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Hüser S, Guth S, Joost HG, Soukup ST, Köhrle J, Kreienbrock L, Diel P, Lachenmeier DW, Eisenbrand G, Vollmer G, Nöthlings U, Marko D, Mally A, Grune T, Lehmann L, Steinberg P, Kulling SE. Effects of isoflavones on breast tissue and the thyroid hormone system in humans: a comprehensive safety evaluation. Arch Toxicol 2018; 92:2703-2748. [PMID: 30132047 PMCID: PMC6132702 DOI: 10.1007/s00204-018-2279-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Accepted: 07/31/2018] [Indexed: 02/06/2023]
Abstract
Isoflavones are secondary plant constituents of certain foods and feeds such as soy, linseeds, and red clover. Furthermore, isoflavone-containing preparations are marketed as food supplements and so-called dietary food for special medical purposes to alleviate health complaints of peri- and postmenopausal women. Based on the bioactivity of isoflavones, especially their hormonal properties, there is an ongoing discussion regarding their potential adverse effects on human health. This review evaluates and summarises the evidence from interventional and observational studies addressing potential unintended effects of isoflavones on the female breast in healthy women as well as in breast cancer patients and on the thyroid hormone system. In addition, evidence from animal and in vitro studies considered relevant in this context was taken into account along with their strengths and limitations. Key factors influencing the biological effects of isoflavones, e.g., bioavailability, plasma and tissue concentrations, metabolism, temporality (pre- vs. postmenopausal women), and duration of isoflavone exposure, were also addressed. Final conclusions on the safety of isoflavones are guided by the aim of precautionary consumer protection.
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Affiliation(s)
- S Hüser
- Institute for Food Toxicology, Senate Commission on Food Safety, University of Veterinary Medicine Hannover, Hannover, Germany
| | - S Guth
- Institute for Food Toxicology, Senate Commission on Food Safety, University of Veterinary Medicine Hannover, Hannover, Germany
| | - H G Joost
- Department of Experimental Diabetology, German Institute of Human Nutrition (DIfE), Nuthetal, Germany
| | - S T Soukup
- Department of Safety and Quality of Fruit and Vegetables, Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Haid-und-Neu-Str. 9, 76131, Karlsruhe, Germany
| | - J Köhrle
- Institut für Experimentelle Endokrinologie, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, CVK, Berlin, Germany
| | - L Kreienbrock
- Department of Biometry, Epidemiology and Information Processing, University of Veterinary Medicine Hannover, Hannover, Germany
| | - P Diel
- Department of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, Cologne, Germany
| | - D W Lachenmeier
- Chemisches und Veterinäruntersuchungsamt Karlsruhe, Karlsruhe, Germany
| | - G Eisenbrand
- Division of Food Chemistry and Toxicology, Molecular Nutrition, Department of Chemistry, Technische Universität Kaiserslautern, Kaiserslautern, Germany
| | - G Vollmer
- Department of Biology, Molecular Cell Physiology and Endocrinology, Technische Universität Dresden, Dresden, Germany
| | - U Nöthlings
- Department of Nutrition and Food Sciences, Nutritional Epidemiology, Rheinische Friedrich-Wilhelms University Bonn, Bonn, Germany
| | - D Marko
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - A Mally
- Department of Toxicology, University of Würzburg, Würzburg, Germany
| | - T Grune
- Department of Molecular Toxicology, German Institute of Human Nutrition (DIfE), Nuthetal, Germany
| | - L Lehmann
- Department of Food Chemistry, Institute for Pharmacy and Food Chemistry, University of Würzburg, Würzburg, Germany
| | - P Steinberg
- Institute for Food Toxicology, University of Veterinary Medicine Hannover, Hannover, Germany
- Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Haid-und-Neu-Str. 9, 76131, Karlsruhe, Germany
| | - S E Kulling
- Department of Safety and Quality of Fruit and Vegetables, Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Haid-und-Neu-Str. 9, 76131, Karlsruhe, Germany.
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Anandhi Senthilkumar H, Fata JE, Kennelly EJ. Phytoestrogens: The current state of research emphasizing breast pathophysiology. Phytother Res 2018; 32:1707-1719. [DOI: 10.1002/ptr.6115] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 04/17/2018] [Accepted: 04/20/2018] [Indexed: 01/08/2023]
Affiliation(s)
- Harini Anandhi Senthilkumar
- Department of Biological Sciences, Lehman College; City University of New York; Bronx New York NY 10468 USA
- Biochemistry and Biology Ph.D. Programs, The Graduate Center; City University of New York; New York NY 10016 USA
| | - Jimmie E. Fata
- Biochemistry and Biology Ph.D. Programs, The Graduate Center; City University of New York; New York NY 10016 USA
- Department of Biological Sciences; College of Staten Island; Staten Island New York NY 10314 USA
| | - Edward J. Kennelly
- Department of Biological Sciences, Lehman College; City University of New York; Bronx New York NY 10468 USA
- Biochemistry and Biology Ph.D. Programs, The Graduate Center; City University of New York; New York NY 10016 USA
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van der Velpen V, van 't Veer P, Islam MA, Ter Braak CJF, van Leeuwen FXR, Afman LA, Hollman PC, Schouten EG, Geelen A. A risk assessment-driven quantitative comparison of gene expression profiles in PBMCs and white adipose tissue of humans and rats after isoflavone supplementation. Food Chem Toxicol 2016; 95:203-10. [PMID: 27424125 DOI: 10.1016/j.fct.2016.07.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 07/08/2016] [Accepted: 07/12/2016] [Indexed: 12/15/2022]
Abstract
Quantitative insight into species differences in risk assessment is expected to reduce uncertainty and variability related to extrapolation from animals to humans. This paper explores quantification and comparison of gene expression data between tissues and species from intervention studies with isoflavones. Gene expression data from peripheral blood mononuclear cells (PBMCs) and white adipose tissue (WAT) after 8wk isoflavone interventions in postmenopausal women and ovariectomized F344 rats were used. A multivariate model was applied to quantify gene expression effects, which showed 3-5-fold larger effect sizes in rats compared to humans. For estrogen responsive genes, a 5-fold greater effect size was found in rats than in humans. For these genes, intertissue correlations (r = 0.23 in humans, r = 0.22 in rats) and interspecies correlation in WAT (r = 0.31) were statistically significant. Effect sizes, intertissue and interspecies correlations for some groups of genes within energy metabolism, inflammation and cell cycle processes were significant, but weak. Quantification of gene expression data reveals differences between rats and women in effect magnitude after isoflavone supplementation. For risk assessment, quantification of gene expression data and subsequent calculation of intertissue and interspecies correlations within biological pathways will further strengthen knowledge on comparability between tissues and species.
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Affiliation(s)
- Vera van der Velpen
- Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands.
| | - Pieter van 't Veer
- Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands
| | - M Ariful Islam
- Sub-Department of Toxicology, Wageningen University, Wageningen, The Netherlands
| | - C J F Ter Braak
- Biometris, Wageningen University, Wageningen, The Netherlands
| | | | - Lydia A Afman
- Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands
| | - Peter C Hollman
- Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands; RIKILT Wageningen UR, Wageningen, The Netherlands
| | - Evert G Schouten
- Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands
| | - Anouk Geelen
- Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands
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Soy Isoflavones for Reducing Bone Loss Study: effects of a 3-year trial on hormones, adverse events, and endometrial thickness in postmenopausal women. Menopause 2016; 22:185-97. [PMID: 25003624 DOI: 10.1097/gme.0000000000000280] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE This study aims to assess the overall safety and potential endometrium-stimulating effects of soy isoflavone tablets consumed (3 y) by postmenopausal women and to determine endometrial thickness response to treatment among compliant women, taking into account hormone concentrations and other hypothesized modifying factors. METHODS We randomized healthy postmenopausal women (aged 45.8-65.0 y) to placebo control or two doses (80 or 120 mg/d) of soy isoflavones at two sites. We used intent-to-treat analysis (N = 224) and compliant analysis (>95%; N = 208) to assess circulating hormone concentrations, adverse events, and endometrial thickness (via transvaginal ultrasound). RESULTS Median values for endometrial thickness (mm) declined from baseline through 36 months. Nonparametric analysis of variance for treatment differences among groups showed no differences in absolute (or percentage of change) endometrial thickness (χ(2) P ranged from 0.12 to 0.69) or in circulating hormones at any time point. A greater number of adverse events in the genitourinary system (P = 0.005) were noted in the 80 mg/day group compared with the 120 mg/day group, whereas other systems showed no treatment effects. The model predicting endometrial thickness response (using natural logarithm) to treatment among compliant women across time points was significant (P ≤ 0.0001), indicating that estrogen exposure (P = 0.0013), plasma 17β-estradiol (P = 0.0086), and alcohol intake (P = 0.023) contributed significantly to the response. Neither the 80 mg/day dose (P = 0.57) nor the 120 mg/day dose (P = 0.43) exerted an effect on endometrial thickness across time. CONCLUSIONS Our randomized controlled trial verifies the long-term overall safety of soy isoflavone tablet intake by postmenopausal women who display excellent compliance. We find no evidence of treatment effects on endometrial thickness, adverse events, or circulating hormone concentrations, most notably thyroid function, across a 3-year period.
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Lethaby A, Marjoribanks J, Kronenberg F, Roberts H, Eden J, Brown J. Phytoestrogens for menopausal vasomotor symptoms. Cochrane Database Syst Rev 2013; 2013:CD001395. [PMID: 24323914 PMCID: PMC10247921 DOI: 10.1002/14651858.cd001395.pub4] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
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.
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Affiliation(s)
- Anne Lethaby
- University of AucklandDepartment of Obstetrics and GynaecologyPrivate Bag 92019AucklandNew Zealand1142
| | - Jane Marjoribanks
- University of AucklandDepartment of Obstetrics and GynaecologyPrivate Bag 92019AucklandNew Zealand1142
| | - Fredi Kronenberg
- College of Physicians & Surgeons, Columbia University in the City of New YorkDepartment of Rehabilitation MedicineBOX 75630 W 168TH STNew YorkUSANY 10027‐6902
| | - Helen Roberts
- University of AucklandDepartment of Obstetrics and GynaecologyPrivate Bag 92019AucklandNew Zealand1142
| | - John Eden
- Royal Hospital for WomenSydney Menopause Centre & Natural Therapies UnitLocked Bag 2000RandwickNSWAustralia2031
| | - Julie Brown
- University of AucklandThe Liggins Institute and Department of Obstetrics and GynaecologyFMHSAucklandNew Zealand
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Fritz H, Seely D, Flower G, Skidmore B, Fernandes R, Vadeboncoeur S, Kennedy D, Cooley K, Wong R, Sagar S, Sabri E, Fergusson D. Soy, red clover, and isoflavones and breast cancer: a systematic review. PLoS One 2013; 8:e81968. [PMID: 24312387 PMCID: PMC3842968 DOI: 10.1371/journal.pone.0081968] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 10/18/2013] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Soy and red clover isoflavones are controversial due to purported estrogenic activity and possible effects on breast cancer. We conducted a systematic review of soy and red clover for efficacy in improving menopausal symptoms in women with breast cancer, and for potential impact on risk of breast cancer incidence or recurrence. METHODS We searched MEDLINE, Embase, the Cochrane Library, and AMED from inception to March 2013 for human interventional or observational data pertaining to the safety and efficacy of soy and red clover isoflavones in patients with or at risk of breast cancer. RESULTS Of 4179 records, we included a total of 131 articles: 40 RCTs, 11 uncontrolled trials, and 80 observational studies. Five RCTs reported on the efficacy of soy for hot flashes, showing no significant reductions in hot flashes compared to placebo. There is lack of evidence showing harm from use of soy with respect to risk of breast cancer or recurrence, based on long term observational data. Soy intake consistent with that of a traditional Japanese diet (2-3 servings daily, containing 25-50mg isoflavones) may be protective against breast cancer and recurrence. Human trials show that soy does not increase circulating estradiol or affect estrogen-responsive target tissues. Prospective data of soy use in women taking tamoxifen does not indicate increased risk of recurrence. Evidence on red clover is limited, however existing studies suggest that it may not possess breast cancer-promoting effects. CONCLUSION Soy consumption may be associated with reduced risk of breast cancer incidence, recurrence, and mortality. Soy does not have estrogenic effects in humans. Soy intake consistent with a traditional Japanese diet appears safe for breast cancer survivors. While there is no clear evidence of harm, better evidence confirming safety is required before use of high dose (≥ 100 mg) isoflavones can be recommended for breast cancer patients.
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Affiliation(s)
- Heidi Fritz
- Department of Research & Clinical Epidemiology, Canadian College of Naturopathic Medicine, Toronto, Ontario, Canada
| | - Dugald Seely
- Department of Research & Clinical Epidemiology, Canadian College of Naturopathic Medicine, Toronto, Ontario, Canada
- Clinical Epidemiology, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
- Ottawa Integrative Cancer Center, Ottawa, Ontario, Canada
| | - Gillian Flower
- Department of Research & Clinical Epidemiology, Canadian College of Naturopathic Medicine, Toronto, Ontario, Canada
| | - Becky Skidmore
- Clinical Epidemiology, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Rochelle Fernandes
- Department of Research & Clinical Epidemiology, Canadian College of Naturopathic Medicine, Toronto, Ontario, Canada
- Laboratory Medicine and Pathobiology (LMP), University of Toronto, Toronto, Ontario, Canada
| | - Sarah Vadeboncoeur
- Department of Research & Clinical Epidemiology, Canadian College of Naturopathic Medicine, Toronto, Ontario, Canada
| | - Deborah Kennedy
- Department of Research & Clinical Epidemiology, Canadian College of Naturopathic Medicine, Toronto, Ontario, Canada
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Kieran Cooley
- Department of Research & Clinical Epidemiology, Canadian College of Naturopathic Medicine, Toronto, Ontario, Canada
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Raimond Wong
- Juravinski Cancer Centre and Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Stephen Sagar
- Juravinski Cancer Centre and Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Elham Sabri
- Clinical Epidemiology, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Dean Fergusson
- Clinical Epidemiology, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
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Delmanto A, Nahas-Neto J, Traiman P, Uemura G, Pessoa EC, Nahas EAP. Effects of soy isoflavones on mammographic density and breast parenchyma in postmenopausal women: a randomized, double-blind, placebo-controlled clinical trial. Menopause 2013; 20:1049-54. [PMID: 23481125 DOI: 10.1097/gme.0b013e3182850270] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
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.
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Affiliation(s)
- Armando Delmanto
- From the Department of Gynecology and Obstetrics, Botucatu Medical School, São Paulo State University (UNESP), São Paulo, Brazil
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Hernandez-Elizondo J, Monteagudo C, Murcia MA, Olea N, Olea-Serrano F, Mariscal-Arcas M. Assessment of the estrogenicity of the diet of a healthy female Spanish population based on its isoflavone content. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2013; 30:627-33. [PMID: 23506255 DOI: 10.1080/19440049.2013.775604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Phytoestrogens are natural components of plants consumed by humans. The hormonal activity of these substances has long been known. Various in vitro tests have demonstrated the agonistic or antagonistic estrogenic activity of some phytoestrogens. The objective of this study was to estimate the supply of isoflavones in the diet of a healthy adult female population and to assess its estrogenic effect. The diet was assessed by questionnaire and the estrogenicity of the estimated isoflavone content was tested by E-screen, finding a mean total estrogenic capacity of 0.129 × 10⁻¹⁰ eq.E₂ (12.9 pmol day⁻¹), corresponding to a daily isoflavone intake of 265.8 μg day⁻¹. This study offers a preliminary insight into the phytoestrogen content of the diet of a healthy active population of Spanish women. The effects of this additional hormonal burden are highly controversial, and this approach to estimating dietary phytoestrogen intake of specific populations may help to elucidate its implications for human health.
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Affiliation(s)
- J Hernandez-Elizondo
- Research Group on Nutrition, Diet and Risk Assessment-AGR255, Department of Nutrition and Food Science, University of Granada, Granada, Spain
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Abstract
OBJECTIVE To review the evidence that isoflavones are effective treatments for menopausal symptoms and to present the safety data. METHODS The databases Scopus, ScienceDirect and Primo Central Index were searched and preference was given to systematic reviews and meta-analyses. RESULTS The available evidence suggests that isoflavones do not relieve menopausal vasomotor symptoms any better than placebo. Long-term safety studies suggest that women who consume a diet high in isoflavones may have a lower risk of endometrial and ovarian cancer. CONCLUSIONS Isoflavones cannot be recommended for the relief of hot flushes.
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Villaseca P. Non-estrogen conventional and phytochemical treatments for vasomotor symptoms: what needs to be known for practice. Climacteric 2011; 15:115-24. [PMID: 22148909 DOI: 10.3109/13697137.2011.624214] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Non-hormonal treatment for menopausal vasomotor symptoms (VMS) is needed in women in whom there are medical or personal concerns on the use of hormone therapy. This paper reviews conventional and phytochemical therapies available for the relief of VMS, on their mechanisms of action, their efficacy and safety concerns. METHODS Medline was searched through Pubmed on the names of the diverse therapies analyzed, up to June 2011. The Cochrane Controlled Clinical Trials Register Database was searched for relevant trials that provided data on treatment of menopausal hot flushes. RESULTS All non-estrogen treatments for VMS are less efficacious than estrogen treatment. Randomized trials with neuroendocrine agents show globally modest to moderate reduction of VMS and frequent bothersome adverse events. The variability of effects makes it possible to undergo treatment in search for individual response where estrogen treatment is contraindicated. The antidepressants that interact with cytochrome P450, inhibiting tamoxifen metabolism to endoxifen, interfere with tamoxifen therapy in breast cancer patients. Otherwise, botanical products containing isoflavones from soy bean or red clover have great variability in bioavailability, have a broader spectrum of action than estradiol, and have predominant estrogen receptor-b activity. The efficacy of phytoestrogens on VMS is similar to placebo. They should be avoided in women with breast cancer and, in particular, in women being treated with tamoxifen or aromatase inhibitors due to possible antagonism. Cimicifuga racemosa is not a phytoestrogen, has partial serotonin agonist action and has a modest effect on VMS. CONCLUSIONS There are safe non-hormonal conventional treatments for menopausal VMS, although they are less efficacious than estrogens. The indication of phytochemicals is for women who make this choice on personal beliefs; long-term studies of larger groups of patients are needed to assess safety.
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Affiliation(s)
- P Villaseca
- Departamento de Endocrinología, Pontificia Universidad Católica de Chile, Endocrinología, Lira 85, Santiago, Chile
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Ferraz Carbonel AA, Simões RS, Rabelo Santos RHB, Pinheiro Baracat MC, Jesus Simões MD, Baracat EC, Soares Júnior JM. Efeitos das isoflavonas em altas doses sobre o útero da rata. Rev Assoc Med Bras (1992) 2011; 57:534-9. [DOI: 10.1590/s0104-42302011000500011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 06/27/2011] [Indexed: 11/21/2022] Open
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12
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Effects of high-dose isoflavones on rat uterus. Rev Assoc Med Bras (1992) 2011. [DOI: 10.1016/s0104-4230(11)70107-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Abstract
A high intake of fruits and vegetables is associated with a lower risk of cancer. In this context, considerable attention is paid to Asian populations who consume high amounts of soy and soy-derived isoflavones, and have a lower risk for several cancer types such as breast and prostate cancers than populations in Western countries. Hence, interest focuses on soyfoods, soy products, and soy ingredients such as isoflavones with regard to their possible beneficial effects that were observed in numerous experiments and studies. The outcomes of the studies are not always conclusive, are often contradictory depending on the experimental conditions, and are, therefore, difficult to interpret. Isoflavone research revealed not only beneficial but also adverse effects, for instance, on the reproductive system. This is also the case with tumor-promoting effects on, for example, breast tissue. Isoflavone extracts and supplements are often used for the treatment of menopausal symptoms and for the prevention of age-associated conditions such as cardiovascular diseases and osteoporosis in postmenopausal women. In relation to this, questions about the effectiveness and safety of isoflavones have to be clarified. Moreover, there are concerns about the maternal consumption of isoflavones due to the development of leukemia in infants. In contrast, men may benefit from the intake of isoflavones with regard to reducing the risk of prostate cancer. Therefore, this review examines the risks but also the benefits of isoflavones with regard to various kinds of cancer, which can be derived from animal and human studies as well as from in vitro experiments.
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Affiliation(s)
- Susanne Andres
- Department of Food Safety, Federal Institute for Risk Assessment, Berlin, Germany
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14
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Bondesson M, Gustafsson JA. Does consuming isoflavones reduce or increase breast cancer risk? Genome Med 2010; 2:90. [PMID: 21176178 PMCID: PMC3025432 DOI: 10.1186/gm211] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Epidemiological studies suggest that consumption of phytoestrogens, in particular isoflavones, correlates with a lower incidence of breast cancer. However, data from human intervention studies have been less clear. Several meta-analyses have reported beneficial but relatively weak effects of isoflavone consumption on reduction of hot flushes and osteoporosis and improvement of cholesterol levels. However, the effects of isoflavones on early breast cancer markers differ between pre- and post-menopausal women. Conclusions on whether exposure of animals (mice and rats) to isoflavones protects against or promotes breast cancer development and growth vary between different studies. These results, taken together with the heterogeneous outcomes of human interventions, have led to a controversy surrounding the intake of isoflavone to reduce breast cancer risk. Here, we describe the results of recent human and animal intervention studies and discuss factors that might explain the variation in results. We also describe possible molecular mechanisms of action of isoflavones; distinguishing which mechanism(s) are involved is needed if we are to solve the controversy surrounding the actions of these compounds.
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Affiliation(s)
- Maria Bondesson
- Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, TX 77204, USA.
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