) maintained femoral neck BMD, whereas in the placebo group (n = 28), BMD significantly decreased (p = 0.007). There was also a significant difference (p < 0.05) in BMD between the groups at Ward’s triangle in favor of the GBB group. Bone-specific alkaline phosphatase and N-telopeptide significantly increased in the GBB group in comparison with those in baseline and in the placebo group. The GBB was well tolerated, and there were no significant differences in adverse events between groups.

Conclusions

The GBB may help to prevent osteoporosis and reduce fracture risk, at least at the hip, in postmenopausal women. Larger and longer-term clinical trials are warranted.

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.

Association between vitamin K intake from fermented soybeans, natto, and bone mineral density in elderly Japanese men: the Fujiwara-kyo Osteoporosis Risk in Men (FORMEN) study

SUMMARY

A cross-sectional analysis of 1,662 community dwelling elderly Japanese men suggested that habitual natto intake was significantly associated with higher bone mineral density (BMD). When adjustment was made for undercarboxylated osteocalcin levels, this association was insignificant, showing the natto-bone association to be primarily mediated by vitamin K.

INTRODUCTION

Low vitamin K intake is associated with an increased risk of hip fracture, but reports have been inconsistent on its effect on BMD. Our first aim was to examine the association between BMD and intake of fermented soybeans, natto, which contain vitamin K1 (20 μg/pack) and K2 (380 μg/pack). Our second aim was to examine the association between undercarboxylated osteocalcin (ucOC), a biomarker of vitamin K intake, and BMD to evaluate the role of vitamin K in this association.

METHODS

Of the Japanese men aged ≥65 years who participated in the baseline survey of the Fujiwara-kyo Osteoporosis Risk in Men study, 1,662 men without diseases or medications known to affect bone metabolism were examined for associations between self-reported natto intake or serum ucOC levels with lumbar spine or hip BMD.

RESULTS

The subjects with greater intake of natto showed significantly lower level of serum ucOC. Analysis after adjustment for confounding variables showed an association of greater intake of natto with both significantly higher BMD and lower risk of low BMD (T-score < -1 SD) at the total hip and femoral neck. This association became insignificant after further adjustment for ucOC level.

CONCLUSION

Habitual intake of natto was associated with a beneficial effect on bone health in elderly men, and this association is primarily due to vitamin K content of natto, although the lack of information on dietary nutrient intake, including vitamin K1 and K2, prevented us from further examining the association.

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.

Effects of soya isoflavones and exercise on body composition and clinical risk factors of cardiovascular diseases in overweight postmenopausal women: a 6-month double-blind controlled trial

Results from a pilot project indicate that isoflavones and exercise could have an additive effect on body composition and clinical risk factors of CVD in postmenopausal women. The objective of the present study was to assess the combined effect of exercise and isoflavones in overweight-to-obese postmenopausal women. In this double-blind randomised controlled trial, 100 overweight-to-obese (BMI 29·9 (sd 3·2) kg/m2) postmenopausal women were assigned to four groups: (1) placebo (PLA); (2) isoflavones (ISO); (3) exercise and placebo (Ex+PLA); (4) exercise and isoflavones (Ex+ISO). The supplementation contained 70 mg/d of isoflavones. Exercise consisted of three weekly sessions of resistance training and aerobics. Outcome measures included fat mass (FM), lean body mass (LBM), bone mineral density, lipid profile, fasting glucose, fasting insulin and insulin resistance (homeostasis assessment model). The main effects of exercise were observed for total FM (P = 0·02), FM% (P < 0·01), trunk FM% (P = 0·05), arm FM% (P < 0·01), leg FM% (P = 0·02), arm LBM (P < 0·01), leg LBM (P = 0·02) and C-reactive protein (P < 0·01). A main effect was detected for isoflavones in improving leg FM% (P = 0·05). No interactions were observed between isoflavones and exercise. In conclusion, it was observed that 6 months of exercise brought favourable changes in total FM, FM% and LBM in overweight postmenopausal women. No synergistic effects were observed between exercise and isoflavones. However, isoflavones could have a beneficial effect on leg FM%.

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.

Design and baseline characteristics of the soy phytoestrogens as replacement estrogen (SPARE) study--a clinical trial of the effects of soy isoflavones in menopausal women

Following the results of the Women's Health Initiative, many women now decline estrogen replacement at the time of menopause and seek natural remedies that would treat menopausal symptoms and prevent bone loss and other long-term consequences of estrogen deficiency, but without adverse effects on the breast, uterus, and cardiovascular system. The results of most soy studies in this population have had limitations because of poor design, small sample size, or short duration. This report describes the study rationale, design, and procedures of the Soy Phytoestrogens As Replacement Estrogen (SPARE) study, which was designed to determine the efficacy of soy isoflavones in preventing spinal bone loss and menopausal symptoms in the initial years of menopause. Women ages 45 to 60 without osteoporosis and within 5 years from menopause were randomized to receive soy isoflavones 200mg daily or placebo for 2 years. Participants have yearly measurements of spine and hip bone density, urinary phytoestrogens, and serum lipids, thyroid stimulating hormone, and estradiol. Menopausal symptoms, mood changes, depression, and quality of life are assessed annually. The SPARE study recruited 283 women, 66.1% were Hispanic white. With a large cohort, long duration, and large isoflavone dose, this trial will provide important, relevant, and currently unavailable information on the benefits of purified soy isoflavones in the prevention of bone loss and menopausal symptoms in the first 5 years of menopause. Given the high proportion of Hispanics participating in the study, the results of this trial will also be applicable to this minority group.

Simultaneous determination of 11 phytoestrogens in human serum using a 2 min liquid chromatography/tandem mass spectrometry method

A rapid 2 min liquid chromatography-tandem mass spectrometry (LC-MS/MS) method operating in multiple reaction ion monitoring mode was developed and validated that allows for the characterization and simultaneous quantification of 11 phytoestrogen metabolites with mass transitions m/z 241/119 (equol), 253/132 (daidzein), 255/149 (dihydrodaidzein), 257/108 (O-desmethylangolesin), 269/133 (genistein), 283/184 (glycitein), 267/191 (formononetin), 289/109 (biochanin A), 267/91 (coumestrol), enterodiol (301/253), and enterolactone (297/253). The method was demonstrated to be specific and sensitive, and a linear response for each phytoestrogen was observed over a range of 1-5000 ng/mL in human serum with the exception of dihydrodaidzein, whose lower limit of quantification was 2 ng/mL. The separation was carried out on a Synergi Polar-RP 2.5 micron (50 mm x 2.0 mm i.d.) column at 50 degrees C with water and acetonitrile (both containing 10 mM ammonium acetate) as the mobile phase under gradient conditions at a flow rate of 0.75 mL/min. This LC-MS/MS method is very useful for high-throughput analysis of phytoestrogens and proved to be simple, sensitive, reproducible, and reliable.

Flavonoids and age-related disease: risk, benefits and critical windows

Plant derived products are consumed by a large percentage of the population to prevent, delay and ameliorate disease burden; however, relatively little is known about the efficacy, safety and underlying mechanisms of these traditional health products, especially when taken in concert with pharmaceutical agents. The flavonoids are a group of plant metabolites that are common in the diet and appear to provide some health benefits. While flavonoids are primarily derived from soy, many are found in fruits, nuts and more exotic sources, e.g., kudzu. Perhaps the strongest evidence for the benefits of flavonoids in diseases of aging relates to their effect on components of the metabolic syndrome. Flavonoids from soy, grape seed, kudzu and other sources all lower arterial pressure in hypertensive animal models and in a limited number of tests in humans. They also decrease the plasma concentration of lipids and buffer plasma glucose. The underlying mechanisms appear to include antioxidant actions, central nervous system effects, gut transport alterations, fatty acid sequestration and processing, PPAR activation and increases in insulin sensitivity. In animal models of disease, dietary flavonoids also demonstrate a protective effect against cognitive decline, cancer and metabolic disease. However, research also indicates that the flavonoids can be detrimental in some settings and, therefore, are not universally safe. Thus, as the population ages, it is important to determine the impact of these agents on prevention/attenuation of disease, including optimal exposure (intake, timing/duration) and potential contraindications.

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.

Soy proteins and isoflavones affect bone mineral density in older women: a randomized controlled trial

BACKGROUND

Soy foods contain several components (isoflavones and amino acids) that potentially affect bone. Few long-term, large clinical trials of soy as a means of improving bone mineral density (BMD) in late postmenopausal women have been conducted.

OBJECTIVE

Our goal was to evaluate the long-term effect of dietary soy protein and/or soy isoflavone consumption on skeletal health in late postmenopausal women.

DESIGN

We conducted a randomized, double-blind, placebo-controlled clinical trial in 131 healthy ambulatory women aged >60 y. Ninety-seven women completed the trial. After a 1-mo baseline period, subjects were randomly assigned into 1 of 4 intervention groups: soy protein (18 g) + isoflavone tablets (105 mg isoflavone aglycone equivalents), soy protein + placebo tablets, control protein + isoflavone tablets, and control protein + placebo tablets.

RESULTS

Consumption of protein powder and isoflavone pills did not differ between groups, and compliance with the study powder and pills was 80-90%. No significant differences in BMD were observed between groups from baseline to 1 y after the intervention or in BMD change between equol and non-equol producers. However, there were significant negative correlations between total dietary protein (per kg) and markers of bone turnover (P < 0.05).

CONCLUSIONS

Because soy protein and isoflavones (either alone or together) did not affect BMD, they should not be considered as effective interventions for preserving skeletal health in older women. The negative correlation between dietary protein and bone turnover suggests that increasing protein intakes may suppress skeletal turnover. This trial was registered at ClinicalTrials.gov as NCT00668447.

Effect of beer drinking on ultrasound bone mass in women

OBJECTIVE

To study the effect of beer consumption on bone mass in a group of healthy women, by using phalangeal bone ultrasound to evaluate the amplitude-dependent speed of sound.

METHODS

This was a cross-sectional study of 1697 healthy women (mean age 48.4 y, body mass index (BMI) 19.0-32.0 kg/m(2)), recruited in a clinical convenience sample and screened for the existence of disease and/or medication that would affect calcium metabolism. Of this total, 710 were premenopausal, 176 were perimenopausal, and 811 were postmenopausal. The women recruited completed a questionnaire that contained detailed sections on current cigarette, alcohol, caffeine, and nutrient consumption. In terms of current alcohol intake, the subjects were classified as moderate drinkers, light drinkers, and nondrinkers. Drinkers were also analyzed according to the kind of alcohol consumed: wine or beer.

RESULTS

Quantitative bone ultrasound values were greater in the beer drinkers compared with the no beer and/or wine drinkers. Taking the amplitude-dependent speed of sound as a dependent variable, and age, BMI, gonadal status, intake of beer and wine, and number of cigarettes per day as independent variables, we found age (beta = -1.52), BMI (beta = -3.86), gonadal status (beta = -27.47), and beer intake (beta = 1.06) to be significant.

CONCLUSION

The greater bone density found in women beer drinkers might be a result of the phytoestrogen content of this alcoholic drink; this requires further investigation.

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.

Effects of soy protein and isoflavones on circulating hormone concentrations in pre- and post-menopausal women: a systematic review and meta-analysis

BACKGROUND

Hormonal effects of soy and isoflavones have been investigated in numerous trials with equivocal findings. We aimed to systematically assess the effects of soy and isoflavones on circulating estrogen and other hormones in pre- and post-menopausal women.

METHODS

The Cochrane Library, MEDLINE and EMBASE (plus reviews and experts) were searched to December 2007. Inclusion of randomized or residential crossover trials of soy or isoflavones for 4 or more weeks on estrogens, SHBG, FSH, LH, progesterone and thyroid hormones in women was assessed independently in duplicate. Six percent of papers assessed were included. Data concerning participants, interventions, outcomes, potential effect modifiers and trial quality characteristics were extracted independently in duplicate.

RESULTS

Forty-seven studies (11 of pre-, 35 of post- and 1 of perimenopausal women) were included. In premenopausal women, meta-analysis suggested that soy or isoflavone consumption did not affect primary outcomes estradiol, estrone or SHBG concentrations, but significantly reduced secondary outcomes FSH and LH [by ∼20% using standardized mean difference (SMD), P = 0.01 and 0.05, respectively]. Menstrual cycle length was increased by 1.05 days (95% CI 0.13, 1.97, 10 studies). In post-menopausal women, there were no statistically significant effects on estradiol, estrone, SHBG, FSH or LH, although there was a small statistically non-significant increase in total estradiol with soy or isoflavones (∼14%, SMD, P = 0.07, 21 studies).

CONCLUSIONS

Isoflavone-rich soy products decrease FSH and LH in premenopausal women and may increase estradiol in post-menopausal women. The clinical implications of these modest hormonal changes remain to be determined.

Soy phytoestrogens: impact on postmenopausal bone loss and mechanisms of action

Due to their ability to mimic the actions of mammalian estrogens, soy phytoestrogens have been proposed as potential therapeutic agents to aid in preventing postmenopausal bone loss. In vitro, phytoestrogens promote osteoblastogenesis and inhibit osteoclastogenesis. Although a relatively large number of intervention studies have been undertaken in animals and humans, the efficacy of phytoestrogens as bone-protective agents in vivo remains unclear. Differences in the bioactivities of individual phytoestrogens, differences in phytoestrogen metabolism and bioavailability within different study populations, and imprecise reporting of the dose of phytoestrogens administered in intervention studies may have contributed to the disparity in study findings.

Soy isoflavones in the management of postmenopausal osteoporosis

This is a review article designed to address the effects of soy isoflavones on bone metabolism in postmenopausal women and their place in the prevention and treatment of postmenopausal osteoporosis. Soy isoflavones are natural products that could be used as an alternative to menopausal hormone therapy because they are structurally and functionally related to 17beta-estradiol. In vitro and animal studies have shown that they act in multiple ways to exert their bone-supporting effects. They act on both osteoblasts and osteoclasts through genomic and nongenomic pathways. Epidemiological studies and clinical trials suggest that soy isoflavones have beneficial effects on bone mineral density, bone turnover markers, and bone mechanical strength in postmenopausal women. However, there are conflicting results related to differences in study design, estrogen status of the body, metabolism of isoflavones among individuals, and other dietary factors. The long-term safety of soy isoflavone supplements remains to be demonstrated.

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.

Soy isoflavone intake increases bone mineral density in the spine of menopausal women: meta-analysis of randomized controlled trials

BACKGROUND & AIMS

The effects of isoflavones on bone loss appear inconsistent in randomized controlled trials. Therefore, we used a statistical method of combining these diverse data to clarify the effects of soy isoflavone intake on spine bone loss.

METHODS

We identified randomized controlled trials related to the effects of soy isoflavone intake on spine bone mineral density or spine bone mineral content and performed meta-analysis with Review Manager 4.2 software.

RESULTS

Ten studies with a total of 608 subjects were selected for meta-analysis. The spine bone mineral density in subjects who consumed isoflavones increased significantly by 20.6 mg/cm(2) (95% confidence interval: 4.5-36.6 mg/cm(2)) in comparison to that in subjects who did not consume isoflavones. Isoflavone intake vs placebo intake increased spine bone mineral content by 0.93 g (95% confidence interval: -0.37 to 2.24 g) with borderline significance. Increases in the spine bone mineral density with isoflavone intake of more than 90 mg/day and with treatment lasting 6 months were 28.5mg/cm(2) (95% confidence interval: 8.4-48.6 mg/cm(2)) and 27 mg/cm(2) (95% confidence interval: 8.3-45.8 mg/cm(2)), respectively.

CONCLUSIONS

Isoflavone intervention significantly attenuates bone loss of the spine in menopausal women. These favorable effects become more significant when more than 90 mg/day of isoflavones are consumed. And soy isoflavone consumption for 6 months can be enough to exert beneficial effects on bone in menopausal women.

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

OBJECTIVE

To clarify the effects of isoflavone intake on bone resorption and bone formation.

METHODS

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).

RESULTS

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.

CONCLUSIONS

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.

Flaxseed and soy protein isolate, alone and in combination, differ in their effect on bone mass, biomechanical strength, and uterus in ovariectomized nude mice with MCF-7 human breast tumor xenografts

In our previous study, flaxseed (FS) reduced while soy protein isolate (SPI) stimulated MCF-7 breast tumor growth in ovariectomized mice. In addition, combining SPI and FS resulted in a negation of SPI-induced tumor growth. In this study, the effects of SPI, FS, and their combination were further examined on mouse bone and uterus to further ensure overall safety of the breast cancer treatments. Ovariectomized mice with established MCF-7 xenografts were fed either a basal diet (control), or a basal diet supplemented with 10% FS, 20% SPI, or SPI + FS for 25 wk. Mouse bones were analyzed for mineral and biomechanical strength properties, and uterus weight was measured. The SPI group had a higher femur bone mineral density and biomechanical strength parameters (yield load, stiffness, and peak load) compared to control, while the FS group significantly increased femur stiffness and peak load. The SPI + FS group did not affect femur mineral, but significantly reduced whole femur area and length and increased femur yield load, stiffness, and peak load. Uterus weight was significantly increased by the SPI + FS group, while SPI alone induced an intermediate effect. In conclusion, all dietary treatments induced beneficial effects on bone in a preclinical mouse model of postmenopausal breast cancer. Although the SPI + FS and SPI groups exerted stimulatory effects on uterus weight, other histological parameters need to be measured to determine the overall safety of these breast cancer treatments on the uterus.

The Interleukin-6 inflammation pathway from cholesterol to aging--role of statins, bisphosphonates and plant polyphenols in aging and age-related diseases

We describe the inflammation pathway from Cholesterol to Aging. Interleukin 6 mediated inflammation is implicated in age-related disorders including Atherosclerosis, Peripheral Vascular Disease, Coronary Artery Disease, Osteoporosis, Type 2 Diabetes, Dementia and Alzheimer's disease and some forms of Arthritis and Cancer. Statins and Bisphosphonates inhibit Interleukin 6 mediated inflammation indirectly through regulation of endogenous cholesterol synthesis and isoprenoid depletion. Polyphenolic compounds found in plants, fruits and vegetables inhibit Interleukin 6 mediated inflammation by direct inhibition of the signal transduction pathway. Therapeutic targets for the control of all the above diseases should include inhibition of Interleukin-6 mediated inflammation.

Differential biliary excretion of genistein metabolites following intraduodenal and intravenous infusion of genistin in female rats

The purpose of this study was to determine whether bioflavonoid glucoside O-conjugates are absorbed from the intestine in the intact form or as their aglycones following hydrolysis by intestinal beta-glucosidases. In this study, the intestinal absorption of genistin, the beta-glucoside of the isoflavone genistein, was examined in anesthetized, adult female rats fitted with indwelling biliary cannulas. To first establish whether genistein, once absorbed, was converted into unique metabolites, genistin was infused into the femoral or portal veins and bile samples quantitatively collected. Analysis of bile samples by HPLC-mass spectrometry revealed that almost full recovery of the genistein component occurred in the form of unreacted genistin ( approximately 20%) and genistein 7beta-O-glucuronide ( approximately 80%). However, when genistin was infused into the upper small intestine, only genistein 7beta-O-glucuronide and the aglycone genistein appeared in the bile. There was no evidence for any biliary secretion of the unreacted genistin, thereby excluding its uptake in the intact form from the small intestine in this animal model.

Soy and red clover for mid-life and aging

INTRODUCTION

Menopause is associated with mid-life, a time when many women begin to experience the signs and symptoms of aging, such as increases in blood pressure, changes in lipid profiles, loss of bone mass density, and diminished memory and cognition. Given the result of the Women's Health Initiative, many women no longer consider hormone therapy the first option for promoting healthy aging. Instead, they are turning to botanical and dietary supplement (BDS) products in place of hormone therapy. This paper reviews the evidence available for use of isoflavones from soy and red clover for the treatment or prevention of these health issues.

METHODS

The MEDLINE and EMBASE databases were searched for articles relating to soy or red clover supplement use for prevention and/or treatment of heart disease, hyperlipidemia, osteoporosis, mood disorders and cognitive abilities. Studies were included if they were randomized, controlled trials and included peri- or postmenopausal women.

RESULTS

Isoflavone products appear to be the most useful for improving lipid profiles; however, the evidence suggests that isoflavone extracts from soy are less effective than products containing soy protein or red clover isoflavones. Soy protein appears to reduce levels of total cholesterol and low density lipoprotein cholesterol, while red clover reduces levels of triglycerides and increases high density lipoprotein cholesterol. The data were somewhat less convincing, although promising, for increasing bone mass density and improving cognitive abilities.

CONCLUSIONS

Research suggests that isoflavones found in soy foods and red clover appear to have a small but positive health effect on plasma lipid concentrations, bone mass density, and cognitive abilities. Given the lack of serious safety concerns in the short term, it would appear that including soy and red clover in the diet of postmenopausal women, not withstanding a soy allergy, might be beneficial.

Detection of isoflavones in mouse tibia after feeding daidzein

Many studies suggest that diets rich in isoflavones protect against bone loss or slow the loss of bone mass that occurs because of estrogen withdrawal. Although in vitro studies have reported effects of isoflavones on bone cells, the presence of daidzein and/or equol in bone tissue in vivo has not been reported. The objective of this study was to determine if daidzein and equol were present in bone tissue (tibias) after feeding mice a diet containing purified daidzein. Sham mice (n = 9) received control diet, and ovariectomized mice were randomized to control diet (Ovx) (n = 9) or control diet containing 200 mg of daidzein/kg of diet (n = 8) for 12 weeks. At necropsy, tibias and serum were collected. Mice in the Daidzein group had significantly higher (P < .05) levels of both daidzein and equol in tibias than Sham and Ovx mice. Tibia levels of daidzein and equol were approximately five and four times higher, respectively, than the Sham and Ovx groups. Similarly, mice fed daidzein also had significantly higher (P < .05) serum daidzein and equol than the Sham and Ovx mice. In conclusion, feeding a level of daidzein that is attainable by dietary intervention alone results in a high level of both daidzein and equol in tibias. These findings suggest that daidzein and its metabolite, equol, have the potential to act directly on bone cells in vivo.

Soy protein and bone mineral density in older men and women: A randomized trial

OBJECTIVE

Test the hypothesis that soy isoflavone supplementation preserves bone mineral density (BMD) in men and women.

METHODS

We conducted a controlled, parallel-arm, double-blinded trial with 145 participants, 50-80 years, with random assignment to soy beverage daily for 12 months. Active treatment (+ISO) received soy protein containing 83 mg isoflavones (45.6 mg genistein, 31.7 mg daidzein), aglycone units; the comparison group (-ISO) received soy protein containing 3mg isoflavones. We measured BMD using dual-energy X-ray absorptiometry at the total hip and posterior-anterior spine (L1-L4) at baseline in 22 women and 123 men, and at 12 months in 13 women and 98 men. We used linear mixed models to test for an isoflavone effect on percentage BMD change from baseline in spine and hip.

RESULTS

Among all participants, mean percent change in spine BMD (+/-S.E.) was 0.16+/-0.44 in -ISO (P=0.10) at 12 months. Treatment effects on spine BMD were significantly greater in women than men (P=0.01). At 12 months, in women, mean percent change was 0.58+/-0.70 in +ISO and -1.84+/-0.86 in -ISO (P=0.05); among men it was 1.32+/-0.53 in +ISO and 0.31+/-0.48 in -ISO (P=0.16). By comparison, percent change in hip BMD was similar in the treatment groups, and was not different between men and women. Mean percent change in hip BMD from baseline to 12 months was 0.54+/-0.38 in +ISO and -0.13+/-0.36 in -ISO (P=0.20) among all participants.

CONCLUSIONS

Soy protein containing isoflavones showed a modest benefit in preserving spine, but not hip BMD in older women.

Antimalarial drugs - host targets (re)visited

Every year, forty percent of the world population is at risk of contracting malaria. Hopes for the erradication of this disease during the 20th century were dashed by the ability of Plasmodium falciparum, its most deadly causative agent, to develop resistance to available drugs. Efforts to produce an effective vaccine have so far been unsuccessful, enhancing the need to develop novel antimalarial drugs. In this review, we summarize our knowledge concerning existing antimalarials, mechanisms of drug-resistance development, the use of drug combination strategies and the quest for novel anti-plasmodial compounds. We emphasize the potential role of host genes and molecules as novel targets for newly developed drugs. Recent results from our laboratory have shown Hepatocyte Growth Factor/MET signaling to be essential for the establishment of infection in hepatocytes. We discuss the potential use of this pathway in the prophylaxis of malaria infection.

One-year soy isoflavone supplementation prevents early postmenopausal bone loss but without a dose-dependent effect

It is believed that soy isoflavone has much potential effectiveness on the postmenopausal status; however, the optimal dose for preventing postmenopausal bone loss still remains unclear. This open-labeled, self-controlled pilot study was undertaken to determine the effect of 1-year supplementation of different high dosages of soy isoflavone in postmenopausal Taiwanese women. Forty-three women aged 45-67 years were enrolled and randomly assigned into a control (C), 100 mg/day isoflavone (IF100) and 200 mg/day isoflavone (IF200) groups for 1 year. Dual-energy X-ray absorptiometry and other related biochemical markers of bone metabolism were measured. Results indicated that the decrease in bone mineral density (BMD) was significant for lumbar vertebrae L1-3, L1-4 and the femur neck in the C group; surprisingly, the BMD of L1-3 was significantly elevated in the IF100 group; however, there were no consistent responses in the IF200 group. No significant change except loss of the bone mineral content of Ward's triangle (P=.003) was found in the IF200 group after treatment. The percentage change at L1-3 was less (P=.04) in the IF200 group when compared to the IF100 group. A relatively uniform direction of bone formation in expanding the weight and area with different rates of change resulted in different BMD changes. Both indicated a change of bone formation patterns with the higher-dose supplement. A protective effect of IF100 on estrogen-related bone loss was observed. A lack of a benefit such as high safety in the IF200 group for 1-year administration was ensured and lacked undesirable side effects.

Genistein alone and in combination with the mammalian lignans enterolactone and enterodiol induce estrogenic effects on bone and uterus in a postmenopausal breast cancer mouse model

The use of phytoestrogens, such as isoflavones and lignans, for treatment of postmenopausal breast cancer is increasing, but their effects on bone and other major organs are not clear. While the isoflavone genistein (GEN) has been shown to prevent or slow the loss of bone mineral density (BMD), the effect of lignans enterodiol (END) and enterolactone (ENL) are unknown. In this study, we determined in ovariectomized mice with human MCF-7 breast tumor xenografts the effects of the lignans, and GEN, alone and in combination, on bone and uterus. Mice with established MCF-7 tumors were fed a basal diet (AIN-93G), divided into 5 groups, and given daily subcutaneous injections (10 mg/kg body weight) of either ENL, END, GEN, a mixture of these compounds (MIX), or vehicle as a negative control for 22 weeks. Results showed that GEN acts estrogenically in both the uterus and bone by increasing the uterus weight, femur BMD, and femur biomechanical strength (yield load), while the lignans do not. However, treatment with MIX induced minimal effects on femur biomechanical strength parameters but significantly increased uterus weight. A significant positive correlation was observed between MCF-7 tumor volume and femur BMD and biomechanical strength parameters (femur peak load and yield load) but not with uterus weight, suggesting that the uterus may respond differently to phytoestrogens compared to MCF-7 tumors and bone. It is concluded that GEN induces beneficial effects on bone but has adverse effects on tumors and uterus in this model of postmenopausal breast cancer. The lignans do not exert adverse effects on any tissue, however, when combined with GEN, they exert an adverse effect on the uterus.