Intake Of Soy Products Research Articles

Nutritional Epidemiology of Type 2 Diabetes and Depressive Symptoms

In Japan, the prevalences of type 2 diabetes and depression are increasing, but evidence linking these diseases to diet is limited. The present study reviewed the association of type 2 diabetes with intakes of rice, fish/seafood, and soy product and isoflavone, and the association of depressive symptoms with folate, vitamin D, and dietary pattern, in the Japanese population. The analysis of type 2 diabetes comprised around 55 000 men and women aged 45 to 75 years who completed a questionnaire for the Japan Public Health Center-based Prospective Study and were free of type 2 diabetes at baseline. The odds ratio of self-reported physician-diagnosed type 2 diabetes during the subsequent 5 years increased with rice intake among women and among physically inactive men but decreased with total fish/seafood intake among men. In addition, risk tended to decrease with soy product and isoflavone intake among overweight and postmenopausal women. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale. The participants were approximately 530 workers aged 21 to 67 years who participated in a health survey at the time of a periodic health check. A cross-sectional and prospective inverse association between serum folate and depressive symptoms was observed. Serum 25-hydroxyvitamin D level was suggestively associated with decreased prevalence of depressive symptoms in late autumn. In addition, a healthy Japanese pattern—characterized by high intakes of vegetables, fruit, mushrooms, and soy products—was inversely associated with depressive symptoms. The findings suggest that diet has a role in the development of type 2 diabetes and depression in Japanese.

Systematic review and meta-analysis of soy products consumption in patients with type 2 diabetes mellitus.

Clinical trials have reported the lipid-lowering effect of consuming soy products, and epidemiological studies have shown that soy intake is associated with decreased risk of type 2 diabetes mellitus (T2DM). The aim of this meta-analysis was to systematically review the effects of soy products consumption on serum lipid profiles and glycaemic control in T2DM patients. Potential papers were initially searched from PubMed (1966 to 2010) and Cochrane Library (1984 to 2010) without language limitations. All randomized controlled trials were included in which soy products supplementation was the only intervention in subjects with type 2 diabetes. Weighted mean effect size was calculated for net changes in serum lipids and fasting glucose concentrations using fixed-effect or random-effect models. Previously defined subgroup analyses were performed to identify the source of heterogeneity. Eight studies were included according to the criteria. The intake of soy products was associated with a significant reduction in serum total cholesterol (by 0.42 mmol/L; 95% confidence interval (CI): -0.70, -0.14; p<0.001), triacylglycerol (by 0.22 mmol/L; 95% CI: -0.38, -0.07; p<0.001) and low-density lipoprotein-cholesterol (by 0.30 mmol/L; 95% CI: -0.60, -0.00; p<0.001), and a significant increase in high-density lipoprotein-cholesterol (0.05 mmol/L; 95% CI: 0.04, 0.06; p=0.89). There were no significant effects on fasting glucose, insulin and glycated hemoglobin. It can be concluded that intake of soy and soy products has beneficial effects in T2DM patients in relation to serum lipids.

Nutrition in bone growth and development

The greatest increase in bone density was observed around ages 10-14 years in girls and thereafter peak bone mass was attained. Maximizing peak bone mass during adolescence is one of the most important strategies to decrease osteoporotic fractures later in life. Initial bone mass adjusted by height and weight in 10-year-old girl was associated positively with intakes of dairy products and small fish. Annual increase in bone mass from age 10 years to 11 years was associated positively with increased intake of fish, fruit, vegetables, and soybeans. Thus, not only calcium but also adequate dietary patterns such as increased intake of fish, fruit, vegetables, and soy products lead to higher peak bone mass in adolescent and will decrease the risk of bone fracture in postmenopausal age.

Legumes and soy products consumption and functional disability in older women

Objectives This study was to examine the association between frequency of legumes and soy products consumption and functional disability in older Korean women. Study design Cross-sectional study. Data came from the 2005 Korea National Health and Nutrition Examination Survey (KNHANES). Subjects were 562 women aged 65 years and older living in the community. Main outcome measures Frequency of legume consumption was obtained by using food frequency questionnaire and functional disability was assessed using the instrumental activities of daily living (IADL) and ADL scales. Poisson regression analyses were conducted to examine the association of frequency of legume and soy consumption with functional disability, controlling for covariates. Results Dietary intake of legumes and soy products was associated with a significantly reduced risk of IADL disability after controlling for potential risk factors ( p = 0.002 for trend). Compared with women who consumed legumes and soy products <1 time per week, those who consumed ≥3 times per day had a reduced risk of IADL disability (prevalence ratio = 0.70; 95% confidence interval: 0.51–0.96). In contrast, legumes and soy products consumption was not significantly associated with ADL disability. Conclusions Frequent legumes and soy products consumption was inversely associated with IADL disability in older women. Further studies are needed to clarify the protective effect of legume consumption on functional disability in older people.

Soy Product and Isoflavone Intakes Are Associated with a Lower Risk of Type 2 Diabetes in Overweight Japanese Women

Isoflavones have been shown to improve glucose metabolism, but epidemiologic data are limited. We prospectively investigated the relationship between soy product and isoflavone intake and the risk of developing type 2 diabetes among Japanese adults. Participants were 25,872 men and 33,919 women aged 45–75 y, who participated in the second survey of the Japan Public Health Center-Based Prospective Study and had no history of diabetes. Soy product and isoflavone intakes were ascertained using a 147-item FFQ. Odds ratios of self-reported, physician-diagnosed type 2 diabetes over 5 y were estimated using logistic regression analysis. A total of 1114 new cases of type 2 diabetes were self-reported. Intakes of soy products and isoflavones were not significantly associated with type 2 diabetes in either men or all women. However, among overweight women (BMI ≥25 kg/m2), a higher intake of soy products was associated with a lower risk of type 2 diabetes; multivariable-adjusted odds ratios (95% CI) for the lowest through highest quintiles of soy product intake were 1.00 (reference), 0.78 (0.52–1.18), 0.79 (0.52–1.20), 0.62 (0.39–0.99), and 0.89 (0.55–1.44), respectively, and we found a similar risk pattern for daidzein and genistein intakes. Overall, our results suggest that there are no benefits of soy product or isoflavone intake with respect to risk of type 2 diabetes in either men or women. The possible protective associations of soy and isoflavone intakes among overweight women deserves further investigation.

Soy product and isoflavone intake and breast cancer risk defined by hormone receptor status

The association between soy food consumption and breast cancer risk has been inconsistent. A hospital-based case-control study was conducted to assess the relationship between soy food intake and breast cancer risk according to the estrogen receptor (ER) and/or progesterone receptor (PR) status of breast cancer in Chinese women residing in Guangdong province from June 2007 to August 2008. A total of 438 consecutively recruited cases with primary breast cancer were frequency matched to 438 controls by age (5-year interval) and residence (rural/urban). Dietary intake was assessed by face-to-face interviews using a validated food frequency questionnaire. Odds ratios (OR) and 95% confidence intervals (CI) were obtained by using multiple unconditional logistic regression adjusted for the potential confounders. We observed a statistically significant inverse association between soy isoflavone and soy protein intake with breast cancer risk. The multivariate ORs (95% CIs) of breast cancer risk for the highest quartile compared with the lowest quartile were 0.54 (0.34-0.84) for soy isoflavone and 0.62 (0.40-0.96) for soy protein, respectively. A preventive effect of soy food was found for all subtypes of ER and/or PR status of breast cancer. The inverse association was more evident among premenopausal women. This study suggests that consumption of soy food, soy isoflavone, is inversely associated with the risk of breast cancer. The protective effects of soy did not seem to differ by ER and PR breast cancer status.

Effect of genistein therapy on plasma levels of asymmetric dimethylarginine in healthy postmenopausal women: a randomized, placebo-controlled study

The aim of this study was to investigate the effects of pure genistein therapy on asymmetric dimethylarginine in healthy postmenopausal women. Healthy postmenopausal women received pure genistein (n=21) or placebo (n=17) for 6 months, and no statistically significant effects on plasma asymmetric dimethylarginine levels were found with pure genistein treatment.

Soy intake and risk of endocrine‐related gynaecological cancer: a meta‐analysis

Epidemiology studies have reported associations between soy intake and the risk of endocrine-related gynaecological cancers. However, to date there have been no quantitative meta-analyses reported regarding this topic. We investigated the quantitative associations between soy food intake and the risk of endometrial cancer and ovarian cancer by a meta-analysis of case-control studies and cohort studies. We searched MEDLINE (PubMed), EMBASE and the Cochrane Library during October 2008 using common keywords related to soy intake and endometrial or ovarian cancer. Two evaluators independently reviewed and selected articles, based on predetermined selection criteria. Included studies met all of the following criteria: (1) a case-control study or cohort study (to date, no randomized controlled trials have been reported); (2) investigated the associations between 'soy or soy product intake' and 'endometrial cancer' or 'ovarian cancer'; (3) reported outcome measures with adjusted odds ratios (OR) or relative risks (RR) and 95% confidence intervals (CI). We investigated the associations between the overall soy intake (highest versus lowest intake) and the risk of endocrine-related gynaecological cancers (endometrial or ovarian cancer) as the main analysis. We also performed subgroup analyses by type of cancer (endometrial or ovarian), type of study design (case-control or cohort) and type of soy intake (soy foods or soy constituents). Out of 477 articles that met our initial criteria, a total of seven epidemiology studies consisting of five case-control studies and two cohort studies were included in the final analyses. Compared with the lowest soy intake, the OR for the highest soy intake was 0.61 (95% CI, 0.53-0.72) of all endocrine-related cancers among seven studies; 0.70 for endometrial cancer (95% CI, 0.57-0.86) and 0.52 for ovarian cancer (95% CI, 0.42-0.66) in the fixed-effects meta-analyses. The subgroup analyses by study design showed similar findings among the case-control studies (OR, 0.62; 95% CI, 0.53-0.73) and the cohort studies (OR, 0.57; 95% CI, 0.36-0.90). The results of the current study showed protective effects of soy intake on the risk for endocrine-related gynaecological cancers. Additional larger prospective studies are now needed.

An investigation of the association between diet and occurrence of acne: a rational approach from a traditional Chinese medicine perspective

The association between diet and acne vulgaris has long been suggested but remains unproven in western medicine. In contrast, the diet-acne relationship is considered important in traditional Chinese medicine (TCM). Aim. To investigate the association between diet and acne, using a TCM approach. Using a cross-sectional study of 322 entrants to a university in Hong Kong, China, we examined the participants' clinical severity of acne using the Global Acne Grading System and the participants' yin and yang scores using a quantitative method. We then divided them into two groups, a yin-predominant group (yin-PG) and a yang-predominant group (yang-PG) before the diet-acne relationship was investigated. In total, 82 (25.2%) participants were in the clinical acne group and 240 (74.5%) were in the reference group. There were 155 (48.1%) participants in the yin-PG and 167 (51.9%) in the yang-PG group. No association of diet and acne was found when the participants were considered as a homogenous group. In yin-PG, intake of foods from street stalls (P = 0.04) was significantly associated with a lower incidence of acne. In yang-PG, the intake of desserts (P = 0.04) and fresh fruit juices (P = 0.02) was significantly associated with a higher incidence of acne, whereas the intake of dairy and soy products (P = 0.04) was significantly associated with a lower incidence of acne. The application of a TCM approach led to the detection of significant associations between diet and the incidence of acne.

Antimitotic peptide characterized from soybean: role in protection from cancer?

Cell proliferation, or mitosis, is believed to play a central role in the multistep process of carcinogenesis. The recent identification, cloning, and characterization of a potent antimitotic peptide from soybeans is, therefore, of interest in view of epidemiologic associations between intake of soy products and reduced cancer risk. Several questions must be resolved, however, before the biochemistry and epidemiology can be linked.

Tumor suppressor PTEN signaling is up-regulated in mammary epithelial cells by soy isoflavone genistein: implications for breast cancer protection.

Abstract Abstract #4069 Breast cancer is the second leading cause of death in the Western hemisphere affecting one of eight women in their lifetime. In addition to chromosomal and genetic alterations, nutrition is considered a risk determinant for breast cancer. Prevailing evidence suggests a negative correlation between intake of soy-rich foods and breast cancer incidence. Epidemiological and case control studies have shown a two-to eight fold lower occurrence of the disease in Asian women whose early intake of soy products is 20-25 times higher than their American counterparts. Previous work from our group has shown diet-induced protection against DMBA- and NMU-induced mammary tumors in vivo, with decreased tumor incidence and increased tumor latency in rats exposed to dietary soy protein isolate (SPI) or casein (CAS) supplemented with the major soy isoflavone genistein (GEN) when compared to those fed the control casein (CAS) diet. We also have shown that GEN enhanced apoptosis in mammary epithelial cells in vivo and in vitro (MCF-7 cells), attendant with increased expression of the tumor suppressor PTEN and several pro-apoptotic genes Bax, Bok, and p21. Here, we test the hypothesis that GEN induction of PTEN expression and nuclear localization in mammary epithelial cells result in decreased cellular proliferation and enhanced cellular differentiation, to confer protection from mammary tumorigenesis. Using the non-tumor human mammary epithelial cell line MCF-10A, we show that GEN at physiologically relevant concentrations (40 nM, 2 µM) increased PTEN mRNA and protein levels and enhanced nuclear accumulation of active (non-phosphorylated) PTEN. GEN induction of PTEN transcript levels was lost with the inclusion of the transcription inhibitor actinomycin D, suggesting PTEN is a direct GEN target. Further, cells treated with GEN for 6 days had lower cell viability when compared to control cells, concomitant with decreased expression of cyclin D1 and of the PTEN regulated gene pleiotrophin. Interestingly, GEN up-regulation of PTEN expression was accompanied by similar effects on another tumor suppressor p53, which co-localized with PTEN in the nuclei of GEN-treated cells. PTEN siRNA targeting, which decreased basal PTEN expression by 60%, significantly increased cyclin D1 but not p53 expression. Our findings provide support to the hypothesis that the protective effects of GEN in the mammary epithelium may be mediated by PTEN to enhance differentiation and inhibit cellular proliferation, and suggest the participation of another key tumor suppressor p53. Funding by USDA-CRIS 6251-5100002-06S. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4069.

Repressive effect of the phytoestrogen genistein on estradiol-induced uterine leiomyoma cell proliferation

Objective. Uterine leiomyomas are the most common gynecological benign tumor and greatly affect reproductive health and well-being. They are the predominant indication for hysterectomy in premenopausal women. Current epidemiological study reported that soy products intake is inversely associated with diseases leading to hysterectomy. Genistein is a soy-derived phytoestrogen and its inhibitory effect on leiomyoma cell proliferation is reported. In this study, we investigated the siginificant inhibitory effect of genistein on estradiol (E2)-induced leiomyoma cells proliferation.Study design. The Eker rat-derived uterine leiomyoma cell line ELT-3 cells were used. Cell proliferation was assessed by counting the number of cells. The expression of estrogen receptors and peroxisome proliferator-activated receptor-γ (PPARγ) was evaluated by Western blot analysis.Results. PPARγ was expressed in ELT-3 cells and genistein acted as PPARγ ligand. This inhibitory effect of genistein was attenuated by the treatment of cells with PPARγ antagonist bisphenol A diglycidyl ether (BADGE) or GW9662.Conclusion. These experimental findings in vitro show that the repressive effect of genistein on E2-induced ELT-3 cell proliferation is through the activation of PPARγ. Genistein may be useful as an alternative therapy for leiomyoma.

Adverse effects of phytoestrogens on reproductive health: A report of three cases

Phytoestrogens have been thought to have favorable effects on women's health and perhaps in offsetting cancers. The possible adverse effects of phytoestrogens have not been evaluated. Abnormal uterine bleeding with endometrial pathology in three women was found to be related to a high intake of soy products. The first woman had postmenopausal bleeding with uterine polyp, proliferative endometrium and a growing leiomyoma. The second woman presented with severe dysmenorrhea, abnormal uterine bleeding, endometriosis and uterine leiomyoma not responding to treatment. The third woman with severe dysmenorrhea, abnormal uterine bleeding, endometriosis and uterine leiomyomata presented with secondary infertility. All three women improved after withdrawal of soy from their diet. Additional information on phytoestrogens is necessary to ascertain their safety before they can be routinely used as supplements.

Prostate cancer prevention

Prostate cancer is the most common male malignancy and the second or third leading cause of cancer death among men in the West. The descriptive epidemiology of prostate cancer suggests that it is a preventable disease. Prevention has the theoretical advantage of not only saving lives, but also reduce the morbidity of radical prostate cancer therapy. This article reviews the past, present, and future of prostate cancer prevention. In particular, the evidence and scientific data of a variety of prevention strategies are reviewed. Strategies reviewed include dietary fat reduction and supplementation with vitamins D and E, and selenium. Dietary intake of soy, green tea, and tomato-rich products (lycopene) are also reviewed. Data regarding pharmacological intervention with cyclo-oxygenease inhibitors, antiestrogens, and in particular 5-alpha reductase inhibitors are reviewed. The results of the Prostate Cancer Prevention Trial including the controversy surrounding higher-grade cancers among men randomized to finasteride are also summarized. Finally, a variety of trial designs as well as a roster of current phase 2 trials are presented. Probably no cancer is being investigated more thoroughly in the context of prevention as prostate cancer in 2007. Definitive answers to pivotal phase 3 trials will be available in the coming 2 to 7 years.

Soy Product Consumption and the Risk of Colon Cancer: A Prospective Study in Takayama, Japan

: The relationship of the intake of soy products and the incidence of colon cancer was prospectively evaluated in a population-based cohort study in Japan. The total intake of soy products and isoflavones in a daily diet was estimated from a validated questionnaire administered at the baseline. The participation rate of the questionnaire was 92.0%. The participants were followed from 1992 to 2000, and colon cancer diagnoses were identified at the main hospitals in the study area. In the analysis, 13,894 men and 16,327 women were included. The medians for energy-adjusted soy product intake were 85.52 g/day for men and 79.60 g/day for women. During follow-up, 111 men and 102 women were diagnosed with colon cancer. A Cox-proportional hazard model was applied to assess the risk of colon cancer incidence. Among women, the risk was reduced with an increased soy product consumption; the hazard ratio in the highest tertile was 0.56 (95% CI 0.34–0.92) compared as the lowest tertile (trend: P = 0.04), after adjusting for multiple potential confounders. Among men, no significant association was observed. Our results exhibited the weak benefit of soy foods only among women. Further research to confirm our results may be beneficial.

The Joint Effect of Oxidative Stress and Antioxidants on the Risk of an Aneurysmal Rupture Subarachnoid Hemorrhage: A Case-Control Study in Japan

A case-control study was conducted in Japan to examine the joint effects of oxidative stress and antioxidants on the risk of subarachnoid hemorrhage (SAH). The study included 201 consecutive patients with first spontaneous SAH aged 30 to 79 years who had aneurysm(s) confirmed by angiography and/or computed tomographic scan and were admitted to two medical hospitals in Nagoya, Japan, from April 1992 to March 1997. Community control subjects were identified and matched to each case by gender and age (+/-2 years). Conditional logistic regression modeling was used to compute odds ratios (ORs) adjusted for body mass index, physical activity, family history of SAH, a history of hypertension, drinking habit, and frequency of green-yellow vegetables and fruits, and tea consumption. The greatest risk for SAH was posed by combination of current smoking and a less frequent intake of soy products (adjusted OR = 5.3; 95% confidence interval [CI], 2.0 to 14.3). Less frequent intake of soy products significantly elevated SAH risk, independent of smoking habits. These data suggested that enhancement of the antioxidant defense system such as much intake of soy products may be important in preventing SAH rather than the reduction of such oxidants as smoking. Our findings should prove useful for targeting individuals/populations in programs for primary prevention of SAH.

Dietary Patterns Associated with Functional Constipation among Japanese Women Aged 18 to 20 Years: A Cross-Sectional Study

Although several nutrients and foods have been suggested to be preventive for constipation, all previous studies have examined a single nutrient or food in each analysis. In contrast, analysis of dietary patterns may provide new insights into the influence of diet on functional constipation. We conducted a cross-sectional examination of the association between dietary pattern and functional constipation in 3,770 Japanese female dietetic course students aged 18-20 y from 53 institutions in Japan. Diet was assessed with a validated self-administered diet history questionnaire with 148 food items, from which 30 food groups were created and entered into a factor analysis. Functional constipation was defined using the Rome I criteria, which has previously been used in several epidemiologic studies on constipation. The prevalence of functional constipation was 26.0% (n=979). Four dietary patterns were identified: (1) "Healthy", (2) "Japanese traditional", (3) "Western," and 4) "Coffee and dairy products." After adjustment for several confounding factors, the "Japanese traditional" pattern, characterized by a high intake of rice, miso soup, and soy products and a low intake of bread and confectionaries, was associated with a significantly lower prevalence of functional constipation. In comparison with the lowest quintile, the multivariate adjusted odds ratio (95% confidence interval) was 0.52 (0.41-0.66) in the highest quintile (p for trend < 0.0001). Other dietary patterns were not associated with functional constipation. The Japanese traditional dietary pattern, characterized by a high intake of rice and a low intake of bread and confectionaries, may be beneficial in preventing functional constipation in young Japanese women.

Soyfood Intake in the Prevention of Breast Cancer Risk in Women: A Meta-Analysis of Observational Epidemiological Studies

Many studies have suggested that the intake of soy products may protect against the occurrence of breast cancer because of the considerable amount of isoflavones they contain. To review the results of the observational studies, we performed this meta-analysis of the relevant literature. We searched Medline for reports that examined the association between soyfood consumption (or isoflavone intake) and breast cancer risk from January 1966 to April 2006. The random-effects model was used to estimate the pooled relative risk (RR). Twenty-one independent studies (14 case-control studies and 7 cohort studies) were included in the final analysis. The pooled RR of breast cancer for soyfood intake was 0.75 with a 95% CI of 0.59-0.95. As the main types of soyfood in Japan and China, tofu and miso showed clear protective effects. Isoflavone intake resulted in a 20% decrease in risk (RR = 0.81, 95% CI 0.67-0.99). The pooled RR varied little according to study stratification. When the studies published in Japanese and Chinese were added, the inverse associations between soyfood, tofu and breast cancer risk became slightly stronger. The weak association of miso was possibly due to the high concentration of salt in miso soup. In the present analysis, we did not find strong evidence for publication bias in the combination of the studies. This meta-analysis supported the hypotheses that soyfood intake may be associated with a decreased risk of breast cancer due to the isoflavones. Further epidemiological studies need to be conducted with more comprehensive information about the soyfood, and more accurate assessment of the isoflavones.

Genistein, a natural product from soy, is a potent inhibitor of transthyretin amyloidosis

The misfolding of transthyretin (TTR), including rate-limiting tetramer dissociation and partial monomer denaturation, is sufficient for TTR misassembly into amyloid and other abnormal quaternary structures associated with three amyloid diseases: senile systemic amyloidosis, familial amyloid polyneuropathy, and familial amyloid cardiomyopathy. Small molecules can bind to one or both of the unoccupied TTR thyroid hormone-binding sites, stabilizing the native tetramer more than the dissociative transition state, thereby raising the kinetic barrier for tetramer dissociation. Herein we demonstrate that genistein, the major isoflavone natural product in soy, works in this fashion and is an excellent inhibitor of transthyretin tetramer dissociation and amyloidogenesis, reducing acid-mediated fibril formation to <10% of that exhibited by TTR alone. Genistein also inhibits the amyloidogenesis of the most common familial amyloid polyneuropathy and familial amyloid cardiomyopathy mutations in TTR: V30M and V122I, respectively. Genistein additionally inhibits tetramer dissociation under physiological conditions thought to lead to slow amyloidogenesis in humans. Furthermore, this natural product exhibits highly selective binding to TTR in plasma over all of the other plasma proteins. Isothermal titration calorimetry shows that genistein binds to TTR with negative cooperativity (K(d1) = 40 nM, K(d2) = 1.4 microM). The benefits of using a nutraceutical such as genistein to treat orphan diseases such as the TTR amyloidoses include known oral bioavailability and safety data. It is conceivable that some patients could benefit from simply increasing their intake of soy products or supplements.

Recommended soy and soy products intake to prevent bone fracture and osteoporosis

Soy contains isoflavones, which are phytoestrogens, and its intake may help to prevent some diseases including menopausal disorder, osteoporosis, and breast cancer. Natto, a fermented soy product, is rich in vitamin K, which also contributes to bone health. In this report, we overviewed peer-reviewed papers showing relationship between soy product intake and risks of bone fracture and osteoporosis. It is suggested that that intake of soy products is not strongly enough to conclude but possible to be efficient in prevention of bone fracture and osteoporosis.