Benefits of soy germ isoflavones in postmenopausal women with contraindication for conventional hormone replacement therapy

Effect of Soy Isoflavones on Measures of Estrogenicity: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Despite recommendations to increase plant food consumption for public and planetary health and the role that soy foods can play in plant-predominant diets, controversies around the effects of soy foods, especially soy isoflavones, are a barrier to their intake. Given their cardioprotective effects and ability to alleviate menopausal symptoms, addressing these concerns is particularly relevant to women. This systematic review and meta-analysis of randomized controlled trials aimed to determine the effect of soy isoflavones on measures of estrogenicity in postmenopausal women. MEDLINE, Embase, and Cochrane Library were searched through August 2024 for randomized trials ≥3-mo investigating soy isoflavones compared with non-isoflavone controls in postmenopausal women. Outcomes included endometrial thickness (ET), vaginal maturation index (VMI), follicle-stimulating hormone (FSH), and estradiol. Independent authors extracted data and assessed risk of bias. Grading of Recommendations, Assessment, Development and Evaluation was used to assess certainty of evidence. We included 40 trials (52 trial comparisons, n = 3285) assessing the effect of a median reported dose of 75 mg/d of soy isoflavones in substitution for non-isoflavone controls over a median of 24 wk. Soy isoflavones had no statistically significant effect on any measure of estrogenicity; ET [mean difference, -0.22 mm (95% confidence interval, -0.45, 0.01 mm), PMD = 0.059], VMI [2.31 (-2.14, 6.75), PMD = 0.310], FSH [-0.02 IU/L (-2.39, 2.35 IU/L), PMD = 0.987], and estradiol [1.61 pmol/L (-1.17, 4.38 pmol/L), PMD = 0.256]. The certainty of evidence was high to moderate for all outcomes. Current evidence suggests that soy isoflavones do not exhibit estrogenic effects compared with non-isoflavone controls on 4 measures of estrogenicity in postmenopausal women. This synthesis supports that soy isoflavones likely act as selective estrogen receptor modulators, differing clinically from the hormone estrogen. Addressing public health concerns may promote soy foods as high-quality plant protein sources with low environmental impact and cost, particularly benefiting postmenopausal women and aligning with sustainable dietary patterns and guidelines. This study was registered in PROSPERO as CRD42023439239.

Efficacy of plant-derived dietary supplements in improving overall menopausal symptoms in women: An updated systematic review and meta-analysis

This updated systematic review and meta-analysis aims to confirm the effectiveness of plant-based supplements in improving overall menopausal symptoms and vasomotor symptoms. A systematic review of the literature was conducted by searching the PubMed/MEDLINE, Web of Science, EMBASE, and CENTRAL databases up to June 2022. Randomized placebo-controlled clinical trials that evaluated the effects of dietary supplements on menopausal symptoms were included. Outcome measures included daily hot flash frequency, Kupperman's index, Menopause Rating Scale, and Greene Climacteric Scale. Pooled data were analyzed using a fixed-effects model and expressed as a weighted mean difference with a 95% confidence interval for continuous outcomes. For qualitative assessment, 67 studies were selected. For quantitative assessment, 54 reports were obtained from 61 studies. The study participants were peri- or postmenopausal women aged 38-85, most of whom experienced hot flashes as a menopausal symptom. The investigational products included 28 soy-derived, 6 red clover-derived, and 28 other plant-derived supplements. Qualitative assessment revealed that approximately 76% of the studies were generally of fair or good quality, whereas 24% were of low quality. Meta-analysis results indicated significant improvements in all questionnaire scores, including hot flash frequency, in the dietary supplement group compared with the placebo group. Comprehensive evaluation using different questionnaire tools showed that the various plant-derived dietary supplements can significantly alleviate menopausal symptoms. However, further rigorous studies are needed to determine the association of plant-derived dietary supplements with menopausal health because of the general suboptimal quality and heterogeneous nature of current evidence.

Meal-Based Intervention on Health Promotion in Middle-Aged Women: A Pilot Study

Middle-aged women belong to a risk group for metabolic dysregulation and menopausal symptoms, mainly due to a dramatic hormonal shift. Supplementation with functional compounds or a single nutrient has been dominantly explored as a nutritional approach for improving aging-related health parameters. However, a meal-based approach might be another strategy for promoting the overall health of the target population. This pilot study aimed to develop a meal-based intervention for middle-aged women and to evaluate its potential health benefits. Considering the nutrient intake status of Korean middle-aged women, diets enriched with four major nutrients (isoflavone, omega-3, fiber, and calcium) were designed and provided to forty-nine women aged 50 to 65 with mild levels of menopausal symptoms for 8 weeks. In the post-intervention phase, they showed reduced body weight and body fat, and improved biochemical metabolic parameters with decreased levels of cholesterol, low-density lipoprotein-cholesterol, ApoB, and fasting insulin. Moreover, bone resorption markers and menopause symptoms were lower in the post-intervention phase. In conclusion, the meal-based intervention might be a prominent strategy for overall health promotion in relatively healthy middle-aged women and further investigation is needed to test its efficacy with a randomized controlled study.

The evaluation of sea cucumber (Acaudina leucoprocta) peptide on sex hormone regulation in normal and premature ovarian failure female mice

Sea cucumber peptides (SCPs) have various functional activities. However, studies to evaluate the efficacy and safety of SCPs from the perspective of sex hormones are still lacking. In this study, normal and premature ovarian failure (POF) female mice were used to assess the effect of SCPs on the sex hormones. The ovarian and uterine indices were not influenced by SCP both in normal and POF mice. In normal mice, SCP showed no significant impact on the estrous cycle, ovarian, uterine morphology, sex hormone levels, and sex hormone synthesis-related genes of the ovary. However, 0.6 mg per g bw dosage of SCP (SCPH) statistically increased mapk1 expression on normal mice hypothalamus. In POF mice, SCPH played a more positive role than a low dosage of SCP (0.2 mg per g bw). SCP ameliorated POF-induced estrous cycle disturbances and significantly increased serum estradiol, testosterone, and AMH levels. Moreover, SCP increased the synthesis of the sex hormone by upregulating the expression of StAR, Fshr, and Cyp19a1 in the ovary, which might be due to the activation of the cAMP-related signaling pathways. The upregulation of mapk1, Esr1, and Gnrh was also observed in the hypothalamus. Together, SCP is safe for normal female mice and seems to have positive effects on POF mice from sex hormone regulation. However, the risk of excessive supplementation of sex hormones induced by the SCP intake in POF mice needs to be further explored.

Long-term effects of a combination of isoflavones, agnus castus and magnolia extracts on climacteric symptoms and cardiometabolic risk profile in postmenopausal women

OBJECTIVE

To evaluate the long-term effects of a combination of isoflavones, agnus castus and magnolia extracts (combined isoflavone compound [CIC]) on climacteric symptoms and cardiometabolic risk in symptomatic postmenopausal women.

METHODS

This interventional, prospective study evaluated climacteric symptoms, mood and sleep disorders using the 21-item Greene Climacteric Scale (GCS) and 7-item Insomnia Severity Index (ISI) questionnaires; and cardiovascular, metabolic and thrombotic risk markers at baseline (T0) and after 12 months of CIC treatment (T1).

RESULTS

In healthy postmenopausal women (N = 71), 12-month CIC treatment significantly reduced patient-reported vasomotor symptoms (100% vs. 17%), mood disorders (67% vs. 25%) and sleep disorders (89% vs. 19%%) (all p < .001) compared with baseline; and significantly improved GCS psychological, somatic, and vasomotor domain scores and ISI sleep disturbance scores (all p < .05). CIC significantly reduced systolic (p = .022) and diastolic blood pressure (p < .001), and heart rate (p < .001); glucose concentrations (p = .018), HOMA index (p = .013), and ALT (p = .035), homocysteine (p = .005) and NT-proBNP (p = .003) levels.

CONCLUSIONS

Long-term CIC therapy improved vasomotor symptoms, mood disorders, sleep disorders, hemodynamic measurements and cardiometabolic risk markers in healthy postmenopausal women.

CLINICALTRIALS.GOV IDENTIFIER

NCT03699150.

The effects of isolated soy protein, isolated soy isoflavones and soy protein containing isoflavones on serum lipids in postmenopausal women: A systematic review and meta-analysis

Background: Many randomized controlled trials (RCTs) have assessed the effects of soy products on serum lipids. However, the responsible soy components and the magnitude of effects in healthy or hypercholesterolemic postmenopausal women are unclear. This review assessed the quality of these RCTs and estimated the effects of isolated soy protein, isolated soy isoflavones and soy protein containing isoflavones on total cholesterol (TC), LDL-C, HDL-C, triglycerides (TG), Apolipoprotein (Apo) A-1 and Apo B among postmenopausal women.Design: Forty-six eligible randomized controlled trials published up to 20 May 2019 were identified from the PubMed, Web of Science and Scopus databases. Weighted mean effect sizes were calculated for net changes in serum lipid concentrations by using random-effect models. Specific subgroup analyses were performed to identify the effect of covariates on serum lipid changes.Results: Soy consumption was associated with significant decrease in TG (mean differences (MD): -5.04 mg/dl; 95% CI: -9.95, -0.13; P = 0.044), TC (MD: -3.02 mg/dl; 95% CI: -5.56, -0.47; P = 0.02), LDL-C (MD: -3.27 mg/dl; 95% CI: -6.01, -0.53; P = 0.019) and HDL-C (MD: -2.28 mg/dl; 95% CI: -4.27, -0.29; P = 0.025). The reduction in LDL-C, TG and HDL were larger in subjects consuming isolated soy protein than isolated soy isoflavones. There was a significant decrease in serum TG and HDL levels with dosages of >25 grams per day soy protein rather than lower dosages of soy protein. The reductions in Apo A-1 were significantly larger in hypercholesterolemic subjects than in healthy subjects.Conclusions: Isolated soy protein significantly reduced serum TG, TC, LDL-C, HDL-C and Apo-B levels in postmenopausal women. Isolated soy isoflavones had a significant lowering effect on serum TC and Apo B levels. Soy protein containing isoflavones significantly reduced TG, TC, LDL-C and Apo B levels. Therefore, hyperlipidemia risk reduction with soy products is not uniform and strongly depends on the protein and isoflavone content of soy products, duration and dosage of consumption.

Complementary and Alternative Medicine for Menopause

Menopause is associated with problematic symptoms, including hot flashes, sleep problems, mood disorders, sexual dysfunction, weight gain, and declines in cognitive functioning. Many women seek complementary and alternative medicine (CAM) for symptom management. This article critically reviews the existing literature on CAM treatments most commonly used for menopausal symptoms. Electronic searches were conducted to identify relevant, English-language literature published through March 2017. Results indicate that mind and body practices may be of benefit in reducing stress and bothersomeness of some menopausal symptoms. In particular, hypnosis is a mind-body intervention that has consistently shown to have a clinically significant effect on reducing hot flashes. Evidence is mixed in regard to the efficacy of natural products and there are some safety concerns. Health care providers should consider the evidence on CAM in providing an integrative health approach to menopausal symptom management.

Soy germ extract alleviates menopausal hot flushes: placebo-controlled double-blind trial

BACKGROUND/OBJECTIVES

A double-blind, placebo-controlled study was performed to assess the potency of a soy germ preparation for the alleviation of menopausal hot flushes.

SUBJECTS/METHODS

Caucasian women with at least seven hot flushes daily were treated with soy germ extract (100 mg isoflavone glycosides) daily or with placebo for 12 weeks, followed by 12 weeks of open treatment with soy. Outcome parameters were the number of hot flushes and the evaluation of the Greene Climacteric Scale.

RESULTS

A total of 192 women were included. As the hot flush diaries from one study centre were lost, the assessment of hot flushes was based on 136 participants (soy: 54 women; placebo: 82 women). After 12 weeks, 180 women were available for the analysis of Greene Scale and safety (soy and placebo: each 90 women). Hot flushes were reduced by 43.3% (-3.5 hot flushes) with soy and by 30.8% with placebo (-2.6; p < 0.001). After the open treatment phase with soy, both original groups showed a reduction of 68% of hot flushes. A subgroup analysis showed better effects for soy when symptoms were classified as "severe" at baseline. After 12 weeks of double-blind treatment, there was an improvement from baseline values of 71 and 78% with soy with the items "hot flushes" and "sweating", compared with 24% for both items with placebo. Hormonal safety parameters remained uninfluenced.

CONCLUSIONS

Soy germ extract with 100 mg of isoflavone glycosides was shown to modestly, but significantly reduce menopausal hot flushes.

Effect of soy isoflavones supplement on climacteric symptoms, bone biomarkers, and quality of life in Korean postmenopausal women: a randomized clinical trial

BACKGROUND/OBJECTIVES

Soy isoflavones are expected to improve menopausal symptoms and osteoporosis in women. However, their efficacy is still inconclusive, and there was limited data for postmenopausal women in South Korea. We examined the effects of soy isoflavones on climacteric symptoms, bone biomarkers, and quality of life in Korean postmenopausal women.

SUBJECTS/METHODS

A randomized, double-blind study design was used. Eighty-seven participants who had undergone natural menopause were randomly administered either 70 mg/day isoflavones (n = 43) or placebo (n = 41) for 12 weeks. We assessed the Kupperman index for climacteric symptoms and the menopause-specific quality of life (MENQOL) questionnaire for quality of the life. Biomarkers of bone metabolism were also measured in serum bone-specific alkaline phosphatase (BALP), osteocalcin (OC), N- and C-terminal cross-linking telopeptides of type I collagen (NTx, CTx), and urine-deoxypyridinolin (u-DPD).

RESULTS

Scores of the Kupperman index were decreased in both the isoflavones group (-7.0 ± 15.8, P = 0.0074) and placebo group (-6.3 ± 14.6, P = 0.0064) during the intervention, but no significant difference was noted between the groups. Regarding the bone formation markers, the level of serum BALP increased by 6.3 ± 4.1% (P = 0.004) and OC increased by 9.3 ± 6.2% (P < 0.001), meanwhile those of the placebo were not changed. For the bone resorption markers, NTx, CTx, and u-DPD were not significantly different in either group. MENQOL was significant decreased in the isoflavone group (-0.6 ± 0.5) and placebo group (-0.6 ± 0.4), with a significant difference between groups (P = 0.0228).

CONCLUSIONS

Our study suggests that 70 mg isoflavones supplement has beneficial effects on bone formation markers; however, it showed no benefit compared to the placebo on climacteric symptoms or quality of life.

Consensus: soy isoflavones as a first-line approach to the treatment of menopausal vasomotor complaints

The association between an increased uptake of isoflavones and a reduced frequency of menopausal hot flushes was first described in 1992, based on a lower incidence of hot flushes in countries with a high consumption of soy. Since then, numerous clinical trials with various sources of isoflavones including soy and red clover have been presented, with practically all of the studies with adequate design delivering an outcome in favour of isoflavone supplementation. An in-depth risk assessment (EFSA 2015) concludes that the amply available human data does not indicate any suspected harmful effects from a potential interaction of isoflavones with hormone-sensitive tissues in the mammary gland, the uterus and the thyroid gland. Safety was ascertained with long-term intake of up to 150 mg isoflavones per day ingested for the duration of at least 3 years. Moreover, high isoflavone intake was found to have preventive effects with respect to breast cancer. Clinical findings indicate potential benefits of isoflavone exposure even during breast cancer treatment with tamoxifen or anastrozole.

Glycone-rich Soy Isoflavone Extracts Promote Estrogen Receptor Positive Breast Cancer Cell Growth

Due to the association of hormone replacement therapy (HRT) with breast cancer risk, estrogenically active soy isoflavones are considered as an HRT alternative to alleviate menopausal symptoms. However, several recent reports challenged the health benefits of soy isoflavones and associated them with breast cancer promotion. While glyconic isoflavones are the major constituents of soybean seeds, due to their low cell permeability, they are considered to be biologically inactive. The glyconic isoflavones may exert their effects on membrane-bound estrogen receptors or could be converted to aglycones by extracellular β-glucosidases. Therefore, we hypothesized that despite their low cell permeability, soybean cultivars with high glyconic isoflavones may promote breast cancer cell growth. To test this, composition and estrogenic activity of isoflavones from 54 commercial soybean cultivars were determined. Soybean seeds produced in identical climate and growth conditions were used to minimize the effects of extraneous factors on isoflavone profile and concentrations. The glyconic daidzin concentration negatively correlated with genistin and with other aglycones. Relative to control, isoflavone extracts from 51 cultivars were estrogenic and promoted the growth of estrogen receptor positive (ER+) breast cancer cell line MCF-7 from 1.14 to 4.59 folds and other three cultivars slightly reduced the growth. Among these, extracts from three cultivars were highly estrogenic and promoted MCF-7 cell growth by 2.59-4.64 folds (P<0.005). Among six isoflavones, daidzin was positively associated with MCF-7 cell growth (P<0.005, r = 0.13966), whereas the negative correlation between genistin and MCF-7 cell growth was nearly significant (P≤0.0562, r = -0.026141). Furthermore, in drug interaction studies daidzin-rich isoflavone extracts antagonized tamoxifen, an ER inhibitor. Taken together, our results suggest that the glyconic daidzin-rich soy isoflavone extracts may exert estrogenic effects and promote ER+ breast cancer growth.

The application of soy isoflavones for subjective symptoms and objective signs of vaginal atrophy in menopause: A systematic review of randomised controlled trials

Vaginal atrophy is a common complaint among many women in their menopause, presenting with a cluster of symptoms including dryness, itching, burning/soreness, discharge, irritation and painful intercourse. We searched for existing pertinent data in three chief registries. Specified time brackets included 1996-2013 for Medline, 1990-2013 for Scopus and 2013 for Cochrane Central Register of Controlled Trials (issue 1). Of 110 potentially relevant publications, 17 and 9 trials (7 on maturation value and 2 on vaginal dryness) were selected for qualitative and quantitative analysis, respectively. In general, soy isoflavones seem to improve vaginal symptoms as opposed to control arms. Soy isoflavones were also shown to be more efficacious in quantitative analysis, though this was statistically non-significant. Standardised difference in means of maturation value change was 0.072 (95% confidence interval [CI]: - 0.42 to 0.57), p = 0.777; heterogeneity P = 0.00; I(2) = 85.15%. Difference in means of vaginal dryness was - 0.204 (95% CI: - 0.28 to - 0.126), p < 0.001; heterogeneity P = 0.423; I(2) = 0.00. Soy isoflavones may relieve vaginal symptoms during menopause; nevertheless beneficial effects still remain uncertain due to possible publication bias or vast heterogeneity of the selected studies. Further studies with consistency in design as well as statistics are warranted.

Efficacy of phytoestrogens for menopausal symptoms: a meta-analysis and systematic review

OBJECTIVE

To perform a meta-analysis examining the efficacy of phytoestrogens for the relief of menopausal symptoms.

METHODS

Medline, Cochrane, EMBASE, and Google Scholar databases were searched until September 30, 2013 using the following key words: vasomotor symptoms, menopausal symptoms, phytoestrogens, isoflavones, coumestrol, soy, red clover. Inclusion criteria were (1) randomized controlled trial (RCT), (2) perimenopausal or postmenopausal women experiencing menopausal symptoms, (3) intervention with an oral phytoestrogen. Outcome measures included Kupperman index (KI) changes, daily hot flush frequency, and the likelihood of side-effects.

RESULTS

Of 543 potentially relevant studies identified, 15 RCTs meeting the inclusion criteria were included. The mean age of the subjects ranged from 49 to 58.3 and 48 to 60.1 years, respectively, in the placebo and phytoestrogen groups. The number of participants ranged from 30 to 252, and the intervention periods ranged from 3 to 12 months. Meta-analysis of the seven studies that reported KI data indicated no significant treatment effect of phytoestrogen as compared to placebo (pooled mean difference = 6.44, p = 0.110). Meta-analysis of the ten studies that reported hot flush data indicated that phytoestrogens result in a significantly greater reduction in hot flush frequency compared to placebo (pooled mean difference = 0.89, p < 0.005). Meta-analysis of the five studies that reported side-effect data showed no significant difference between the two groups (p = 0.175).

CONCLUSION

Phytoestrogens appear to reduce the frequency of hot flushes in menopausal women, without serious side-effects.

A systematic review of non-hormonal treatments of vasomotor symptoms in climacteric and cancer patients

The cardinal climacteric symptoms of hot flushes and night sweats affect 24-93% of all women during the physiological transition from reproductive to post-reproductive life. Though efficacious, hormonal therapy and partial oestrogenic compounds are linked to a significant increase in breast cancer. Non-hormonal treatments are thus greatly appreciated.

This systematic review of published hormonal and non-hormonal treatments for climacteric, and breast and prostate cancer-associated hot flushes, examines clinical efficacy and therapy-related cancer risk modulation.

A PubMed search included literature up to June 19, 2014 without limits for initial dates or language, with the search terms, (hot flush* OR hot flash*) AND (clinical trial* OR clinical stud*) AND (randomi* OR observational) NOT review). Retrieved references identified further papers. The focus was on hot flushes; other symptoms (night sweats, irritability, etc.) were not specifically screened. Included were some 610 clinical studies where a measured effect of the intervention, intensity and severity were documented, and where patients received treatment of pharmaceutical quality. Only 147 of these references described studies with alternative non-hormonal treatments in post-menopausal women and in breast and prostate cancer survivors; these results are presented in Additional file 1.

The most effective hot flush treatment is oestrogenic hormones, or a combination of oestrogen and progestins, though benefits are partially outweighed by a significantly increased risk for breast cancer development.

This review illustrates that certain non-hormonal treatments, including selective serotonin reuptake inhibitors, gabapentin/pregabalin, and Cimicifuga racemosa extracts, show a positive risk-benefit ratio.

Key points

Several non-hormonal alternatives to hormonal therapy have been established and registered for the treatment of vasomotor climacteric symptoms in peri- and post-menopausal women.

There are indications that non-hormonal treatments are useful alternatives in patients with a history of breast and prostate cancer. However, confirmation by larger clinical trials is required.

Effects of a phyto complex on well-being of climacteric women

AIM

The aim of this study was to assess the effects of a phyto complex on menopausal symptoms.

MATERIAL AND METHODS

A total of 151 women aged 42-67 years were enrolled. They were in spontaneous or surgical menopause by at least 12 months, reporting symptoms referable to the climacteric syndrome. Two validated and standardized tests were given to the whole sample at the entrance of the study (T0) and after 6 months of treatment (T6): the Greene Climacteric Scale (GCS) and the Beck Depression Inventory (BDI). Interim evaluations were carried out at 1-3 months (T1 and T3) on five symptoms selected from the GCS. The phyto complex was given to each enrolled woman, from the T0 to T6 time-points, for a total of 180 days.

RESULTS

At the T0 time-point, the average scores were: GCS, 28.98 (standard deviation [SD] ± 10.71); BDI, 14.48 (SD ± 6.5). At the T1 time-point, five parameters of the GCS were assessed with a reduction of 36.25% in symptoms (5.69, SD ± 3.53). At the T6 time-point the assessment was completed: average GCS results were 11.54 (SD ± 8.01) with a 60.17% improvement; and average BDI results were 6.11 (SD ± 4.6) with a 58.91% improvement in the depressive symptoms.

CONCLUSIONS

The phyto complex under consideration is an effective tool to counter, in a quick and long-lasting manner, the most common and nagging symptoms of the climacteric syndrome, such as hot flushes, insomnia and depression.

Effects of Glycine max (L.) Merr. soy isoflavone vaginal gel on epithelium morphology and estrogen receptor expression in postmenopausal women: a 12-week, randomized, double-blind, placebo-controlled trial

OBJECTIVE

Evaluate the effects of vaginal administration of isoflavones derived from Glycine max (L.) Merr. as a treatment option for vaginal atrophy, on the morphology and expression of estrogen receptors in vaginal epithelium of postmenopausal women.

METHODS

The double-blind, randomized, placebo-controlled, clinical trial. Sixty women were treated for 12 weeks with isoflavone vaginal gel 4% (1g/day) and a placebo gel. After 4 and 12 weeks, the vaginal atrophy symptoms were classified at none, mild, moderate and severe and the vaginal cytology were taken to determine the maturation value. Vaginal pH was measured at the beginning and end of therapy. Microbiopsies in vaginal fornix were performed before the treatment and after 12 weeks of treatment.

RESULTS

Isoflavone vaginal gel was effective for relief of vaginal dryness and dyspareunia symptons and an increase in the intermediate and superficial cells was noted. The vaginal pH in the isoflavone group was 7.1 at baseline and 5.4 after 12 weeks, whereas in the placebo group there was no significant change. A significant increase in thickness after treatment was detected in the Isoflavone Group. The percentage of estrogen receptor positive cells in vaginal epithelium for the Isoflavone Group ranged from 58.5% at the beginning of treatment to 82.6% after 12 weeks. These results were superior to placebo gel.

CONCLUSION

Glycine max (L.) Merr. at 4% vaginal gel on a daily basis in postmenopausal women led to improvements in vaginal atrophy symptoms, maturation values, vaginal pH, morphology and expression of estrogen receptors in vaginal epithelium. Isoflavones proved good treatment options for relief of vulvovaginal atrophy.

Phytoestrogens for menopausal vasomotor symptoms

BACKGROUND

Vasomotor symptoms, such as hot flushes and night sweats, are very common during the menopausal transition. Hormone therapy has traditionally been used as a highly effective treatment, but concerns about increased risk of some chronic diseases have markedly increased the interest of women in alternative treatments. Some of the most popular of these treatments are foods or supplements enriched with phytoestrogens-plant-derived chemicals that have estrogenic action.

OBJECTIVES

To assess the efficacy, safety and acceptability of food products, extracts and dietary supplements containing high levels of phytoestrogens when compared with no treatment, placebo or hormone therapy for the amelioration of vasomotor menopausal symptoms (such as hot flushes and night sweats) in perimenopausal and postmenopausal women.

SEARCH METHODS

Searches targeted the following electronic databases: the Cochrane Menstrual Disorders and Subfertility Group Specialised Register of randomised trials (29 July 2013), the Cochrane Register of Controlled Trials (CENTRAL; 29 July 2013), MEDLINE (inception to 29 July 2013), EMBASE (inception to 29 July 2013), AMED (1985 to 29 July 2013), PsycINFO (inception to 29 July 2013) and CINAHL (inception to 29 July 2013). Attempts were made to access grey literature by sending letters to pharmaceutical companies and performing searches of ongoing trial registers. Reference lists of included trials were also searched.

SELECTION CRITERIA

Studies were included if they were randomised, included perimenopausal or postmenopausal participants with vasomotor symptoms (hot flushes or night sweats), lasted at least 12 weeks and provided interventions such as foods or supplements with high levels of phytoestrogens (not combined with other herbal treatments). Trials that included women who had breast cancer or a history of breast cancer were excluded.

DATA COLLECTION AND ANALYSIS

Selection of trials, extraction of data and assessment of quality were undertaken by at least two review authors. Most trials were too dissimilar for their results to be combined in a meta-analysis, so these findings are provided in narrative 'Summary of results' tables. Studies were grouped into broad categories: dietary soy, soy extracts, red clover extracts, genistein extracts and other types of phytoestrogens. Five trials used Promensil, a red clover extract; results of these trials were combined in a meta-analysis, and summary effect measures were calculated.

MAIN RESULTS

A total of 43 randomised controlled trials (4,364 participants) were included in this review. Very few trials provided data suitable for inclusion in a meta-analysis. Among the five trials that yielded data assessing the daily frequency of hot flushes suitable for pooling, no significant difference overall was noted in the incidence of hot flushes between participants taking Promensil (a red clover extract) and those given placebo (mean difference (MD) -0.93, 95% confidence interval (CI) -1.95 to 0.10, I(2) = 31%). No evidence indicated a difference in percentage reduction in hot flushes in two trials between Promensil and placebo (MD 20.15, 95% CI -12.08 to 52.38, I(2) = 82%). Four trials that were not combined in meta-analyses suggested that extracts with high (> 30 mg/d) levels of genistein consistently reduced the frequency of hot flushes. Individual results from the remaining trials were compared in broad subgroups such as dietary soy, soy extracts and other types of phytoestrogens that could not be combined. Some of these trials found that phytoestrogen treatments alleviated the frequency and severity of hot flushes and night sweats when compared with placebo, but many trials were small and were determined to be at high risk of bias. A strong placebo effect was noted in most trials, with a reduction in frequency ranging from 1% to 59% with placebo. No indication suggested that discrepant results were due to the amount of isoflavone in the active treatment arm, the severity of vasomotor symptoms or trial quality factors. Also, no evidence indicated that these treatments caused oestrogenic stimulation of the endometrium or the vagina or other adverse effects when used for up to two years.

AUTHORS' CONCLUSIONS

No conclusive evidence shows that phytoestrogen supplements effectively reduce the frequency or severity of hot flushes and night sweats in perimenopausal or postmenopausal women, although benefits derived from concentrates of genistein should be further investigated.

Effects of soy isoflavones on mammographic density and breast parenchyma in postmenopausal women: a randomized, double-blind, placebo-controlled clinical trial

OBJECTIVE

This study aims to evaluate the effects of soy isoflavones on breast tissue in postmenopausal women.

METHODS

In this randomized, double-blind, placebo-controlled study, 80 women (aged ≥ 45 y and with amenorrhea >12 mo) with vasomotor symptoms were randomized to receive either 250 mg of standardized soy extract corresponding to isoflavone 100 mg/day (n = 40) or placebo (n = 40) for 10 months. Breasts were evaluated through mammographic density and breast parenchyma using ultrasound (US) at baseline and 10-month follow-up. Independent t test, analysis of variance, Mann-Whitney U test, and χ2 trend test were used in statistical analysis.

RESULTS

Baseline clinical characteristics showed no significant differences between the isoflavone group and the placebo group, with mean (SD) age of 55.1 (6.0) and 56.2 (7.7) years, mean (SD) menopause duration of 6.6 (4.8) and 7.1 (4.2) years, and mean (SD) body mass index of 29.7 (5.0) and 28.5 (4.9) kg/m2, respectively (P > 0.05). The study was completed by 32 women on isoflavone and 34 women on placebo. The groups did not differ in mammographic density or breast parenchyma by US (P > 0.05). Within each group, the baseline and final moments did not differ in mammography or US parameters significantly (P > 0.05).

CONCLUSIONS

The use of soy isoflavone extract for 10 months does not affect breast density, as assessed by mammography and US, in postmenopausal women.

Isoflavones for hypercholesterolaemia in adults

BACKGROUND

Hypercholesterolaemia is a significant risk factor for cardiovascular diseases. Isoflavones may be effective in improving hypercholesterolaemia.

OBJECTIVES

To assess the effects of isoflavones for hypercholesterolaemia.

SEARCH METHODS

We searched the following databases: The Cochrane Library (Issue 9, 2012), MEDLINE, EMBASE, Chinese BioMedical Database and China National Knowledge Infrastructure (all to September 2012).

SELECTION CRITERIA

We considered randomized controlled clinical trials in hypercholesterolaemic participants comparing isoflavones versus placebo, or soy isolated protein added with isoflavones versus soy isolated protein alone.

DATA COLLECTION AND ANALYSIS

Two review authors independently abstracted relevant population and intervention characteristics. We resolved any disagreements through discussion, or if required by a third party. We assessed the risk of bias of trials against key criteria: random sequence generation, allocation concealment, blinding of participants and personnel, blinding of outcome assessment, incomplete outcome data, selective reporting and other sources of bias.

MAIN RESULTS

We included five randomized trials (208 participants, 104 in the intervention group and 104 in the control group). Interventions ranged from three to six months. Four trials reported results in non-Asian populations published in English. One trial reported results in Chinese people published in Chinese. Overall, the risk of bias of included trials was high or unclear. There were no outcome data on death from any cause, morbidity, complications, health-related quality of life and costs. Two trials reported adverse effects, including gastrointestinal discomfort (bloating and constipation) and an increased number of hot flushes. None of the trials found serious adverse events. There was a slight significant effect on triglycerides in favour of isoflavones when compared with placebo (mean difference (MD) -0.46 mmol/L (95% confidence interval (CI) -0.84 to -0.09; P = 0.02; 52 participants; 2 trials). No statistically significant effects on total cholesterol, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol were shown in favour of isoflavones.

AUTHORS' CONCLUSIONS

We found no evidence for effects of isoflavones on patient-important outcomes or lowering of cholesterol levels in people with hypercholesterolaemia. Our findings have to be interpreted with caution due to high or unclear risk of bias in several risk of bias domains, and low number of participants in trials.

Evaluation of contextual and demographic factors on licorice effects on reducing hot flashes in postmenopause women

Menopause is an important stage in the life of every woman. Hot flashes are the most common climacteric symptom and a major cause of suffering in postmenopausal women. Licorice is one of the plants that is used to relieve menopausal symptoms. The present study was undertaken to evaluate the effects of licorice on hot flash symptoms in menopausal women. The participants of this randomized, double blind, clinical trial study were 60 menopausal women randomly allocated to licorice or hormone replacement therapy (HRT) groups. The participants in this trial received licorice (1140 mg/day) or HRT (a conjugated estrogen 0.312 mg/day and Medroxyprogesterone 2.5 mg/day) for 90 days. In this study we observed that licorice is not very different from hormones in terms of reducing the number and duration of hot flashes, but that HRT can reduce the severity of hot flashes significantly better than licorice can. In addition, there was no significant difference between age, education level, marital status, occupation, income, number of pregnancies, time from cessation of menstruation, and severity of hot flashes in the two groups. We observed that licorice seems more effective than HRT in improving hot flash duration, but that HRT can reduce the duration and severity of hot flashes more than licorice.

Isoflavone supplementation influenced levels of triglyceride and luteunizing hormone in Korean postmenopausal women

We conducted a double-blind, randomized, placebo-controlled trial to evaluate the effects of soy-derived isoflavone on blood glucose, lipid profiles, and sex hormones related to cardiovascular disease in Korean postmenopausal women. One hundred thirteen postmenopausal women were recruited from the Seoul metropolitan area. To confirm postmenopausal and gynecologic status, the subjects were clinically examined by a gynecologist using ultra sound and X-ray. Finally, 85 postmenopausal women whose follicle-stimulating hormone (FSH) levels were higher than 40 IU/ml were enrolled. Subjects received either 70 mg isoflavone or placebo capsules daily for 12 weeks. As a result, the values of fasting glucose, insulin and HOMA-IR, as well as those of TC, LDL-C, HDL-C and FFA, were not different between the groups after supplementation. However, triglyceride (TG) levels in the treatment group decreased significantly compared with those of the placebo group (p = 0.0215). The levels of luteinizing hormone (LH) significantly decreased in the treatment group (p = 0.027); however, the levels of FSH, estrone and estradiol were not changed after intervention. In conclusion, isoflavone supplement of 70 mg/day for 12 weeks decreased blood levels of TG and LH in Korean postmenopausal women.

The role of soy isoflavones in menopausal health: report of The North American Menopause Society/Wulf H. Utian Translational Science Symposium in Chicago, IL (October 2010)

OBJECTIVES

If and to what extent soy protein, soy isoflavones, and their metabolites, including S(--)-equol, have beneficial effects on women's health is currently unclear. The North American Menopause Society (NAMS)/Utian Translational Science Symposium on Soy and Soy Isoflavones convened October 9-10, 2010, to clarify basic and clinical research findings as they relate to the risk and benefits of soy products for peri- and postmenopausal women.

METHODS

A working group of faculty and panelists composed of clinical and research experts in the fields of women's health and botanicals met during a 2-day translational symposium to cover the latest evidence-based science on isoflavones as they affect menopausal symptoms, breast and endometrial cancer, atherosclerosis, bone loss, and cognition. Full descriptions of the bioavailability and pharmacokinetics of isoflavones were also presented. Subspecialty groups then broke off with the goal of translating the information into a report for general medical practice and identifying further research areas. All faculty and panelists reviewed the final report, which was then approved by the NAMS Board of Trustees.

RESULTS

From the hundreds of studies reviewed in this report, there are mixed results of the effects on midlife women. Soy-based isoflavones are modestly effective in relieving menopausal symptoms; supplements providing higher proportions of genistein or increased in S(--)-equol may provide more benefits. Soy food consumption is associated with lower risk of breast and endometrial cancer in observational studies. The efficacy of isoflavones on bone has not been proven, and the clinical picture of whether soy has cardiovascular benefits is still evolving. Preliminary findings on cognitive benefit from isoflavone therapy support a "critical window" hypothesis wherein younger postmenopausal women derive more than older women.

CONCLUSIONS

Several areas for further research have been identified on soy and midlife women. More clinical studies are needed that compare outcomes among women whose intestinal bacteria have the ability to convert daidzein to equol (equol producers) with those that lack that ability (equol nonproducers) in order to determine if equol producers derive greater benefits from soy supplementation. Larger studies are needed in younger postmenopausal women, and more research is needed to understand the modes of use of soy isoflavone supplements in women. The interrelations of other dietary components on soy isoflavones consumed as a part of diet or by supplement on equol production also require further study, as do potential interactions with prescription and over-the-counter medications. And finally, greater standardization and documentation of clinical trial data of soy are needed.

The effect of soy-derived isoflavones over hot flushes, menopausal symptoms and mood in climacteric women with increased body mass index

BACKGROUND

Risk-benefit issues raised after the WHI have significantly increased the use of alternative treatments for the menopause. Despite this, data regarding the effect of soy isoflavones over mood and menopausal symptoms in high risk populations is still lacking.

OBJECTIVE

To evaluate the effect of soy derived isoflavones over hot flushes, menopausal symptoms and mood in climacteric women with increased body mass index (BMI).

METHODS

Fifty symptomatic climacteric women aged 40 to 59 with increased BMI (≥ 25) were recruited to receive oral 100 mg/day of soy derived isoflavones (Climasoy) for 3 months. Hot flushes (frequency/intensity), menopausal symptoms (Menopause Rating Scale [MRS]) and mood (Hamilton Depressive Rating Scale [HDRS]) were evaluated at baseline and at 90 days.

RESULTS

A total of 45 women completed the study. After 3 months of soy isoflavone supplementation hot flushes significantly decreased in percentage, number and severity (100% to 31.1%; 3.9 ± 2.3 to 0.4 ± 0.8 and 2.6 ± 0.9 to 0.4 ± 0.8, respectively, p < 0.001). MRS scores (total and for subscales) reflecting general menopausal symptoms also significantly decreased compared to baseline. Regarding mood, after three months total HDRS scores and the rate of women presenting depressed mood (scores ≥ 8) significantly decreased (16.3 ± 5.4 to 6.9 ± 5.2 and 93.3% to 28.9%, respectively, p < 0.05). There was no effect on blood pressure levels or BMI values after treatment.

CONCLUSION

In this high risk climacteric population, soy derived isoflavone treatment improved mood as well as vasomotor and general menopausal symptoms. More research is required to determine if the positive effect over mood is a direct or an indirect one through hot flush alleviation.

Equol: pharmacokinetics and biological actions

Equol [7-hydroxy-3-(4'-hydroxyphenyl)-chroman], an isoflavan produced by intestinal bacteria in response to soy isoflavone intake in some but not all humans, exhibits a wide range of biological properties. It exists as the diastereoisomers S-(-)equol and R-(+)equol. Intestinal bacteria produce exclusively S-(-)equol, which has selective affinity for estrogen receptor (ER)-beta. The evidence is conflicting on whether there is an advantage to producing S-(-)equol in response to soy isoflavone intakes, but the ability to now synthesize these diastereoisomers opens the way for future clinical trials to directly examine their potential in a number of hormone-dependent conditions. In this review, the plasma and urinary pharmacokinetics of S-(-)equol and R-(+)equol are reviewed and summarized, and some of the more recent evidence supporting potential biological effects of S-(-)equol is considered.

Bioactivity of isoflavones: assessment through a theoretical model as a way to obtain a "Theoretical Efficacy Related to Estradiol (TERE)"

The increase of human life span will have profound implications in Public Health in decades to come. By 2030, there will be an estimated 1.2 billion women in post-menopause. Hormone Replacement Therapy with synthetic hormones is still full of risks and according to the latest developments, should be used for the shortest time possible. Searching for alternative drugs is inevitable in this scenario and science must provide physicians with other substances that can be used to treat the same symptoms with less side effects. Systematic research carried out on this field of study is focusing now on isoflavones but the randomised controlled trials and reviews of meta-analysis concerning post-menopause therapy, that could have an important impact on human health, are very controversial. The aim of the present work was to establish a theoretical calculation suitable for use as a way to estimate the “Theoretical Efficacy (TE)” of a mixture with different bioactive compounds as a way to obtain a “Theoretical Efficacy Related to Estradiol (TERE)”. The theoretical calculation that we propose in this paper integrates different knowledge about this subject and sets methodological boundaries that can be used to analyse already published data. The outcome should set some consensus for new clinical trials using isoflavones (isolated or included in mixtures) that will be evaluated to assess their therapeutically activity. This theoretical method for evaluation of a possible efficacy could probably also be applied to other herbal drug extracts when a synergistic or contradictory bio-effect is not verified. In this way, it we may contribute to enlighten and to the development of new therapeutic approaches.

Soy extract phytoestrogens with high dose of isoflavones for menopausal symptoms

AIM

The aim of the present study was to assess the efficacy and safety of a standardized compound based on an extract of soy phytoestrogens, with high doses of isoflavones in the management of menopausal hot flushes.

METHODS

A total of 180 women aged 40-65 years with a minimum of five moderate-to-severe hot flushes in the last 7 days at baseline and absence of menstruation for at least 6 months participated in a 12-week prospective, randomized, double-blind, placebo-controlled multicenter trial. After a 2-week run-in period, women received one tablet a day of 80 mg isoflavones (corresponding to 60 mg of genistein) or a matching placebo.

RESULTS

The mean daily number of moderate-to-severe hot flushes decreased in both study groups, but the reduction was greater in the isoflavones arm at 6 (36.2%) and 12 weeks (41.2%) than in the placebo arm (24.0% at 6 weeks, 29.3% at 12 weeks), with a difference of 1.1 (95% CI [-2.0 to -0.06]) (P = 0.038) at 6 weeks and 1.1 (95% CI [-2.05 to -0.15]) (P = 0.023) at 12 weeks. Similar findings were obtained for hot flushes of any intensity. The Kupperman index decreased in both study groups. Relief of hot flushes was greater when time to menopause was >or=12 months and in cases of BMI >or=27 kg/m(2).

CONCLUSION

In daily practice conditions, high doses of isoflavones, particularly genistein, can be used for the management of hot flushes in postmenopausal women not treated with hormone replacement therapy due to their superior efficacy to placebo and very good safety profile.

Effects of the phytoestrogen genistein on hot flushes, endometrium, and vaginal epithelium in postmenopausal women: a 2-year randomized, double-blind, placebo-controlled study

OBJECTIVE

To evaluate in a 24-month, prospective, randomized, double-blind, placebo-controlled study whether pure administration of the phytoestrogen genistein (54 mg/d) might reduce the number and severity of hot flushes in postmenopausal women, with no adverse effect on the endometrium and vagina.

METHODS

A total of 389 participants met the parent study criteria and were randomly assigned to receive the phytoestrogen genistein (n = 198) or placebo (n = 191). About 40% of participants in both groups did not experience hot flushes, and the evaluation was performed in a subgroup of 236 participants (genistein, n = 119; placebo, n = 117). Reductions from the baseline in the frequency and severity of hot flushes were the principal criteria of efficacy. Endometrial thickness was evaluated by ultrasonography. The maturation value was also used to determine hormonal action on the vaginal cells.

RESULTS

There were no significant differences in vasomotor symptoms between groups at the baseline (4.4 +/- 0.33 hot flushes per day in the genistein group and 4.2 +/- 0.35 hot flushes per day in the control group). After 12 months of genistein therapy, there was a significant reduction (-56.4%) in the mean number of hot flushes, with a significant difference compared with the control group. After 24 months, there was no further decrease in the number of hot flushes in both groups. No significant difference was found in mean endometrial thickness and the maturation value score between the two groups, either at the baseline or after 24 months.

CONCLUSIONS

The phytoestrogen genistein has been shown to be effective on vasomotor symptoms without an adverse effect on the endometrium and vagina, but after the first year, there was no further improvement in the decrease in hot flushes.

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.

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.

Effects of extracted soy isoflavones alone on blood total and LDL cholesterol: Meta-analysis of randomized controlled trials

When provided concurrently with soy protein for 1-3 months, soy isoflavones exert synergistic or additive cholesterol-lowering effects. This meta-analysis was performed to evaluate the effects of extracted soy isoflavones alone (not ingested concurrently with soy protein) on total and low density lipoprotein (LDL) cholesterol. MEDLINE (1966-2007), EMBASE (1966-2007), CENTRAL (1966-2007), ICHUSHI (1983-2008), and CNKI (1979-2007) were searched for randomized placebo-controlled trials published in English, Japanese, and Chinese, describing the changes in lipid profiles in adult humans resulting from ingestion of extracted soy isoflavones for 1-3 months. Reference lists of relevant systematic reviews and meta-analyses were hand-searched. Meta-analysis of 10 and 9 trials with usable information using REVMAN found that an average of 70 mg soy isoflavones/day (27-132 mg, as the aglycone form) alone had a nonsignificant effect on total (0.01 mmol/L [95% CI: -0.12, 0.14]; P = 0.86) and LDL (0.03 mmol/L [95% CI: -0.11, 0.16]; P = 0.71) cholesterol in menopausal women, respectively. It is concluded that ingestion of about 70 mg extracted soy isoflavones/day alone for 1-3 months does not improve total and LDL cholesterol levels in normocholesterolemic menopausal women; further studies are needed to verify the effects of extracted soy isoflavones.

Liquiritigenin is a plant-derived highly selective estrogen receptor beta agonist

After the Women's Health Initiative found that the risks of hormone therapy outweighed the benefits, a need for alternative drugs to treat menopausal symptoms has emerged. We explored the possibility that botanical agents used in Traditional Chinese Medicine for menopausal symptoms contain ERbeta-selective estrogens. We previously reported that an extract containing 22 herbs, MF101 has ERbeta-selective properties. In this study we isolated liquiritigenin, the most active estrogenic compound from the root of Glycyrrhizae uralensis Fisch, which is one of the plants found in MF101. Liquiritigenin activated multiple ER regulatory elements and native target genes with ERbeta but not ERalpha. The ERbeta-selectivity of liquiritigenin was due to the selective recruitment of the coactivator steroid receptor coactivator-2 to target genes. In a mouse xenograph model, liquiritigenin did not stimulate uterine size or tumorigenesis of MCF-7 breast cancer cells. Our results demonstrate that some plants contain highly selective estrogens for ERbeta.

Effects of isoflavones on the coagulation and fibrinolytic system of postmenopausal women

OBJECTIVE

We evaluated the effects of soy isoflavone supplementation on hemostasis in healthy postmenopausal women.

METHODS

In this double-blinded, placebo-controlled study, 47 postmenopausal women 47-66 y of age received 40 mg of soy isoflavone (n = 25) or 40 mg of casein placebo (n = 22) once a day for 6 mo. Levels of factors VII and X, fibrinogen, thrombin-antithrombin complex, prothrombin fragments 1 plus 2, antithrombin, protein C, total and free protein S, plasminogen, plasminogen activator inhibitor-1, and D-dimers were measured at baseline and 6 mo. Urinary isoflavone concentrations (genistein and daidzein) were measured as a marker of compliance and absorption using high-performance liquid chromatography. Baseline characteristics were compared by unpaired Student's t test. Within-group changes and comparison between the isoflavone and casein placebo groups were determined by a mixed effects model.

RESULTS

The levels of hemostatic variables did not change significantly throughout the study in the isoflavone group; however, the isoflavone group showed a statistically significant reduction in plasma concentration of prothrombin fragments 1 plus 2; both groups showed a statistically significant reduction in antithrombin, protein C, and free protein S levels. A significant increase in D-dimers was observed only in the isoflavone group. Plasminogen activator inhibitor-1 levels increased significantly in the placebo group. However, these changes were not statistically different between groups.

CONCLUSION

The results of the present study do not support a biologically significant estrogenic effect of soy isoflavone on coagulation and fibrinolysis in postmenopausal women. However, further research will be necessary to definitively assess the safety and efficacy of isoflavone.

Efficacy and safety of a soy isoflavone extract in postmenopausal women: a randomized, double-blind, and placebo-controlled study

OBJECTIVE

To investigate the efficacy of soy isoflavone on climacteric symptoms in postmenopausal women.

DESIGN

In this double-blind, randomized, placebo-controlled study, a total of 80 women (mean age = 55.1 years), who reported 5 or more hot flush episodes per day, were randomized to receive either 250 mg of standardized soy extract (Glycine max AT) a total of 100mg/day of isoflavone (n = 40) or placebo (n = 40). Exclusion criteria included: contra-indication for hormone therapy (HT), chronic gastrointestinal diseases, and users of HT within the preceding 6-months. For 10-months, climacteric symptoms were evaluated using a score card and the menopausal Kupperman index. Compliance and safety were also assessed. At baseline and the end of the study, lipid and hormonal profiles, as well as vaginal, mammographic and ultrasonographic parameters were measured. The t-test, Wilcoxon test and ANOVA were used in the statistical analysis.

RESULTS

At baseline, the mean number of hot flushes was 9.6 +/- 3.9 per day in the isoflavone group and 10.1+/-4.9 in the placebo group (p>0.05). After 10 months, there was a significant reduction in frequency of hot flushes among isoflavone users when compared to those on placebo (3.1 +/- 2.3 and 5.9 +/- 4.3, respectively) (p<0.001). Kupperman index mean values showed a significant reduction in both groups. However, soy isoflavone was significantly superior to placebo, in reducing hot flush severity (69.9% and 33.7%, respectively) (p<0.001). Endometrial thickness, mammography, vaginal cytology, lipids and hormonal profile did not change in both groups. No serious adverse event related to isoflavone treatment was reported.

CONCLUSIONS

The soy isoflavone extract exerted favorable effects on vasomotor symptoms and good compliance, providing a safe and effective alternative therapeutic for postmenopausal women.

Phytoestrogens for vasomotor menopausal symptoms

BACKGROUND

Vasomotor symptoms, such as hot flushes and night sweats, are very common during the menopausal transition. Hormone replacement therapy has traditionally been used as a very effective treatment but concerns over increased risks of some chronic diseases have markedly increased the interest of women in alternatives. Some of the most popular of these are treatments based on foods or supplements enriched with phytoestrogens, plant-derived chemicals that have oestrogenic action.

OBJECTIVES

To assess the efficacy, safety and acceptability of foods and supplements based on high levels of phytoestrogens for reducing hot flushes and night sweats in postmenopausal women.

SEARCH STRATEGY

Searches were undertaken of the following electronic databases: the Cochrane Menstrual Disorders and Subfertility Group Specialised Register of randomised trials, Cochrane Register of Controlled Trials (CENTRAL) (March 2007), MEDLINE (1966 to March 2007), EMBASE (1980 to March 2007), AMED (1985 to March 2007), PsycINFO (1986 to March 2007) and CINAHL (1982 to March 2007). Attempts were made to access grey literature by letters to pharmaceutical companies and searches of ongoing trial registers. Reference lists of included trials were also searched.

SELECTION CRITERIA

Studies were included if they were randomised, had peri- or postmenopausal participants with vasomotor symptoms, a duration of at least 12 weeks and where the intervention was a food or supplement with high levels of phytoestrogens (and not combined with other herbal treatments). Trials of women who had breast cancer or a history of breast cancer were excluded.

DATA COLLECTION AND ANALYSIS

Selection of trials, data extraction and quality assessment were undertaken by at least two authors. Most of the trials were too dissimilar to combine in meta-analysis and their results are provided in table format. Studies were grouped into broad categories: dietary soy, soy extracts, red clover extracts and other types of phytoestrogen. Five trials used Promensil, a red clover extract; these trials were combined in a meta-analysis and summary effect measures were calculated.

MAIN RESULTS

Thirty trials comparing phytoestrogens with control met the inclusion criteria. Very few trials had data suitable for combining in meta-analysis. Of the five trials with data suitable for pooling that assessed daily frequency of hot flushes, there was no significant difference overall in the frequency of hot flushes between Promensil (a red clover extract) and placebo (WMD=-0.6, 95% CI -1.8 to 0.6). There was no evidence of a difference in percentage reduction in hot flushes in two trials between Promensil and placebo (WMD=20.2, 95% CI -12.1 to 52.4). Individual results from the remaining trials were compared. Some of the trials found that phytoestrogen treatments alleviated the frequency and severity of hot flushes and night sweats when compared to placebo but many of the trials were of low quality and were underpowered. There was a strong placebo effect in most trials with a reduction in frequency ranging from 1% to 59% with placebo. There was no indication that the discrepant results were due to the amount of isoflavone in the active treatment arm, the severity of vasomotor symptoms or trial quality factors. There was also no evidence that the treatments caused oestrogenic stimulation of the endometrium (an adverse effect) when used for up to two years.

AUTHORS' CONCLUSIONS

There is no evidence of effectiveness in the alleviation of menopausal symptoms with the use of phytoestrogen treatments.

Pasta naturally enriched with isoflavone aglycons from soy germ reduces serum lipids and improves markers of cardiovascular risk

Most studies of soy and cholesterol have tested foods made from purified soy proteins containing mainly isoflavone glycosides. Fermented soy foods have mainly isoflavone aglycons and account for a high proportion of the soy protein source in Asia, where there is an inverse relationship between soy intake and serum cholesterol. The aim of this study was to compare a novel soy germ pasta, naturally enriched in isoflavone aglycons as a result of the manufacturing process, with conventional pasta for effects on serum lipids and other cardiovascular risk markers. In this randomized, controlled, parallel study design of 62 adults with hypercholesterolemia who consumed a Step II diet that included one 80-g serving/d of pasta, we measured serum lipids, high sensitivity C-reactive protein (hsCRP), urinary isoprostanes, and brachial artery flow-mediated vasodilatation at baseline and after 4 and 8 wk. The pasta delivered 33 mg of isoflavones and negligible soy protein and led to a serum isoflavone concentration of 222 +/- 21 nmol/L; 69% of subjects were equol producers. Soy germ pasta reduced serum total and LDL cholesterol by 0.47 +/- 0.13 mmol/L (P = 0.001) and 0.36 +/- 0.10 mmol/L (P = 0.002) more than conventional pasta, representing reductions from baseline of 7.3% (P = 0.001) and 8.6% (P = 0.002), respectively. Arterial stiffness (P = 0.003) and hsCRP (P = 0.03) decreased and improvements in all the above risk markers were greatest in equol producers. All measures returned to baseline when patients were switched to conventional pasta. In conclusion, pasta naturally enriched with isoflavone aglycons and lacking soy protein had a significant hypocholesterolemic effect beyond a Step II diet and improved other cardiovascular risk markers.

Effects of the phytoestrogen genistein on hot flushes, endometrium, and vaginal epithelium in postmenopausal women: a 1-year randomized, double-blind, placebo-controlled study

OBJECTIVE

To evaluate in a 12-month, prospective, randomized, double-blind, placebo-controlled study whether pure administration of the phytoestrogen genistein (54 mg/d) might reduce the number and severity of hot flushes in postmenopausal women with no adverse effect on the endometrium.

DESIGN

A total of 389 participants met the main study criteria and were randomly assigned to receive the phytoestrogen genistein (n=198) or placebo (n=191). About 40% of participants in both groups did not suffer from hot flushes, and the evaluation was performed in a subgroup of 247 participants (genistein, n=125; placebo, n=122). Reductions from baseline in the frequency and severity of hot flushes were the principal criteria of efficacy. Endometrial thickness was evaluated by ultrasonography. The maturation value was also used to determine hormonal action on the vaginal cells.

RESULTS

There were no significant differences in age, time since menopause, body mass index, and vasomotor symptoms between groups at baseline (4.4 +/- 0.33 hot flushes per day in the genistein group and 4.2 +/- 0.35 hot flushes per day in the control group). The effect was already evident in the first month and reached its peak after 12 months of genistein therapy (-56.4% reduction in the mean number of hot flushes). Furthermore, there was a significant difference between the two groups at each evaluation time (1, 3, 6, and 12 months). No significant difference was found in mean endometrial thickness and maturation value score between the two groups, either at baseline or after 12 months.

CONCLUSIONS

The phytoestrogen genistein has been shown to be effective on vasomotor symptoms without an adverse effect on endometrium.

Isoflavones--safe food additives or dangerous drugs?

The sales volume of products containing isoflavone has increased since the publication of the Women's Health Initiative. The many apparently contradictory results published on the effects of isoflavones on a variety of estrogen-regulated organs point to both beneficial as well as adverse effects on human health. It is of particular importance that psychovegetative climacteric complaints such as hot flushes are, if at all, only slightly influenced by isoflavones. The substances appear to have weak anti-osteoporotic effect. Their anti-atherosclerotic action is debatable, as not all authors find any beneficial effect on lipids. Most importantly, there is dispute as to whether isoflavones derived from soy or red clover have negative, positive or any effect at all on the mammary gland or endometrium. It is beyond any doubt that soy products may have cancer preventing properties in a variety of organs including the mammary gland. However, these properties may only be exerted if the developing organ was under the influence of isoflavones during childhood and puberty. This may also explain the often quoted "Japanese Phenomenon", the fact that breast cancer occurs to a lesser extent in Japanese women. When administered to isoflavone "inexperienced" women at the time of menopause, the phytoestrogens appear to share the same effects as estrogen used in classical preparations for hormone replacement therapy, i.e. they may stimulate the proliferation of endometrial and mammary gland tissue with at present unknown and unpredictable risk to these organs. Therefore, the following question arises for the clinician: Why should soy or red clover products containing isoflavone be recommended, if the positive effects are only negligible but the adverse effects serious?

Phytoestrogen exposure is associated with circulating sex hormone levels in postmenopausal women and interact with ESR1 and NR1I2 gene variants

In this large cross-sectional study, we investigated the relationship between phytoestrogen exposure and circulating sex hormones and sex hormone-binding globulin (SHBG) levels in 1988 healthy postmenopausal women and their interactions with polymorphisms in genes involved in estrogen signaling. Plasma estradiol, testosterone, androstenedione, estrone, and SHBG were measured. Urinary levels of five isoflavones (daidzein, genistein, glycitein, O-desmethylangolensin, and equol) and two lignans (enterodiol and enterolactone) were measured and used as biomarkers for dietary intakes. Eighteen polymorphisms in ESR1, ESR2, and NR1I2 genes were genotyped. Results showed that lignans were positively associated with plasma SHBG levels (eta(p)(2) = 1.2%; P < 0.001) and negatively associated with plasma testosterone (eta(p)(2) = 0.2%; P = 0.042). Equol was negatively associated with plasma estradiol levels (eta(p)(2) = 0.3%; P = 0.028), whereas O-desmethylangolensin was positively associated with plasma estradiol level (eta(p)(2) = 0.3%; P = 0.010). There were significant phytoestrogen interactions with polymorphisms in ESR1 and NR1I2 genes in affecting estrone levels. We conclude that phytoestrogens modulate sex hormone and SHBG levels in postmenopausal women and interact with gene variants involved in estrogen signaling. Such phytoestrogen-gene interactions may explain the conflicting literature on the hormonal effects of phytoestrogens.

The effects of soy extract on the uterus of castrated adult rats

OBJECTIVE

The aim of this study was to evaluate the effects of different doses of a standardized soy extract on the uterus of castrated rats.

METHODS

Fifty-six adult castrated female Wistar rats were randomly divided into seven groups (eight animals in each) that received: GI--drug vehicle (propylene glycol); GII--soy extract 10mg/kg per day; GIII--soy extract 50mg/kg per day; GIV--soy extract 100mg/kg per day; GV--soy extract 300mg/kg per day; GVI--soy extract 600mg/kg per day; GVII-conjugated equine estrogens (CEE) 200microg/kg per day. After 21 days of treatment, all animals were sacrificed and fragments of the uterine horns were immediately removed, fixed in 10% formaldehyde and submitted to routine histological techniques for morphometric study. The endometrial cell proliferation index was determined with the PCNA antibody PC-10 and expressed as the percentuals of the PCNA-positive nuclei relative to the total countings. Other fragments were immediately frozen in liquid nitrogen for RNA extraction and VEGF analysis using RT-PCR technique.

RESULTS

The minimal dose of soy extract that produced a significant increase of the morphometric parameters was 100mg/kg (GIV). The maximum effects on endometrial and myometrial morphometry were detected in the groups treated with 300 and 600mg/kg of soy extract (groups V and VI) and CEE (GVII). The expression of PCNA in the endometrial epithelium and stroma was increased by treatment with 100-600mg/kg per day of soy extract (groups IV-VI) or with CCE (group VII). Doses equal to or higher than 50mg/kg of soy extract (groups III-VI) and CEE stimulated the expression of VEGF.

CONCLUSION

The treatment of adult castrated rats during 21 days with doses of 100mg/kg per day or higher of soy extract may determine significant proliferation in the endometrium and myometrium.

Efficacy on menopausal neurovegetative symptoms and some plasma lipids blood levels of an herbal product containing isoflavones and other plant extracts

OBJECTIVES

To assess the efficacy of a product containing isoflavones and other plant extracts (BIO) on whole menopausal symptomatology and plasma lipids profile.

METHODS

Multicentre, randomized, double blind, placebo controlled clinical investigation on 125 menopausal women randomly assigned to two groups treated for 6 months with placebo or one tablet daily of an herbal product containing 72 mg/dose of isoflavones of different plants origin and other plant extracts (BIO). Primary end-point: Kupperman Menopause Index (KI) variations; secondary end-point: activity on plasma lipids profile and clinical global impression (CGI) on efficacy and tolerability by investigators and patients. The usual parametric test (paired Student t test) was performed to evaluate the significance. In case of non-applicability of parametric tests, the non-parametric Mann-Whitney U test was used. The differences where considered significant at p<0.05 level.

RESULTS

At the end of treatment in both groups KI showed a significant decrease (p<0.001). However, in the BIO group the KI reduction was significantly higher (p=0.0265) than in the placebo group after 4 and 6 months of treatment. In the BIO treated patients the LDL cholesterol showed a borderline but not significant reduction compared to placebo (p=0.0608) and triglyceride (TG) a significant (p=0.0151) decrease compared to placebo. The investigator's and patient's CGI on BIO group where superior as compared to placebo. Clinical tolerability was good in booth groups.

CONCLUSION

On the basis of positive effects on KI and lipids profile as well as of good clinical tolerability, BIO can be considered one of the possible alternative therapy for conventional HRT.

Effects of soy protein and resistance exercise on body composition and blood lipids in postmenopausal women

OBJECTIVE

To assess the effect of soy protein and progressive resistance training on body composition and lipids in postmenopausal women.

DESIGN

In a controlled trial, 46 postmenopausal women were randomized to one of four groups: 25 g of soy protein (SP, n=10), 25 g of soy protein plus resistance exercise (SPE, n=14), 25 g of maltodextrine (placebo) (PL, n=11), or placebo plus resistance exercise (PLE, n=11). Progressive resistance training was held three times a week for 16 weeks and included 8 exercises (3 series of 8-12 repetitions). At baseline and after 16 weeks, body mass index, waist circumference (WC), body fat, muscle mass and serum lipid levels were measured. To confirm isoflavone absorption, urinary concentrations were determined. The t-test of Student and ANOVA were used in the statistical analysis.

RESULTS

Subjects were classified as overweight and showed android fat distribution. Urinary isoflavone excretion indicated compliance to soy protein treatment. After 16 weeks of intervention, both SPE and PLE groups showed a significant increase of 1.3 kg in muscle mass and reduction in WC of -1.4 and -2.1cm, respectively (p<0.05). Significant decreases in the mean values of total cholesterol and LDL (-29.0 and -24.0 mg/dL, p<0.001 and p<0.006, respectively) were observed in the users of soy protein alone (SP).

CONCLUSIONS

Soy protein supplementation did not influence the indicators of body composition. However, it exerted possible favorable effects on lipid profile in postmenopausal women. The increase in muscle mass and reduction in abdominal fat were correlated with resistance training.

Isoflavone therapy for menopausal flushes: a systematic review and meta-analysis

OBJECTIVE

To perform a systematic review and meta-analysis of all randomized, controlled trials of isoflavone supplementation to determine the efficacy of isoflavone therapy in reducing the number of daily menopausal flushes.

METHODS

A comprehensive search of published studies of isoflavone treatment and menopausal flushing was undertaken. Studies were selected if they were randomized, were placebo controlled, provided the number of baseline flushes, the variance in flushes and the reduction in flushes. Effects for isoflavone treatment compared to control were calculated and a meta-analysis was performed. Regression analysis, weighted for the size of the study was performed to investigate the relationship between the dose of isoflavone, or number of baseline flushes and the reduction in flushes achieved compared to control.

RESULTS

Isoflavone supplementation was found to be associated with a significant reduction in flushes (effect size -0.28, 95% confidence intervals -0.39 to -0.18, P < 0.0001). Marked heterogeneity was found between the studies, but the effect remained significant when analyzed using a random effects model (delta = -0.49, 95% confidence intervals -0.81 to -0.17, P = 0.001). The percentage reduction in flushes was significantly related to the number of baseline flushes per day and the dose of isoflavone studied (beta = -0.49 and -0.26, respectively, both P < 0.0001).

CONCLUSIONS

These results suggest that isoflavone supplementation may produce a slight to modest reduction the number of daily flushes in menopausal women and that the benefit may be more apparent in women experiencing a high number of flushes per day.

Critical review of health effects of soyabean phyto-oestrogens in post-menopausal women

A consensus view of soyabean phyto-oestrogens in clinical interventions in post-menopausal women is presented that is based on data from the EU-funded project Phytohealth. The phyto-oestrogens, primarily genistein and daidzein, were given as soyabean-protein isolates, whole-soyabean foods or extracts, supplements or pure compounds. A comprehensive literature search was conducted with well-defined inclusion or exclusion criteria. For areas for which substantial research exists only placebo-controlled double-blind randomised controlled trials (RCT) conducted on healthy post-menopausal women were included. For emerging areas all available human studies in post-menopausal women were reviewed. In order to make cross comparisons between studies the doses of isoflavones were calculated as aglycone equivalents. There is a suggestion, but no conclusive evidence, that isoflavones from the sources studied so far have a beneficial effect on bone health. The consumption of whole-soyabean foods and soyabean-protein isolates has some beneficial effects on lipid markers of cardiovascular risk. The consumption of isolated isoflavones does not affect blood lipid levels or blood pressure, although it may improve endothelial function. For menopausal symptoms there is currently limited evidence that soyabean-protein isolates, soyabean foods or red-clover (Trifolium pratense L.) extract are effective but soyabean isoflavone extracts may be effective in reducing hot flushes. There are too few RCT studies to reach conclusions on the effects of isoflavones on breast cancer, colon cancer, diabetes or cognitive function. The health benefits of soyabean phyto-oestrogens in healthy post-menopausal women are subtle and even some well-designed studies do not show protective effects. Future studies should focus on high-risk post-menopausal women, especially in the areas of diabetes, CVD, breast cancer and bone health.

A Review of Non-Hormonal Options for the Relief of Menopausal Symptoms

The climacteric syndrome involves a variety of symptoms such as profuse sweating, insomnia, memory loss, decreased sexual drives, joint aches, and anxiety. However, amongst these symptoms, hot flashes and sweats are generally considered the hallmark and result in the majority of the medical consultations for this condition. Hot flashes are known to respond readily to placebo, which alone decreases their frequency by 20-40%. In the ideal setting of clinical trials, with optimal patient selection and compliance, estrogen therapy reduces hot flashes by about 70-80%; this is twice as effective as placebo. However, estrogen is unable to be universally used, either because of contraindications or because of an unwillingness of women to take it. Furthermore, hot flashes may persist in spite of adequate estrogen replacement, and physicians are often faced with the dilemma of finding something to administer in place of, or in addition to, estrogen to improve symptoms. The most commonly used non-hormonal alternatives for climacteric symptoms are neurotransmitter modulators such as serotonin reuptake inhibitors and gabapentin. These are, at best, approximately half as effective as estrogen for the relief of menopausal symptoms, and are only marginally better than placebo.Complementary treatment, particularly over-the-counter phytotherapeutic extracts, are very popular and women often try a variety of such products before resorting to conventional medicine. Preparations containing isoflavones, such as soy extract and red clover or extracts from evening primrose or cimicifuga (black cohosh, Actaea racemosa, syn. Cimicifuga racemosa), in variable doses are very popular for the treatment of hot flashes. The scientific support for their efficacy certainly does not equal their popularity.Non-hormonal treatments for menopause are not as effective as estrogens in relieving hot flashes, but may have a role in therapy for women who have contraindications to gonadal steroid use.