Gaining Insight into the Health Effects of Soy but a Long Way Still to Go: Commentary on the Fourth International Symposium on the Role of Soy in Preventing and Treating Chronic Disease

Department of Medicine, Stanford University, Stanford, California, United States
Journal of Nutrition (Impact Factor: 3.88). 04/2002; 132(3):547S-551S.
Source: PubMed


Research into the health effects of soyfoods and soybean constituents has increased at a phenomenal pace over the past decade. This research includes a wide range of areas, such as cancer, coronary heart disease, osteoporosis, cognitive function, menopausal symptoms and renal function. Importantly, there are an increasing number of clinical studies being conducted in this field, which was quite evident from the findings presented at the Fourth International Symposium on the Role of Soy in Preventing and Treating Chronic Disease, November 4-7, 2001, in San Diego, California. There is no doubt that progress in understanding the health effects of soy is being made, but much of the data are frustratingly inconsistent. For example, there were conflicting results presented at the symposium on the role of isoflavones in bone health. Similarly, presentations painted an unclear picture of the role of isoflavones in cholesterol reduction. The relatively short duration and small sample size of many of the human studies in this field likely contribute to the inconsistent results. Although there are some controversies regarding the safety of soy for certain subsets of the population, special sessions at the symposium on breast cancer and cognitive function did much to alleviate concerns that soy could have detrimental effects in these areas. Furthermore, published data and new research presented at this meeting suggest that the consumption of even 10 g (typical of Asian intake) of isoflavone-rich soy protein per day may be associated with health benefits. If this modest amount of soy protein were to be incorporated in the American diet, it would represent only approximately 15% of total U. S. protein intake.

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    • "The relationship between equol production and blood pressure was reported by Tormala et al. (2007), who examined blood pressure in tibolone-treated postmenopausal women and concluded that equol producers had lower blood pressure compared with nonproducers. Additional reports have suggested that soy products reduce the risk of coronary artery disease (Clarkson 2002; Messina et al. 2002). Our GWAS identified a candidate gene as a host genetic factor, HACE1, which encodes C-terminal homologous to E6-associating protein carboxyl terminus (HECTc) ubiquitin-protein ligase domain and ankyrin repeat-containing E3 ubiquitin-protein ligase 1. HACE1 lies on chromosome 6q21, and translocations in this region have been reported in Wilms' tumor (Bruce et al. 2003). "
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    ABSTRACT: Equol is a daidzein (a phytoestrogen isoflavone) metabolite of gut bacteria, and the ability to produce equol varies between individuals and reduces the risks of several diseases. We tested the effects of equol production on health in Koreans and identified the genetic factors that determine the equol-producing phenotype. In 1391 subjects, the equol-producing phenotype was determined, based on measurements of serum equol concentrations. The anthropometric and blood biochemical measurements between equol producers and nonproducers were analyzed by LC-MS/MS. Genetic factors were identified in a genomewide association study (GWAS), and the interaction between genetic factors and the equol-producing phenotype was examined. We observed that 70.1 % of the study population produced equol. Blood pressure was significantly lower in equol producers (beta ± SE = -1.35 ± 0.67, p = 0.045). In our genomewide association study, we identified 5 single-nucleotide polymorphisms (p < 1 × 10(-5)) in HACE1. The most significant SNP was rs6927608, and individuals with a minor allele of rs6927608 did not produce equol (odds ratio = 0.57 (95 % CI 0.45-0.72), p value = 2.5 × 10(-6)). Notably, the interaction between equol production and the rs6927608 HACE1 SNP was significantly associated with systolic blood pressure (p value = 1.3 × 10(4)). Equol production is linked to blood pressure, and HACE1, identified in our (GWAS), might be a determinant of the equol-producing phenotype.
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    • "Indeed a number of beneficial effects were reported. Despite the large number of studies that have been performed, many conflicting data have been found, especially in relation to the prevention of chronic diseases (Balk et al., 2005; Messina et al., 2002). Soya is associated with beneficial health effects on cardiovascular diseases, menopausal symptoms, endocrine function, cancer, bone health, reproductive health, kidney diseases, cognitive function and glucose metabolism. "

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    • "Data obtained from clinical, epidemiological and nutritional studies in animals and humans show that the improved metabolic consequences associated with ingestion of soy products include better glucose control, less insulin resistance and improved plasma lipid profile (reducing serum total cholesterol, low-density lipoprotein (LDL)-cholesterol and triglycerides) (Zhuo et al., 2004; Zhan and Ho, 2005; Taku et al., 2007), as well as reduction of weight gain in rats (Davis et al., 2007). Such changes are protective in disorders like hyperlipidaemia, cardiovascular disease, menopausal symptoms, atherosclerosis, osteoporosis, cancer and various forms of chronic renal disease (Kopelman, 2000; Clarkson, 2002; Messina et al., 2002; Clair and Anthony, 2005; Cassidy and Hooper, 2006; Zhang et al., 2010), all of which are associated with obesity and diabetes. "
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