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Messina MJ, Messina V, Nagata C. Perspective: Observational Studies Involving Low-Soy Intake Populations Have Limited Ability for Providing Insight into the Health Effects of Soybean Isoflavones. Adv Nutr 2024; 15:100210. [PMID: 38484974 PMCID: PMC10992291 DOI: 10.1016/j.advnut.2024.100210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 02/28/2024] [Accepted: 03/11/2024] [Indexed: 04/01/2024] Open
Abstract
Isoflavones are naturally occurring plant compounds found in uniquely high amounts in soybeans and foods made from this legume. These soybean constituents have been proposed to exert several health benefits and as such they have been the subject of an enormous amount of research. This research includes randomized controlled trials (RCTs) and epidemiologic investigations. Although statistically significant associations between isoflavone intake and a wide range of health outcomes have been identified in cohorts involving low-isoflavone intake populations, we suggest that these associations are unlikely to have a causal basis because exposure is too low for isoflavones to exert physiologic effects. In cohorts involving predominantly non-Asian, non-vegetarian populations, the highest isoflavone intake category is typically ≤3 mg/d, an amount of isoflavones provided by ∼30 mL (2 tablespoons) of soymilk made from whole soybeans. In comparison, mean isoflavone intake in the upper intake categories in observational studies involving high-isoflavone intake populations is typically ≥50 mg/d. In RCTs, intervention doses of isoflavones typically range between 40 and 100 mg/d. Health professionals advising patients and clients about soy food and isoflavone intake need to be aware of the limitations of epidemiologic research involving low-isoflavone intake populations. Intake recommendations are best based on the results of RCTs using clinically relevant doses of isoflavones and epidemiologic studies involving populations for whom soy foods are a habitual part of the diet.
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Affiliation(s)
- Mark J Messina
- Soy Nutrition Institute Global, Jefferson City, MO, United States.
| | | | - Chisato Nagata
- Department of Epidemiology and Preventive Medicine, Gifu University Graduate School of Medicine, Gifu, Japan
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Messina M, Duncan A, Messina V, Lynch H, Kiel J, Erdman JW. The health effects of soy: A reference guide for health professionals. Front Nutr 2022; 9:970364. [PMID: 36034914 PMCID: PMC9410752 DOI: 10.3389/fnut.2022.970364] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 07/25/2022] [Indexed: 11/22/2022] Open
Abstract
Soy is a hotly debated and widely discussed topic in the field of nutrition. However, health practitioners may be ill-equipped to counsel clients and patients about the use of soyfoods because of the enormous, and often contradictory, amount of research that has been published over the past 30 years. As interest in plant-based diets increases, there will be increased pressure for practitioners to gain a working knowledge of this area. The purpose of this review is to provide concise literature summaries (400-500 words) along with a short perspective on the current state of knowledge of a wide range of topics related to soy, from the cholesterol-lowering effects of soy protein to the impact of isoflavones on breast cancer risk. In addition to the literature summaries, general background information on soyfoods, soy protein, and isoflavones is provided. This analysis can serve as a tool for health professionals to be used when discussing soyfoods with their clients and patients.
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Affiliation(s)
- Mark Messina
- Soy Nutrition Institute Global, Washington, DC, United States
| | - Alison Duncan
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | | | - Heidi Lynch
- Kinesiology Department, Point Loma Nazarene University, San Diego, CA, United States
| | - Jessica Kiel
- Scientific and Clinical Affairs, Medifast Inc., Baltimore, MD, United States
| | - John W. Erdman
- Division of Nutritional Sciences and Beckman Institute, Department of Food Science and Human Nutrition, University of Illinois at Urbana/Champaign, Urbana, IL, United States
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Bosland MC, Enk E, Schmoll J, Schlicht MJ, Randolph C, Deaton RJ, Xie H, Zeleniuch-Jacquotte A, Kato I. Soy protein supplementation in men following radical prostatectomy: a 2-year randomized, placebo-controlled clinical trial. Am J Clin Nutr 2021; 113:821-831. [PMID: 33564828 PMCID: PMC8024002 DOI: 10.1093/ajcn/nqaa390] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 11/23/2020] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Many studies have addressed effects of dietary supplementation with soy protein, but most have been inconsistent and few have been long-term studies in men. OBJECTIVES This study was a secondary analysis of body weight, blood pressure, thyroid hormones, iron status, and clinical chemistry in a 2-y trial of soy protein supplementation in middle-aged to older men. METHODS Data were analyzed as secondary outcomes of a randomized controlled trial of dietary supplementation with 20 g/d soy protein isolate, providing 41 mg/d total isoflavones and 23 mg/d genistein, in 44- to 75-y-old men who were at risk of cancer recurrence following prostatectomy randomized to soy (n = 50) or a casein-based placebo (n = 43). Weight, blood pressure, and blood samples were collected at baseline, every 2 mo in year 1, and every 3 mo in year 2. RESULTS Compared with casein, soy supplementation did not affect body weight, blood pressure, serum total cholesterol, calcium, phosphorus, and thyroid hormones. Serum ferritin concentrations doubled over 2 y in both groups (117-129%), whereas hemoglobin and hematocrit increased slightly. In an exploratory subgroup analysis of soy group data, weight increased in subjects producing equol but not in nonproducers. Blood pressure was reduced in nonequol producers but not in producers. Other endpoints were not affected by equol production status. CONCLUSIONS Soy protein supplementation for 2 y compared with a casein-based placebo did not affect body weight, blood pressure, serum total cholesterol, iron status parameters, calcium, phosphorus, and thyroid hormones. Exploratory analysis suggests that equol production status of subjects on soy may modify effects of soy on body weight and possibly blood pressure. This trial was registered at clinicaltrials.gov as NCT00765479.
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Affiliation(s)
| | - Erika Enk
- Department of Pathology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Joanne Schmoll
- Department of Environmental Medicine, New York University School of Medicine, New York, NY, USA
| | - Michael J Schlicht
- Department of Pathology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Carla Randolph
- Department of Environmental Medicine, New York University School of Medicine, New York, NY, USA
| | - Ryan J Deaton
- Department of Pathology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Hui Xie
- Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, Chicago, IL, USA
| | | | - Ikuko Kato
- Department of Environmental Medicine, New York University School of Medicine, New York, NY, USA,Departments of Oncology and Pathology, Wayne State University, Detroit, MI, USA
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Soltani S, Boozari M, Cicero AFG, Jamialahmadi T, Sahebkar A. Effects of phytochemicals on macrophage cholesterol efflux capacity: Impact on atherosclerosis. Phytother Res 2021; 35:2854-2878. [PMID: 33464676 DOI: 10.1002/ptr.6991] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 10/19/2020] [Accepted: 12/11/2020] [Indexed: 12/24/2022]
Abstract
High-density lipoprotein cholesterol (HDL) is the major promoter of reverse cholesterol transport and efflux of excess cellular cholesterol. The functions of HDL, such as cholesterol efflux, are associated with cardiovascular disease rather than HDL levels. We have reviewed the evidence base on the major classes of phytochemicals, including polyphenols, alkaloids, carotenoids, phytosterols, and fatty acids, and their effects on macrophage cholesterol efflux and its major pathways. Phytochemicals show the potential to improve the efficiency of each of these pathways. The findings are mainly in preclinical studies, and more clinical research is warranted in this area to develop novel clinical applications.
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Affiliation(s)
- Saba Soltani
- Department of Pharmacognosy, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Motahareh Boozari
- Department of Pharmacognosy, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Arrigo F G Cicero
- Hypertension and Cardiovascular Risk Factors Research Center, Medical and Surgical Sciences Department, University of Bologna, Bologna, Italy
| | - Tannaz Jamialahmadi
- Department of Food Science and Technology, Quchan Branch, Islamic Azad University, Quchan, Iran.,Department of Nutrition, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran.,Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,Halal Research Center of IRI, FDA, Tehran, Iran.,Polish Mother's Memorial Hospital Research Institute (PMMHRI), Lodz, Poland
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Otun J, Sahebkar A, Östlundh L, Atkin SL, Sathyapalan T. Systematic Review and Meta-analysis on the Effect of Soy on Thyroid Function. Sci Rep 2019; 9:3964. [PMID: 30850697 PMCID: PMC6408586 DOI: 10.1038/s41598-019-40647-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 02/20/2019] [Indexed: 12/16/2022] Open
Abstract
Soy foods have had an important dietary role in Asian countries for centuries, and in recent years they have become increasingly popular in Western countries as a result of their suggested health benefits. Nevertheless, there are some concerns that soy can have a negative effect on thyroid function and can alter the levels of thyroid hormones. The aim of this systematic review was to investigate the link between soy or soy product consumption and thyroid function via the measurement of thyroid hormone levels. A systematic review and meta-analysis was undertaken on all randomised controlled trials of studies including soy as an intervention and where free triiodothyronine (fT3), free thyroxine (fT4) and thyroid stimulating hormone (TSH) was measured. The search included PubMed, MEDLINE, EMBASE, Cochrane and sources for the grey literature. Quantitative data synthesis was performed using a random-effects model, with standardized mean difference (SMD) and 95% confidence interval as summary statistics. A total of 18 articles were suitable for review. The meta-analysis showed no significant changes in fT3 (WMD: 0.027 pmol/L, 95% CI: -0.052, 0.107, p = 0.499; I2: 55.58%), fT4 (WMD: -0.003 pmol/L, 95% CI: -0.018, 0.011, p = 0.656; I2: 87.58%) while an elevation in TSH levels was observed (WMD: 0.248 mIU/L, 95% CI: 0.001, 0.494, p = 0.049; I2: 80.31%) levels with soy supplementation. There was no evidence of publication bias. Soy supplementation has no effect on the thyroid hormones and only very modestly raises TSH levels, the clinical significance, if any, of the rise in TSH is unclear.
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Affiliation(s)
- Jemiliat Otun
- Academic Diabetes, Endocrinology and Metabolism, Hull York Medical School, University of Hull, Hull, UK.
| | - Amirhossein Sahebkar
- Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
- School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Linda Östlundh
- National Medical Library, College of Medicine and Health Sciences, UAE University, Al Ain, UAE
| | | | - Thozhukat Sathyapalan
- Academic Diabetes, Endocrinology and Metabolism, Hull York Medical School, University of Hull, Hull, UK
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Konya J, Sathyapalan T, Kilpatrick ES, Atkin SL. The Effects of Soy Protein and Cocoa With or Without Isoflavones on Glycemic Control in Type 2 Diabetes. A Double-Blind, Randomized, Placebo-Controlled Study. Front Endocrinol (Lausanne) 2019; 10:296. [PMID: 31143160 PMCID: PMC6521701 DOI: 10.3389/fendo.2019.00296] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 04/25/2019] [Indexed: 12/21/2022] Open
Abstract
Objective: Soy and cocoa have been suggested to be beneficial for diabetes. The aim of this study was to identify the effects of soy protein, isoflavones, and cocoa on glycemic control parameters. Research design and methods: The study was a parallel, double-blind, placebo-controlled study where patients with diet or metformin controlled type 2 diabetes were randomized to, casein soy protein with or without isoflavones (SPI, SP), and with or without cocoa (SPIC, SPC) arms for an 8 week period. Glycemic control and cardiovascular risk factors were assessed prior to and after the completion of the dietary intervention. Sixty participants completed the study. Results: Soy protein improved HbA1c compared to casein (p < 0.05). The addition of isoflavones improved indices of insulin resistance and LDL [delta QUICKIE (SPI: -0.12 ± 0.04 vs. SP: 0.03 ± 0.06, p = 0.03); delta LDL (-0.27 ± 0.41 vs. 0.22 ± 0.43, p = 0.02); percentage change in HOMA (31.02 ± 54.75 vs. -14.42 ± 27.07, p = 0.02); percentage change in QUICKIE (-3.89 ± 7.07 vs. 6.11 ± 10.54, p = 0.01)]. However, the addition of cocoa provided no benefit with or without isoflavones. Summary: Soy protein had intrinsic activity on glycemic control compared to casein. Isoflavones improved both insulin resistance and LDL, but cocoa did not have added benefit on these indices. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT01754662.
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Affiliation(s)
- Judit Konya
- Diabetes Research Centre, University of Hull, Kingston upon Hull, United Kingdom
| | | | | | - Stephen L. Atkin
- Weill Cornell Medicine, Doha, Qatar
- *Correspondence: Stephen L. Atkin
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Pistollato F, Masias M, Agudo P, Giampieri F, Battino M. Effects of phytochemicals on thyroid function and their possible role in thyroid disease. Ann N Y Acad Sci 2018; 1443:3-19. [DOI: 10.1111/nyas.13980] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 09/10/2018] [Accepted: 09/18/2018] [Indexed: 12/20/2022]
Affiliation(s)
- Francesca Pistollato
- Center for Nutrition & Health, CITICANUniversidad Europea del Atlántico, Parque Científico y Tecnológico de Cantabria Santander Spain
| | - Manuel Masias
- Center for Nutrition & Health, CITICANUniversidad Europea del Atlántico, Parque Científico y Tecnológico de Cantabria Santander Spain
- Área de Nutrición y SaludUniversidad Internacional Iberoamericana (UNINI) Campeche Mexico
| | - Pablo Agudo
- Center for Nutrition & Health, CITICANUniversidad Europea del Atlántico, Parque Científico y Tecnológico de Cantabria Santander Spain
| | - Francesca Giampieri
- Dipartimento di Scienze Cliniche Specialistiche ed Odontostomatologiche, Sez, BiochimicaUniversità Politecnica delle Marche Ancona Italy
| | - Maurizio Battino
- Dipartimento di Scienze Cliniche Specialistiche ed Odontostomatologiche, Sez, BiochimicaUniversità Politecnica delle Marche Ancona Italy
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