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Ruiz-Saavedra S, Zapico A, González S, Salazar N, de los Reyes-Gavilán CG. Role of the intestinal microbiota and diet in the onset and progression of colorectal and breast cancers and the interconnection between both types of tumours. MICROBIOME RESEARCH REPORTS 2023; 3:6. [PMID: 38455079 PMCID: PMC10917624 DOI: 10.20517/mrr.2023.36] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 11/12/2023] [Accepted: 11/21/2023] [Indexed: 03/09/2024]
Abstract
Colorectal cancer (CRC) is among the leading causes of mortality in adults of both sexes worldwide, while breast cancer (BC) is among the leading causes of death in women. In addition to age, gender, and genetic predisposition, environmental and lifestyle factors exert a strong influence. Global diet, including alcohol consumption, is one of the most important modifiable factors affecting the risk of CRC and BC. Western dietary patterns promoting high intakes of xenobiotics from food processing and ethanol have been associated with increased cancer risk, whereas the Mediterranean diet, generally leading to a higher intake of polyphenols and fibre, has been associated with a protective effect. Gut dysbiosis is a common feature in CRC, where the usual microbiota is progressively replaced by opportunistic pathogens and the gut metabolome is altered. The relationship between microbiota and BC has been less studied. The estrobolome is the collection of genes from intestinal bacteria that can metabolize oestrogens. In a dysbiosis condition, microbial deconjugating enzymes can reactivate conjugated-deactivated oestrogens, increasing the risk of BC. In contrast, intestinal microorganisms can increase the biological activity and bioavailability of dietary phytochemicals through diverse microbial metabolic transformations, potentiating their anticancer activity. Members of the intestinal microbiota can increase the toxicity of xenobiotics through metabolic transformations. However, most of the microorganisms involved in diet-microbiota interactions remain poorly characterized. Here, we provide an overview of the associations between microbiota and diet in BC and CRC, considering the diverse types and heterogeneity of these cancers and their relationship between them and with gut microbiota.
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Affiliation(s)
- Sergio Ruiz-Saavedra
- Department of Microbiology and Biochemistry of Dairy Products, Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Villaviciosa 33300, Spain
- Diet, Microbiota and Health Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo 33011, Spain
| | - Aida Zapico
- Diet, Microbiota and Health Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo 33011, Spain
- Department of Functional Biology, University of Oviedo, Oviedo 33006, Spain
| | - Sonia González
- Diet, Microbiota and Health Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo 33011, Spain
- Department of Functional Biology, University of Oviedo, Oviedo 33006, Spain
| | - Nuria Salazar
- Department of Microbiology and Biochemistry of Dairy Products, Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Villaviciosa 33300, Spain
- Diet, Microbiota and Health Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo 33011, Spain
| | - Clara G. de los Reyes-Gavilán
- Department of Microbiology and Biochemistry of Dairy Products, Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Villaviciosa 33300, Spain
- Diet, Microbiota and Health Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo 33011, Spain
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Rajaram N, Yap B, Eriksson M, Mariapun S, Tan LM, Sa’at H, Ho ELM, Taib NAM, Khor GL, Yip CH, Ho WK, Hall P, Teo SH. A Randomized Controlled Trial of Soy Isoflavone Intake on Mammographic Density among Malaysian Women. Nutrients 2023; 15:nu15020299. [PMID: 36678170 PMCID: PMC9862880 DOI: 10.3390/nu15020299] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/19/2022] [Accepted: 01/03/2023] [Indexed: 01/11/2023] Open
Abstract
Soy intake is associated with lower breast cancer risk in observational studies concerning Asian women, however, no randomized controlled trials (RCT) have been conducted among Asian women living in Asia. This three-armed RCT assessed the effects of one-year soy isoflavone (ISF) intervention on mammographic density (MD) change among healthy peri- and postmenopausal Malaysian women. This study was registered at ClinicalTrials.gov (NCT03686098). Participants were randomized into the 100 mg/day ISF Supplement, 50 mg/day ISF Diet, or control arm, and assessed for change in absolute and relative dense area from digital mammograms conducted at enrolment and after 12 months, compared over time across study arms using Kruskal-Wallis tests. Out of 118 women enrolled, 91 women completed the intervention, while 27 women (23%) were lost in follow up. The ISF supplement arm participants observed a larger decline in dense area (−1.3 cm2), compared to the ISF diet (−0.5 cm2) and control arm (−0.8 cm2), though it was not statistically significant (p = 0.48). Notably, among women enrolled within 5 years of menopause; dense area declined by 6 cm2 in the ISF supplement arm, compared to <1.0 cm2 in the control arm (p = 0.13). This RCT demonstrates a possible causal association between soy ISF intake and MD, a biomarker of breast cancer risk, among Asian women around the time of menopause, but these findings require confirmation in a larger trial.
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Affiliation(s)
- Nadia Rajaram
- Cancer Research Malaysia, Subang Jaya 47500, Malaysia
| | - Beverley Yap
- Cancer Research Malaysia, Subang Jaya 47500, Malaysia
| | | | | | - Lee Mei Tan
- Cancer Research Malaysia, Subang Jaya 47500, Malaysia
| | - Hamizah Sa’at
- University of Malaya Cancer Research Institute, Kuala Lumpur 50603, Malaysia
| | - Evelyn Lai Ming Ho
- ParkCity Medical Centre, Ramsay Sime Darby Healthcare, Kuala Lumpur 52200, Malaysia
| | | | - Geok Lin Khor
- Department of Nutrition and Dietetics, Universiti Putra Malaysia, Serdang 43400, Malaysia
| | - Cheng Har Yip
- Cancer Research Malaysia, Subang Jaya 47500, Malaysia
- Subang Jaya Medical Centre, Ramsay Sime Darby Healthcare, Subang Jaya 47500, Malaysia
| | - Weang Kee Ho
- Cancer Research Malaysia, Subang Jaya 47500, Malaysia
- Department of Applied Mathematics, Faculty of Engineering, University of Nottingham Malaysia, Semenyih 43500, Malaysia
| | - Per Hall
- Karolinska Institutet, 171 77 Stockholm, Sweden
- Södersjukhuset, 118 83 Stockholm, Sweden
| | - Soo Hwang Teo
- Cancer Research Malaysia, Subang Jaya 47500, Malaysia
- University of Malaya Cancer Research Institute, Kuala Lumpur 50603, Malaysia
- Correspondence: ; Tel.: +60-356-509-797
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Ohishi T, Miyoshi N, Mori M, Sagara M, Yamori Y. Health Effects of Soy Isoflavones and Green Tea Catechins on Cancer and Cardiovascular Diseases Based on Urinary Biomarker Levels. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27248899. [PMID: 36558031 PMCID: PMC9781513 DOI: 10.3390/molecules27248899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 12/07/2022] [Accepted: 12/09/2022] [Indexed: 12/23/2022]
Abstract
Plant polyphenols have various health effects. Genistein, which is abundant in soybeans, and epigallocatechin-3-gallate, which is abundant in green tea, are major flavonoids, a subclass group of polyphenols. Several epidemiological studies have shown that these flavonoids have beneficial effects against cancer and cardiovascular diseases. However, other studies did not show such effects. Several confounding factors, including recall bias, are related to these inconsistent findings, and the determination of metabolites in the urine may be useful in reducing the number of confounding factors. Equipment, which can be used by research participants to collect samples from a portion of voided urine within 24 h without the help of medical workers, has been developed for epidemiological investigations. Previous studies, in which flavonoid metabolites in these urine samples were measured, revealed that soy intake was correlated with a reduced risk of certain types of cancer and cardiovascular diseases worldwide. Although soybeans and green tea consumption may have protective effects against cancer and cardiovascular diseases, further clinical studies that consider different confounding factors are required to provide evidence for the actual impact of dietary flavonoids on human diseases, including cancer and cardiovascular diseases. One possible mechanism involved is discussed in relation to the downregulation of reactive oxygen species and the upregulation of 5'-adenosine monophosphate-activated protein kinase elicited by these flavonoids.
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Affiliation(s)
- Tomokazu Ohishi
- Institute of Microbial Chemistry (BIKAKEN), Numazu, Microbial Chemistry Research Foundation, Shizuoka 410-0301, Japan
- Laboratory of Oncology, Institute of Microbial Chemistry (BIKAKEN), Microbial Chemistry Research Foundation, Tokyo 141-0021, Japan
- Correspondence: (T.O.); (Y.Y.)
| | - Noriyuki Miyoshi
- Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
| | - Mari Mori
- Department of Health Management, School of Health Studies, Tokai University, Kanagawa 259-1292, Japan
- NPO World Health Frontier Institute, Nishinomiya 663-8143, Japan
- Institute for World Health Development, Mukogawa Women’s University, Nishinomiya 663-8143, Japan
| | - Miki Sagara
- Institute for World Health Development, Mukogawa Women’s University, Nishinomiya 663-8143, Japan
- Disease Model Cooperative Research Association, Kyoto 606-0805, Japan
| | - Yukio Yamori
- Institute for World Health Development, Mukogawa Women’s University, Nishinomiya 663-8143, Japan
- Correspondence: (T.O.); (Y.Y.)
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Mayo B, Vázquez L, Flórez AB. Equol: A Bacterial Metabolite from The Daidzein Isoflavone and Its Presumed Beneficial Health Effects. Nutrients 2019; 11:nu11092231. [PMID: 31527435 PMCID: PMC6770660 DOI: 10.3390/nu11092231] [Citation(s) in RCA: 188] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 09/05/2019] [Accepted: 09/11/2019] [Indexed: 12/11/2022] Open
Abstract
Epidemiological data suggest that regular intake of isoflavones from soy reduces the incidence of estrogen-dependent and aging-associated disorders, such as menopause symptoms in women, osteoporosis, cardiovascular diseases and cancer. Equol, produced from daidzein, is the isoflavone-derived metabolite with the greatest estrogenic and antioxidant activity. Consequently, equol has been endorsed as having many beneficial effects on human health. The conversion of daidzein into equol takes place in the intestine via the action of reductase enzymes belonging to incompletely characterized members of the gut microbiota. While all animal species analyzed so far produce equol, only between one third and one half of human subjects (depending on the community) are able to do so, ostensibly those that harbor equol-producing microbes. Conceivably, these subjects might be the only ones who can fully benefit from soy or isoflavone consumption. This review summarizes current knowledge on the microorganisms involved in, the genetic background to, and the biochemical pathways of, equol biosynthesis. It also outlines the results of recent clinical trials and meta-analyses on the effects of equol on different areas of human health and discusses briefly its presumptive mode of action.
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Affiliation(s)
- Baltasar Mayo
- Departamento de Microbiología y Bioquímica, Instituto de Productos Lácteos de Asturias (IPLA), Consejo Superior de Investigaciones Científicas (CSIC), Paseo Río Linares s/n, 33300 Villaviciosa, Spain.
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Avenida de Roma s/n, 33011 Oviedo, Spain.
| | - Lucía Vázquez
- Departamento de Microbiología y Bioquímica, Instituto de Productos Lácteos de Asturias (IPLA), Consejo Superior de Investigaciones Científicas (CSIC), Paseo Río Linares s/n, 33300 Villaviciosa, Spain.
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Avenida de Roma s/n, 33011 Oviedo, Spain.
| | - Ana Belén Flórez
- Departamento de Microbiología y Bioquímica, Instituto de Productos Lácteos de Asturias (IPLA), Consejo Superior de Investigaciones Científicas (CSIC), Paseo Río Linares s/n, 33300 Villaviciosa, Spain.
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Avenida de Roma s/n, 33011 Oviedo, Spain.
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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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Atkinson C, Ray RM, Li W, Lin MG, Gao DL, Shannon J, Stalsberg H, Porter PL, Frankenfeld CL, Wähälä K, Thomas DB, Lampe JW. Plasma equol concentration is not associated with breast cancer and fibrocystic breast conditions among women in Shanghai, China. Nutr Res 2016; 36:863-71. [PMID: 27440541 DOI: 10.1016/j.nutres.2016.03.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 03/22/2016] [Accepted: 03/23/2016] [Indexed: 01/12/2023]
Abstract
Equol (a bacterial metabolite of the soy isoflavone daidzein) is produced by 30% to 50% of humans and may be associated with health outcomes. We hypothesized that plasma equol would be inversely associated with risks of fibrocystic breast conditions (FBC) and breast cancer (BC). Plasma from women in a breast self-examination trial in Shanghai with BC (n=269) or FBC (n=443), and age-matched controls (n=1027) was analyzed for isoflavones. Equol was grouped into categories (<20, 20-<45, and ≥45nmol/L) and, among women with daidzein ≥20nmol/L, the log10 equol:daidzein ratio was grouped into tertiles. Where available, non-cancerous tissue (NCT) adjacent to the carcinomas from women with BC were classified as non-proliferative or proliferative (n=130 and 172, respectively). The lesions from women with FBC were similarly classified (n=99 and 92, respectively). Odds ratios (OR) and 95% confidence intervals (CI) were calculated across equol categories and tertiles of log10 equol:daidzein ratio. Equol categories were not associated with FBC or BC (P>.05). For log10 equol:daidzein, compared to controls there were positive associations in the mid tertile for proliferative FBC (OR 2.06, 95% CI 1.08-3.93), BC with proliferative NCT (OR 2.95, 95% CI 1.37-6.35), and all BC regardless of histology (OR 2.37, 95% CI 1.43-3.95). However, trends in ORs with increasing plasma equol values or equol:daidzein ratios were not observed (P>.05). The results of this study do not provide evidence that equol plays a role in the etiology of these breast conditions. However, further work is needed to confirm or refute this conclusion.
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Affiliation(s)
- Charlotte Atkinson
- Bristol Dental School, University of Bristol, Bristol, UK; NIHR Biomedical Research Unit in Nutrition, Diet, and Lifestyle, University Hospitals Bristol NHS Foundation Trust and University of Bristol, Bristol, UK.
| | - Roberta M Ray
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Wenjin Li
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Ming-Gang Lin
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Dao Li Gao
- Zhong Shan Hospital Cancer Center, Shanghai, China
| | | | | | - Peggy L Porter
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | | | | | - David B Thomas
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA
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Ko KP, Kim CS, Ahn Y, Park SJ, Kim YJ, Park JK, Lim YK, Yoo KY, Kim SS. Plasma isoflavone concentration is associated with decreased risk of type 2 diabetes in Korean women but not men: results from the Korean Genome and Epidemiology Study. Diabetologia 2015; 58:726-35. [PMID: 25533387 DOI: 10.1007/s00125-014-3463-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 11/05/2014] [Indexed: 01/03/2023]
Abstract
AIMS/HYPOTHESIS To examine the association between soybean products and risk of type 2 diabetes, we measured four isoflavone biological markers--genistein, daidzein, glycitein and equol--in a nested case-control study. METHODS The study population was composed of 693 cases (316 women and 377 men) and 698 matched controls (317 women and 381 men) within the Korean Genome and Epidemiology Study. The concentrations of isoflavone biomarkers were measured using HPLC-MS/MS on plasma samples that were collected at baseline. A stratified analysis was undertaken to examine the association between plasma isoflavone concentrations and risk of type 2 diabetes according to sex and equol production. Logistic regression models were used to compute ORs and 95% CIs adjusted for confounders. RESULTS In women, compared with the lowest quartile of plasma concentration of genistein, the highest quartile exhibited a significantly decreased risk of diabetes (OR 0.58, 95% CI 0.35, 0.95). When stratified by equol-producing status in women, the OR for diabetes in the highest vs the lowest quartile of genistein concentration was 0.31 (95% CI 0.16, 0.60) in equol producers, but genistein concentration was not associated with risk of diabetes in equol non-producers (p for interaction = 0.013). In men, isoflavone concentrations were not associated with risk of diabetes, regardless of equol-producing status. CONCLUSIONS/INTERPRETATION High plasma concentrations of genistein were associated with a decreased risk of type 2 diabetes in women. This inverse association was prominent in equol-producing participants. These results suggest a beneficial effect of a high intake of soybean products on risk of type 2 diabetes in women.
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Affiliation(s)
- Kwang-Pil Ko
- Department of Preventive Medicine, Gachon University, Incheon, Korea
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Utian WH, Jones M, Setchell KDR. S-equol: a potential nonhormonal agent for menopause-related symptom relief. J Womens Health (Larchmt) 2015; 24:200-8. [PMID: 25692726 DOI: 10.1089/jwh.2014.5006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Many women suffering from vasomotor symptoms (VMS) are now seeking nonpharmaceutical treatments for symptom relief. Recently, S-equol, an intestinal bacterial metabolite of the soybean isoflavone daidzein has received attention for its ability to alleviate VMS and provide other important health benefits to menopausal women. S-equol is found in very few foods and only in traces. About 50% of Asians and 25% of non-Asians host the intestinal bacteria that convert daidzein into S-equol. Clinical trials that evaluated the efficacy of an S-equol-containing product found that VMS were alleviated but these trials were limited in scope and primarily involved Japanese women for whom hot flashes are a minor complaint. The only trial in the United States evaluating hot flashes found symptoms were significantly reduced by S-equol, but the study lacked a placebo group, although it did include a positive control. The daily dose of S-equol used in most trials was 10 mg, and because the half-life of S-equol is 7-10 hours, to maximize efficacy, it was taken twice daily. Subanalysis of epidemiologic studies suggests that equol producers are more likely to benefit from soyfood consumption than nonproducers with respect to both cardiovascular disease and osteoporosis, although the data are inconsistent. The limited safety data for S-equol do not suggest cause for concern, especially with regard to its effects on breast and endometrial tissue. Further studies are needed before definitive conclusions of its effectiveness for VMS can be made, but the preliminary evidence warrants clinicians discussing the potential of S-equol for the alleviation of VMS with patients.
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Affiliation(s)
- Wulf H Utian
- 1 Scientific Director, Rapid Medical Research , Cleveland, Ohio
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Affiliation(s)
- Shigeto Uchiyama
- Otsuka Pharmaceutical Co., Ltd., Saga Nutraceuticals Research Institute
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10
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Rui X, Xu X, Wu H, Li W, Chen X, Jiang M, Dong M. A survey of equol contents in Chinese stinky tofu with emphasis on the effects of cooking methods. Int J Food Sci Nutr 2014; 65:667-72. [PMID: 24720564 DOI: 10.3109/09637486.2014.908171] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The equol contents of 32 samples of Chinese stinky tofu from different manufacturers in China mainland were determined. The results showed that 15 samples of raw stinky tofu contained substantial amounts of equol (1.16 ± 1.69 mg/100 g, wet basis), in which sample c-4 elicited the highest equol of 6.65 mg/100 g, whereas significantly lower equol contents were found in 17 fried samples (0.15 ± 0.14 mg/100 g, wet basis). A significant strong correlation between equol contents and the amino nitrogen contents (p < 0.01, Pearson correlation coefficient 0.725) was observed which indicated the eqoul content was associated with the fermentation extent. Cooking methods influenced the equol contents. Microwaving and frying tofu rapped with starch paste improved the equol contents, whereas deep frying, stir frying, and stewing had negative effects. The study demonstrated stinky tofu served as a good equol dietary source. Extensive fermentation and delicate cooking approaches were necessary for a high-equol final product.
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Affiliation(s)
- Xin Rui
- Department of Bioengineering, College of Food Science and Technology, Nanjing Agricultural University , Jiangsu Province , P R China
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Ueno T, Abiru Y, Uchiyama S, Ishimi Y. Distribution of 24-h urinary equol excretion as an indicator of the physiological range in healthy Japanese equol excretors. J Funct Foods 2014. [DOI: 10.1016/j.jff.2013.12.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Virk-Baker MK, Barnes S, Krontiras H, Nagy TR. S-(-)equol producing status not associated with breast cancer risk among low isoflavone-consuming US postmenopausal women undergoing a physician-recommended breast biopsy. Nutr Res 2014; 34:116-25. [PMID: 24461312 PMCID: PMC4028846 DOI: 10.1016/j.nutres.2013.12.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 12/09/2013] [Accepted: 12/11/2013] [Indexed: 12/31/2022]
Abstract
Soy foods are the richest sources of isoflavones, mainly daidzein and genistein. Soy isoflavones are structurally similar to the steroid hormone 17β-estradiol and may protect against breast cancer. S-(-)equol, a metabolite of the soy isoflavone daidzein, has a higher bioavailability and greater affinity for estrogen receptor β than daidzein. Approximately one-third of the Western population is able to produce S-(-)equol, and the ability is linked to certain gut microbes. We hypothesized that the prevalence of breast cancer, ductal hyperplasia, and overall breast pathology will be lower among S-(-)equol producing, as compared with nonproducing, postmenopausal women undergoing a breast biopsy. We tested our hypothesis using a cross-sectional study design. Usual diets of the participants were supplemented with 1 soy bar per day for 3 consecutive days. Liquid chromatography-multiple reaction ion monitoring mass spectrometry analysis of urine from 143 subjects revealed 25 (17.5%) as S-(-)equol producers. We found no statistically significant associations between S-(-)equol producing status and overall breast pathology (odds ratio [OR], 0.68; 95% confidence interval [CI], 0.23-1.89), ductal hyperplasia (OR, 0.84; 95% CI, 0.20-3.41), or breast cancer (OR, 0.56; 95% CI, 0.16-1.87). However, the mean dietary isoflavone intake was much lower (0.3 mg/d) than in previous reports. Given that the amount of S-(-)equol produced in the gut depends on the amount of daidzein exposure, the low soy intake coupled with lower prevalence of S-(-)equol producing status in the study population favors toward null associations. Findings from our study could be used for further investigations on S-(-)equol producing status and disease risk.
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Affiliation(s)
- Mandeep K Virk-Baker
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Stephen Barnes
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL, USA; The UAB Comprehensive Cancer Center, Birmingham, AL, USA.
| | - Helen Krontiras
- The UAB Comprehensive Cancer Center, Birmingham, AL, USA; Department of Surgery, Surgical Oncology, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Tim R Nagy
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA; The UAB Comprehensive Cancer Center, Birmingham, AL, USA.
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Tseng M, Byrne C, Kurzer MS, Fang CY. Equol-producing status, isoflavone intake, and breast density in a sample of U.S. Chinese women. Cancer Epidemiol Biomarkers Prev 2013; 22:1975-83. [PMID: 24019393 DOI: 10.1158/1055-9965.epi-13-0593] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Differences in ability to metabolize daidzein to equol might help explain inconsistent findings about isoflavones and breast cancer. We examined equol-producing status in relation to breast density, a marker of breast cancer risk, and evaluated whether an association of isoflavone intake with breast density differs by equol-producing status in a sample of Chinese immigrant women. METHODS Participants were 224 women, ages 36 to 58 years, enrolled in a study on diet and breast density. All women completed dietary recall interviews, underwent a soy challenge to assess equol-producing status, and received a mammogram assessed for breast density using a computer-assisted method. RESULTS In our sample, 30% were classified as equol producers. In adjusted linear regression models, equol producers had significantly lower mean dense tissue area (32.8 vs. 37.7 cm(2), P = 0.03) and lower mean percent breast density (32% vs. 35%, P = 0.03) than nonproducers. Significant inverse associations of isoflavone intake with dense area and percent density were apparent, but only in equol producers (interaction P = 0.05 for both). CONCLUSIONS These results support the possibility that equol-producing status affects breast density and that effects of isoflavones on breast density depend on ability to metabolize daidzein to equol. IMPACT Although these findings warrant confirmation in a larger sample, they offer a possible explanation for the inconsistent findings about soy intake and breast density and possibly breast cancer risk as well. The findings further suggest the importance of identifying factors that influence equol-producing status and exploring appropriate targeting of interventions.
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Affiliation(s)
- Marilyn Tseng
- Authors' Affiliations: Kinesiology Department, California Polytechnic State University, San Luis Obispo, California; Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland; Department of Food Science and Nutrition, University of Minnesota, Saint Paul, Minnesota; and Cancer Prevention & Control Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
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15
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Abstract
OBJECTIVE We evaluated the influence of coffee consumption on diabetes incidence among the Hawaii component of the Multiethnic Cohort (MEC). DESIGN Prospective cohort. SETTING Population-based sample residing in Hawaii. SUBJECTS After exclusions, 75 140 men and women of Caucasian, Japanese American and Native Hawaiian ancestry aged 45-75 years were part of the current analysis. All participants provided information on diet and lifestyle through an FFQ. After 14 years of follow-up 8582 incident diabetes cases were identified using self-reports, medication questionnaires and health plan linkages. Hazard ratios (HR) and 95 % confidence intervals were calculated using Cox regression while adjusting for known covariates. RESULTS The risk for diabetes associated with total coffee consumption differed by sex (P interaction < 0·0001). Women consuming ≥3 cups of any type of coffee daily had a significantly lower risk (HR = 0·66; 95 % CI 0·58, 0·77; P trend < 0·0001) than those reporting <1 cup/d, whereas the relationship in men was borderline (HR = 0·89; 95 % CI 0·80, 0·99; P trend = 0·09). The same difference by sex was seen for regular coffee consumption, with HR of 0·65 (95 % CI 0·54, 0·78; P trend < 0·0001) and 0·86 (95 % CI 0·75, 0·98; P trend = 0·09) in men and women, respectively. No significant association with diabetes was apparent for decaffeinated coffee in women (HR = 0·85; 95 % CI 0·72, 1·01; P trend = 0·73) or men (HR = 1·07; 95 % CI 0·93, 1·23; P trend = 0·71). Despite small differences by ethnicity, the interaction terms between coffee intake and ethnicity were not significant. CONCLUSIONS In this multiethnic population, regular, but not decaffeinated, coffee intake was much more protective against diabetes in women of all ethnic groups than in men.
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Fuhrman BJ, Brinton LA, Pfeiffer RM, Xu X, Veenstra TD, Teter BE, Byrne C, Dallal CM, Barba M, Muti PC, Gierach GL. Estrogen metabolism and mammographic density in postmenopausal women: a cross-sectional study. Cancer Epidemiol Biomarkers Prev 2012; 21:1582-91. [PMID: 22736791 PMCID: PMC3436977 DOI: 10.1158/1055-9965.epi-12-0247] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Prospective studies have consistently found that postmenopausal breast cancer risk increases with circulating estrogens; however, findings from studies of estrogens and mammographic density (MD), an intermediate marker of breast cancer risk, have been inconsistent. We investigated the cross-sectional associations of urinary estrogens, and their 2-, 4-, and 16-hydroxylated metabolites with MD. METHODS Postmenopausal women without breast cancer (n = 194), ages 48 to 82 years, and reporting no current menopausal hormone therapy use were enrolled at a clinic in Western NY in 2005. Urinary estrogens and estrogen metabolites were measured using mass spectrometry. Percent MD and dense area (cm(2)) were measured using computer-assisted analyses of digitized films. Linear regression models were used to estimate associations of log-transformed estrogen measures with MD while adjusting for age, body mass index (BMI), parity, and past hormone therapy use. RESULTS Urinary concentrations of most individual estrogens and metabolites were not associated with MD; however, across the interdecile range of the ratio of parent estrogens (estrone and estradiol) to their metabolites, MD increased by 6.8 percentage points (P = 0.02) and dense area increased by 10.3 cm(2) (P = 0.03). Across the interdecile ranges of the ratios of 2-, 4-, and 16-hydroxylation pathways to the parent estrogens, MD declined by 6.2 (P = 0.03), 6.4 (P = 0.04), and 5.7 (P = 0.05) percentage points, respectively. All associations remained apparent in models without adjustment for BMI. CONCLUSION In this study of postmenopausal women, less extensive hydroxylation of parent estrogens was associated with higher MD. IMPACT Hydroxylation of estrogens may modulate postmenopausal breast cancer risk through a pathway involving MD.
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Affiliation(s)
- Barbara J Fuhrman
- Hormonal and Reproductive Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD 20892, USA.
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Lowry SJ, Sprague BL, Bowles EJA, Hedman CJ, Hemming J, Hampton JM, Burnside ES, Sisney GA, Buist DS, Trentham-Dietz A. Mammographic breast density and serum phytoestrogen levels. Nutr Cancer 2012; 64:783-9. [PMID: 22860715 PMCID: PMC4055295 DOI: 10.1080/01635581.2012.707279] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Some forms of estrogen are associated with breast cancer risk as well as with mammographic density (MD), a strong marker of breast cancer risk. Whether phytoestrogen intake affects breast density, however, remains unclear. We evaluated the association between serum levels of phytoestrogens and MD in postmenopausal women. We enrolled 269 women, ages 55-70 yr, who received a screening mammogram and had no history of postmenopausal hormone use. Subjects completed a survey on diet and factors related to MD and provided a blood sample for analysis of 3 phytoestrogens: genistein, daidzein, and coumestrol. We examined whether mean percent MD was related to serum level of phytoestrogens, adjusting for age and body mass index. Genistein and daidzein levels correlated with self-reported soy consumption. Mean percent MD did not differ across women with different phytoestrogen levels. For example, women with nondetectable genistein levels had mean density of 11.0% [95% confidence intervals (CI) = 9.9-12.4], compared to 10.5% (95% CI = 8.0-13.7) and 11.2% (95% CI = 8.7-14.6) for < and ≥ median detectable levels, respectively. In a population with relatively low soy intake, serum phytoestrogens were not associated with mammographic density. Additional studies are needed to determine effects of higher levels, particularly given patterns of increasing phytoestrogen intake.
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Affiliation(s)
- Sarah J. Lowry
- Group Health Research Institute
- Department of Epidemiology, University of Washington
| | | | | | | | | | | | - Elizabeth S. Burnside
- University of Wisconsin Carbone Cancer Center
- Department of Radiology, University of Wisconsin
| | | | | | - Amy Trentham-Dietz
- University of Wisconsin Carbone Cancer Center
- Department of Population Health Sciences, University of Wisconsin
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Does equol production determine soy endocrine effects? Eur J Nutr 2012; 51:389-98. [PMID: 22366740 DOI: 10.1007/s00394-012-0331-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 02/10/2012] [Indexed: 12/12/2022]
Abstract
Isoflavones, a group of phytoestrogens, are selective oestrogen receptor (ER) modulators. They may positively impact endocrine-related conditions but the current evidence is sparse. Equol, a non-steroidal oestrogen, is produced by the metabolism of the isoflavone daidzein by intestinal bacteria. In Western countries, 30-50% of individuals metabolize daidzein into equol and are known as equol producers. Equol production may be the source of benefit from isoflavones in endocrine disease.
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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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Impact of perinatal exposure to equol enantiomers on reproductive development in rodents. Reprod Toxicol 2011; 32:33-42. [PMID: 21620954 DOI: 10.1016/j.reprotox.2011.05.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 04/15/2011] [Accepted: 05/12/2011] [Indexed: 11/22/2022]
Abstract
There is now considerable interest in the intestinally derived soy isoflavone metabolite, equol, which occurs in the enantiomeric forms, S-(-)equol and R-(+)equol, both differing in biological actions. Little is known about effects of either enantiomer on reproductive development, yet such knowledge is fundamental because of the recent commercialization of S-(-)equol as a dietary supplement. S-(-)equol and R-(+)equol were therefore investigated to determine their effects on reproductive development and fertility in the Sprague-Dawley rat. Neither enantiomer affected fertility, number of litters produced, number of pups per litter, number of male and female pups born, birth weight, anogenital distance, testicular descent or vaginal opening. Histological analysis showed no major abnormalities in ovary, testis, prostate or seminal vesicle tissue with dietary exposure to S-(-)equol or R-(+)equol, but both enantiomers triggered hyperplasia of uterine tissue. With R-(+)equol this stimulatory effect subsided after exposure was discontinued, but the effect of S-(-)equol was prolonged.
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Abstract
The health benefits associated with soya food consumption have been widely studied, with soya isoflavones and soya protein implicated in the protection of CVD, osteoporosis and cancers such as those of the breast and prostate. Equol (7-hydroxy-3-(4'-hydroxyphenyl)-chroman), a metabolite of the soya isoflavone daidzein, is produced via the formation of the intermediate dihydrodaidzein, by human intestinal bacteria, with only approximately 30-40% of the adult population having the ability to perform this transformation following a soya challenge. Inter-individual variation in conversion of daidzein to equol has been attributed, in part, to differences in the diet and in gut microflora composition, although the specific bacteria responsible for the colonic biotransformation of daidzein to equol are yet to be identified. Equol is a unique compound in that it can exert oestrogenic effects, but is also a potent antagonist of dihydrotestosterone in vivo. Furthermore, in vitro studies suggest that equol is more biologically active than its parent compound, daidzein, with a higher affinity for the oestrogen receptor and a more potent antioxidant activity. Although some observational and intervention studies suggest that the ability to produce equol is associated with reduced risk of breast and prostate cancer, CVD, improved bone health and reduced incidence of hot flushes, others have reported null or adverse effects. Studies to date have been limited and well-designed studies that are sufficiently powered to investigate the relationship between equol production and disease risk are warranted before the clinical relevance of the equol phenotype can be fully elucidated.
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Affiliation(s)
- Pamela J Magee
- Northern Ireland Centre for Food and Health, School of Biomedical Sciences, University of Ulster, Coleraine BT52 1SA, UK.
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22
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Abstract
Mechanisms of action of equol described using in vitro studies suggest possible effects of this compound in relation to cancer risk. However, experimental data are lacking with regard to the effects of S-(-)-equol (a gut bacterial product of daidzein), racemic equol, or even daidzein on tumorigenesis in vivo. Rodent studies, using racemic equol or daidzein in equol-producing animals, suggest that equol exposure does not stimulate mammary tumor growth, but there is little evidence that it is protective either. Racemic equol has been shown to inhibit skin carcinogenesis in hairless mice. Epidemiologic studies of associations between urinary or plasma isoflavone concentrations and breast cancer risk in women have reported no association nor increased risk associated with higher equol measures in low-soy-consuming populations but have reported a trend toward decreased cancer risk with increased equol in Asian populations. These population-based differences have been reported for prostate cancer too. Several studies in Asian men report lower equol concentrations or a lower prevalence of equol-producers among men with prostate cancer compared with controls, whereas studies in European populations report no association. Studies using intermediate biomarkers of cancer risk and susceptibility in humans also have examined the effects the equol-producer phenotype in relation to soy intake with varying results. Overall, the role of equol in relation to cancer remains unclear. With the availability of R- and S-equol, animal studies of carcinogenesis and human intervention studies addressing effects of the equol enantiomers on intermediate biomarkers may help to ascertain the role of equol in cancer risk.
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Cho YA, Kim J, Park KS, Lim SY, Shin A, Sung MK, Ro J. Effect of dietary soy intake on breast cancer risk according to menopause and hormone receptor status. Eur J Clin Nutr 2010; 64:924-32. [PMID: 20571498 DOI: 10.1038/ejcn.2010.95] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Although high soy consumption may be associated with lower breast cancer risk in Asian populations, findings from epidemiological studies have been inconsistent. OBJECTIVE We investigated the effects of soy intake on breast cancer risk among Korean women according to their menopausal and hormone receptor status. METHODS We conducted a case-control study with 358 incident breast cancer patients and 360 age-matched controls with no history of malignant neoplasm. Dietary consumption of soy products was examined using a 103-item food frequency questionnaire. RESULTS The estimated mean intakes of total soy and isoflavones from this study population were 76.5 g per day and 15.0 mg per day, respectively. Using a multivariate logistic regression model, we found a significant inverse association between soy intake and breast cancer risk, with a dose-response relationship (odds ratios (OR) (95% confidence interval (CI)) for the highest vs the lowest intake quartile: 0.36 (0.20-0.64)). When the data were stratified by menopausal status, the protective effect was observed only among postmenopausal women (OR (95% CI) for the highest vs the lowest intake quartile: 0.08 (0.03-0.22)). The association between soy and breast cancer risk did not differ according to estrogen receptor (ER)/progesterone receptor (PR) status, but the estimated intake of soy isoflavones showed an inverse association only among postmenopausal women with ER+/PR+ tumors. CONCLUSIONS Our findings suggest that high consumption of soy might be related to lower risk of breast cancer and that the effect of soy intake could vary depending on several factors.
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Affiliation(s)
- Y A Cho
- Cancer Epidemiology Branch, Division of Cancer Epidemiology and Management, Research Institute, National Cancer Center, Gyeonggi-do, South Korea
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Maskarinec G, Verheus M, Tice JA. Epidemiologic studies of isoflavones & mammographic density. Nutrients 2010; 2:35-48. [PMID: 22253990 PMCID: PMC3257610 DOI: 10.3390/nu2010035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Accepted: 01/15/2010] [Indexed: 12/28/2022] Open
Abstract
Isoflavones, phytoestrogens in soy beans with estrogen-like properties, have been examined for their cancer protective effects. Mammographic density is a strong predictor of breast cancer. This review summarizes studies that have examined the association between isoflavones and breast density. Observational investigations in Hawaii and Singapore suggest slightly lower breast density among women of Asian descent with regular soy intake, but two larger studies from Japan and Singapore did not observe a protective effect. The findings from seven randomized trials with primarily Caucasian women indicate that soy or isoflavones do not modify mammographic density. Soy foods and isoflavone supplements within a nutritional range do not appear to modify breast cancer risk as assessed by mammographic density.
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Affiliation(s)
- Gertraud Maskarinec
- Cancer Research Center of Hawaii, 1236 Lauhala Street, Honolulu, HI 96813, USA;
| | - Martijn Verheus
- Cancer Research Center of Hawaii, 1236 Lauhala Street, Honolulu, HI 96813, USA;
| | - Jeffrey A. Tice
- Department of Medicine, University of California, San Francisco, 1701 Divisadero Street, San Francisco, CA 94143, USA;
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Abstract
Gut bacterial modification of soy isoflavones produces metabolites that differ in biological activity from the parent compounds. Hydrolysis of glycosides results in more active compounds. In contrast, further degradation and transformation of aglycones produce more or less active compounds, depending on the substrate metabolized and the product formed. Bacterial metabolism of soy isoflavones varies among individuals. The predominant daidzein metabolites produced by human intestinal bacteria are equol and O-desmethylangolensin. Among humans, 30-50% have the bacteria capable of producing equol and 80-90% harbor O-desmethylangolensin-producing bacteria. Factors that influence the capacity to produce equol and O-desmethylangolensin are not clearly established; however, gut physiology, host genetics, and diet are reported to contribute to interindividual differences in conversion of daidzein to equol. Effects of these phenotypes on human health are poorly characterized. Some studies in high soy-consuming populations reported an inverse association between urinary and serum equol concentrations and breast and prostate cancer risk. Furthermore, several studies of soy supplementation and bone density suggest that soy products may be more effective in maintaining bone density in equol-producing individuals. Factors that contribute to the phenotypes and the relation of these specific phenotypes to human health need to be further elucidated. The extent to which isoflavone metabolism is key to the efficacy of soy foods remains to be established.
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Affiliation(s)
- Johanna W Lampe
- Fred Hutchinson Cancer Research Center and Nutritional Sciences Program, Department of Epidemiology, University of Washington, Seattle, WA, USA.
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Wu AH, Ursin G, Koh WP, Wang R, Yuan JM, Khoo KS, Yu MC. Green tea, soy, and mammographic density in Singapore Chinese women. Cancer Epidemiol Biomarkers Prev 2009; 17:3358-65. [PMID: 19064551 DOI: 10.1158/1055-9965.epi-08-0132] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
There is increasing evidence from observational studies that breast cancer risk is inversely associated with soy and green tea consumption. We investigated the effects of these two dietary agents on mammographic density, a well-established biomarker for breast cancer risk, in a cross-sectional analysis of mammograms and validated food frequency questionnaires from 3,315 Chinese women in Singapore. Percent mammographic density (PMD) was assessed using a reproducible computer-assisted method. We used generalized linear models to estimate PMD by intake of soy, green tea, and black tea while adjusting for potential confounders. Daily green tea drinkers showed statistically significantly lower PMD (19.5%) than non-tea drinkers (21.7%; P = 0.002) after adjusting for relevant covariates. This difference in PMD between daily green tea drinkers and non-tea drinkers remained statistically significant after adjustment for soy (P = 0.002); the effect was more apparent among lower soy consumers (Q1-Q3; 21.9% versus 19.4%; P = 0.002) than in higher (Q4) consumers (20.9% versus 19.5%; P = 0.32). Black tea intake was unrelated to PMD. Only among postmenopausal women who reported very high soy intake (Q4) compared with those with less soy intake was there any association noted between PMD and soy intake (18.9% versus 20.5%; P = 0.035). Following adjustment for green tea intake, the association between soy and PMD was no longer statistically significant (P = 0.52). Our findings suggest that both regular green tea and high soy intake may have beneficial effects on the breast; the effect of green tea on PMD may be stronger than the effect of soy.
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Affiliation(s)
- Anna H Wu
- Department of Preventive Medicine, University of Southern California, 1441 Eastlake Avenue, Los Angeles, CA 90089, USA.
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Estrogenic status modulates the effect of soy on hepatic responses to 7,12-dimethylbenz(a)anthracene (DMBA). Toxicol Appl Pharmacol 2008; 234:89-97. [PMID: 18992763 DOI: 10.1016/j.taap.2008.09.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Revised: 09/29/2008] [Accepted: 09/29/2008] [Indexed: 01/15/2023]
Abstract
We examined the influence of estradiol (E2) status and soy protein isolate (SPI) intake on the hepatic responses altered by 7,12-dimethylbenz(a)anthracene (DMBA, a polycyclic aromatic hydrocarbon [PAH]). Sprague-Dawley rats were ovariectomized (OVX) at PND50 and infused with E2 or vehicle for 14 d and gavaged with 50 mg/kg DMBA or vehicle 24 h before sacrifice at PND64. Rats were fed an AIN-93G diet made with SPI or casein as sole protein source throughout the study. Basal AhR protein levels were reduced (P<0.05) by SPI feeding irrespective of the E2 status. However, DMBA increased (P<0.05) AhR-induced CYP1A1 gene expression in OVX, SPI-fed rats, but reduced (P<0.05) CYP1A1 in OVX+E2, SPI-fed rats. Chromatin-immunoprecipitation demonstrated lower (P<0.05) DMBA-mediated recruitment of estrogen receptor alpha to the CYP1A1 promoter by SPI feeding in the presence of E2, suggesting an estrogen-like action of SPI on DMBA-mediated signaling in the absence of E2. Further, microarray analysis (Rat 230-2.0 Affymetrix-GeneChip) revealed 231 genes common to SPI+DMBA and SPI+E2+DMBA (normalized to E2) treatments. AhR-activated genes (CYP1A1, CYP1A2, and NQO1) were down-regulated by SPI+E2+DMBA compared to SPI+DMBA. Unique interactions among SPI, DMBA and E2 altered the expression profile of 316 genes, not observed by either treatment alone. Our data suggest that although E2 status does not effect soy-mediated AhR degradation, it modulates the effects of soy on many genes, including CYP1A1.
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Daidzein-metabolizing phenotypes in relation to mammographic breast density among premenopausal women in the United States. Breast Cancer Res Treat 2008; 116:587-94. [PMID: 18821061 DOI: 10.1007/s10549-008-0199-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Accepted: 09/15/2008] [Indexed: 10/21/2022]
Abstract
BACKGROUND Mammographic breast density is an established marker of breast cancer risk, and is hormonally sensitive. Studies suggest that production of the daidzein metabolites equol and O-Desmethylangolensin (ODMA) may be associated with hormones and hormonally mediated factors, but few studies have assessed relationships between the capacity to produce these metabolites and breast density. OBJECTIVE To evaluate the relationship between equol- and ODMA-producer phenotypes and breast density in premenopausal women in the United States. DESIGN Two hundred and three women attended a clinic visit and 200 provided a urine sample following a 3 day soy challenge. Samples were analyzed for isoflavones by GC-MS to determine daidzein-metabolizing phenotypes. Percent density on recent (<14 month prior to their clinic visit) mammograms was assessed by one reader using a computer-assisted method. Multiple regression analysis was used to assess relationships between the production of equol and ODMA and breast density. Results 55(27.5%) and 182(91%) women were classed as equol- and ODMA-producers (>87.5 ng/ml urine), respectively. In unadjusted and adjusted analyses, there were no differences in breast density between producers and non-producers of either equol or ODMA (P > 0.05). CONCLUSION In this population of low-soy consuming premenopausal women, there were no associations between daidzein-metabolizing phenotypes and breast density, suggesting that these phenotypes per se do not influence premenopausal breast density.
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