Isoflavone Intake Research Articles

Sojini izoflavoni kot pristop prve izbire pri zdravljenju vazomotoričnih težav v menopavzi

The link between higher uptake of isoflavones and a reduced frequency of menopause-related hot flushes were first described in 1992 based on a lower incidence of hot flushes in countries with high dietary soy intake1. Since then, a number of clinical trials with different sources of isoflavones, including soy and red clover, have been performed, and in almost all studies with an appropriate design the outcome was in favour of isoflavone supplementation2. A detailed risk assessment3 revealed that a number of data in humans do not confirm the alleged adverse effect resulting from possible interaction between isoflavones and the hormone-sensitive tissues of the mammary glands, uterus and thyroid. Safety was demonstrated by long-term intake of 150 mg of isoflavones per day, which lasted at least three years. It was also found that a high intake of isoflavones prevented the occurrence of breast cancer4-7. Clinical findings indicate potential benefits of exposure to isoflavones during breast cancer treatment with tamoxifen or anastrozole.

Relationship of serum levels and dietary intake of isoflavone, and the novel bacterium Slackia sp. strain NATTS with the risk of prostate cancer: a case-control study among Japanese men.

Isoflavones may play a role in the prevention of hormone-related cancers. Equol is an isoflavone metabolized from daidzein in the presence of certain intestinal bacteria. Slackia sp. strain NATTS, a newly identified equol-producing bacterium, was recently isolated from human feces in Japan. We investigated the association of serum levels and dietary intake of isoflavones and Slackia sp. strain NATTS with the risk of prostate cancer in a case-control study among Japanese men. Fifty-six patients with newly diagnosed prostate cancer and 56 hospital controls were enrolled in this study. Isoflavones were assessed by measurement of serum levels and administration of a food frequency questionnaire. Slackia sp. strain NATTS in feces was also measured. The odds ratios (ORs) and 95% confidence intervals (CIs) for prostate cancer were then determined using a logistic regression model. The adjusted ORs for prostate cancer in comparison with the highest to lowest categories were 0.06 (95% CI 0.02-0.24) for serum genistein, 0.18 (95% CI 0.06-0.52) for daidzein, 0.16 (95% CI 0.06-0.46) for glycitein, 0.52 (95% CI 0.22-1.22) for equol, 0.86 (95% CI 0.30-2.48) for dietary genistein, and 0.80 (95% CI 0.28-2.28) for dietary daidzein. The adjusted OR for prostate cancer in comparison with values above versus below the median was 0.95 (95% CI 0.42-2.16) for Slackia sp. strain NATTS. Our study findings suggest that high serum levels of genistein, daidzein, and glycitein are significantly associated with a decreased risk of prostate cancer among Japanese men.

Effects of Isoflavone-Enriched Feed on the Rumen Microbiota in Dairy Cows.

In this study, we compared the effects of two diets containing different isoflavone concentrations on the isoflavone transfer from feed into milk and on the rumen microbiota in lactating dairy cows. The on-farm experiment was conducted on twelve lactating Czech Fleckvieh x Holstein cows divided into two groups, each with similar mean milk yield. Twice daily, cows were individually fed a diet based on maize silage, meadow hay and supplemental mixture. Control group (CTRL) received the basal diet while the experimental group (EXP) received the basal diet supplemented with 40% soybean isoflavone extract. The average daily isoflavone intake in the EXP group (16 g/day) was twice as high as that in the CTRL group (8.4 g/day, P<0.001). Total isoflavone concentrations in milk from the CTRL and EXP groups were 96.89 and 276.07 μg/L, respectively (P<0.001). Equol concentrations in milk increased from 77.78 μg/L in the CTRL group to 186.30 μg/L in the EXP group (P<0.001). The V3-4 region of bacterial 16S rRNA genes was used for metagenomic analysis of the rumen microbiome. The experimental cows exhibited fewer OTUs at a distance level of 0.03 compared to control cows (P<0.05) and reduced microbial richness compared to control cows based on the calculated Inverse Simpson and Shannon indices. Non-metric multidimensional scaling analysis showed that the major contributor to separation between the experimental and control groups were changes in the representation of bacteria belonging to the phyla Bacteroidetes, Proteobacteria, Firmicutes, and Planctomycetes. Surprisingly, a statistically significant positive correlation was found only between isoflavones and the phyla Burkholderiales (r = 0.65, P<0.05) and unclassified Betaproteobacteria (r = 0.58, P<0.05). Previous mouse and human studies of isoflavone effects on the composition of gastrointestinal microbial populations generally report similar findings.

Removing isoflavones from modern soyfood: Why and how?

Estrogenic isoflavones were found, in the 1940s, to disrupt ewe reproduction and were identified in soy-consumers’ urine in 1982. This led to controversy about their safety, often supported by current Asian diet measurements, but not by historical data. Traditional Asian recipes of soy were tested while assaying soy glycosilated isoflavones. As these compounds are water-soluble, their concentration is reduced by soaking. Pre-cooking or simmering time-dependently reduces the isoflavone:protein ratio in Tofu. Cooking soy-juice for 15 or 60min decreases the isoflavone:protein ratios in Tofu from 6.90 to 3.57 and 1.80, respectively (p<0.001). Traditional Tempeh contains only 18.07% of the original soybean isoflavones (p<0.001). Soy-juice isoflavones were reduced by ultra-filtration (6.54 vs 1.24 isoflavone:protein; p<0.001). Soy-protein and isoflavones are dissociated by water rinsing and prolonged cooking, but these have no equivalent in modern processes. As regards human health, a precise definition of the safety level of isoflavone intake requires additional studies.

Soy isoflavone intake is associated with risk of Kawasaki disease

Kawasaki disease (KD) is an acute vasculitis affecting children. Incidence of KD varies according to ethnicity and is highest in Asian populations. Although genetic differences may explain this variation, dietary or environmental factors could also be responsible. The objectives of this study were to determine dietary soy and isoflavone consumption in a cohort of KD children just before disease onset and their mothers' intake during pregnancy and nursing. We tested the hypothesis that soy isoflavone consumption is associated with risk of KD in US children, potentially explaining some of the ethnic-cultural variation in incidence. We evaluated soy food intake and isoflavone consumption in nearly 200 US KD cases and 200 age-matched controls using a food frequency questionnaire for children and in their mothers. We used a logistic regression model to test the association of isoflavones and KD. Maternal surveys on soy intake during pregnancy and nursing showed no significant differences in isoflavone consumption between groups. However, we identified significantly increased KD risk in children for total isoflavone (odds ratio [OR], 2.33; 95% confidence interval [CI], 1.37-3.96) and genistein (OR, 2.46; 95% CI, 1.46-4.16) intakes, when comparing high soy consumers vs nonconsumers. In addition, significantly increased KD risk occurred in Asian-American children with the highest consumption (total isoflavones: OR, 7.29; 95% CI, 1.73-30.75; genistein: OR, 8.33; 95% CI, 1.92-36.24) compared to whites. These findings indicate that childhood dietary isoflavone consumption, but not maternal isoflavone intake during pregnancy and nursing, relates to KD risk in an ethnically diverse US population.

Dietary Flavonoid Intake Is Negatively Associated with Anthropometric Risk Factors for Chronic Disease in Some Population Subgroups But Not Others: Results from What We Eat in America, NHANES 2007–2010

Flavonoids, bioactive compounds found in plants, are considered beneficial for human health. Whereas favorable associations between flavonoid intakes and anthropometric measures that are risk factors for chronic disease have been found in various studies, little research has examined whether similar associations exist in the U.S. population overall or in specific racial/ethnic groups. The purpose of this study was to investigate whether flavonoid intake is related to body mass index (BMI) and waist circumference (WC) in a large, nationally representative sample of U.S. adults. Data from one 24‐hour recall for 5,378 males and 5,480 non‐pregnant, non‐lactating females age 20 years and over participating in What We Eat in America (WWEIA), NHANES 2007–2010 were analyzed. Intakes of total flavonoids and six flavonoid classes (anthocyanidins, flavan‐3‐ols, flavanones, flavones, flavonols, and isoflavones) were determined by applying the recently released, comprehensive database Flavonoid Values for USDA Survey Foods and Beverages 2007–2008. The few plant‐based foods/beverages that were new in the 2009–2010 survey were assigned the flavonoid profile of the most similar 2007–2008 item. For total flavonoids and for each class, individuals were divided into four categories of intake, and trends in BMI and WC were determined using orthogonal polynomial contrasts with adjustment for confounding variables. For all adults age 20 years and over, negative trends in both BMI and WC were found with increasing category of intake of total flavonoids, anthocyanidins, flavan‐3‐ols, and flavanones (p&lt;0.001). Identical trends were seen among men, but only anthocyanidins and flavanones were inversely associated with BMI and WC among women. No significant associations were found between anthropometric measures and intakes of flavones, flavonols, or isoflavones. Among non‐Hispanic (NH) whites (both genders together), inverse associations were found between WC and total flavonoid intake and between both BMI and WC and intakes of anthocyanidins, flavan‐3‐ols, and flavanones. Among Hispanics, inverse associations were found between both BMI and WC and anthocyanidin intake. Among NH blacks, no relationships were identified between anthropometric measures and flavonoid intakes. Negative associations between flavonoid intake and BMI and WC are not uniform across flavonoid classes, gender, or race/ethnicity. The finding of significant negative associations between flavonoid intakes and BMI and WC in some populations but not others suggests that further examination by race/ethnicity of intake of flavonoids and flavonoid‐containing foods/beverages might contribute to understanding of disparities in chronic disease occurrence.Support or Funding InformationARS, USDA

Dietary Intake of Isoflavone and All‐Cause Mortality in Women with Breast Cancer: the Breast Cancer Family Registry

Dietary Intake of Isoflavone and All‐Cause Mortality in Women with Breast Cancer: the Breast Cancer Family Registry

Soy Consumption with Risk of Coronary Heart Disease and Stroke: A Meta-Analysis of Observational Studies

Background: The association of soy product consumption with the relative risk of cardiovascular disease remains controversial. This meta-analysis aimed at investigating whether an association exists between soy consumption and the risk of stroke and coronary heart disease (CHD) in observational studies. Methods: A systematic search of the PubMed and EMBASE databases was performed for case-control and cohort studies that assessed soy consumption and the risk of stroke and CHD. Summary relative risks (SRRs) and 95% CIs were combined by using a random-effects model. Results: Of a total of 1,266 abstracts, 5 prospective cohort and 6 case-control studies met our inclusion criteria, and comprised 4,954 stroke and 7,616 CHD events. Based on the high vs. low analyses, combining cohort studies showed no association between soy intake and risk of stroke (SRR 0.92; 95% CI 0.70-1.10; P_{heterogeneity} = 0.236; I² = 29.4%) or CHD (SRR 0.97; 95% CI 0.74-1.27; P_{heterogeneity} = 0.020; I² = 62.7%), although a significantly inverse association between soy intake and the risk of stroke (SRR 0.54; 95% CI 0.34-0.87; P_{heterogeneity} = 0.001; I² = 79.3%) and CHD (SRR 0.66; 95% CI 0.56-0.77; P_{heterogeneity} = 0.421; I² = 0) was observed in case-control studies. No association between soy isoflavone intake and the risk of stroke and CHD was identified. Conclusion: There was limited evidence to indicate that soy consumption was inversely associated with the risk of stroke and CHD, although further studies, with prospective designs that use validated questionnaires and control for important confounders, are warranted.

Greater flavonoid intake is associated with improved CVD risk factors in US adults.

Epidemiological studies have reported that diets high in flavonoids are associated with a reduced risk of CVD. However, evidence on the association of dietary flavonoid intake with CVD risk factors is still scarce. The present study aimed to investigate the association of dietary flavonoid intake with CVD risk factors among US adults in the National Health and Nutrition Examination Survey (NHANES) 2007-2012. A total of 4042 US adults aged 19 years and older from the NHANES 2007-2012 participated in this cross-sectional, population-based study. Intakes of total and individual flavonoids were estimated from 2-d 24-h diet recall data by matching with the expanded US Department of Agriculture flavonoid, isoflavone and proanthocyanidin databases. After adjusting for covariates, increased HDL-cholesterol was associated with higher total flavonoid intake (0·54 % change). TAG and TAG:HDL-cholesterol ratio were inversely associated with anthocyanidin (-1·25 % change for TAG; -1·60 % change for TAG:HDL-cholesterol ratio) and total flavonoid intakes (-1·31 % change for TAG; -1·83 % change for TAG:HDL-cholesterol ratio), respectively. Insulin and homoeostasis model assessment for insulin resistance (HOMA-IR) were inversely associated with flavone (for insulin, -3·18 % change; 95 % CI -5·85, -0·44; for HOMA-IR, -3·10 % change; 95 % CI -5·93, -0·19) and isoflavone intakes (for insulin, -3·11 % change; 95 % CI -5·46, -0·70; for HOMA-IR, -4·01 % change; 95 % CI -6·67, -1·27). BMI was negatively associated with anthocyanidin intake (-0·60 % change). This study showed that higher flavonoid intake was associated with improved CVD risk factors. Further research is warranted to confirm the findings from this study as these associations were moderate in strength.

Abstract P3-09-03: Combined effects of soy isoflavones and a high fat diet on the mammary gland in an animal model of diet-induced obesity

Abstract Scope: Obesity is a major risk factor for the development of breast cancer whereas isoflavone (ISO) exposure is discussed to reduce this risk. Aim of this study was to investigate effects of dietary soy ISO intake on proliferation and estrogenicity of ISO in the mammary gland of obese female Wistar rats. Methods: Female Wistar rats (5 – 7 rats / group) grew up on low fat ISO-depleted diet (LF IDD) or ISO-rich diet enriched with a soy based commercial extract (LF IRD; ISO: 467 mg / kg diet). Starting postnatal day 83, ovariectomized (OVX) and intact animals received high fat diet for 12 weeks to induce obesity in the absence (HF IDD) or presence of ISO (HF IRD, ISO: 431 mg / kg diet). A special diet switch group (HF IRD switch OVX), grew up on LF IDD but switched to HF IRD after ovariectomy. This mimics the short term exposure to ISO in postmenopausal Western women who take ISO supplements. Two groups receiving LF diet either with or without ISO (LF IRD, LF IDD) lifelong served as control. From ablactation until the end of the experiment body weight and food consumption were monitored twice a week. After 12 weeks of HF diet animals were sacrificed. Body weight, visceral fat mass, and serum leptin were measured, and breast tissue was excised. Protein expression of proliferating cell nuclear antigen (PCNA) and progesterone receptor (PR) in breast tissue was analyzed by both immunohistochemistry (IHC) and Western Blot as markers for proliferation and estrogenicity of ISO, respectively. Results: Analysis of ISO plasma levels revealed 1400 nM in LF IRD group and 300 – 700 nM in HF IRD groups. HF diet increased body weight, visceral fat mass and serum leptin levels compared to LF diet. In the mammary gland HF increased expression of proliferation marker PCNA and PR as compared to LF groups. Lifelong but not short term (HF IRD switch OVX) ISO exposure reduced body weight, visceral fat mass and leptin levels in HF OVX rats. In the mammary gland lifelong ISO exposure reduced PCNA expression in both LF and HF intact animals whereas in HF OVX animals lifelong ISO exposure increased PCNA expression compared to short term ISO exposure. PR expression increased in HF IRD OVX compared to HF IDD OVX. Conclusion: The ISO plasma levels of the rats are comparable to the average ISO plasma levels as found in Asian population. Our results show that lifelong ISO intake reduces the risk to develop obesity in female rats. In the mammary gland lifelong ISO exposure decreases cell proliferation and shows estrogenicity by increasing PR expression. Effects of short term ISO exposure are less strong compared to lifelong ISO exposure. This supports the hypothesis that only lifelong but not short term ISO exposure can reduce the risk to develop breast cancer. Citation Format: Kurrat A, Diel P, Blei T, Kluxen F, Mueller D, Pichotta M, Soukup S, Kulling S, Oden C. Combined effects of soy isoflavones and a high fat diet on the mammary gland in an animal model of diet-induced obesity. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-09-03.

Soy isoflavone exposure through all life stages accelerates 17β-estradiol-induced mammary tumor onset and growth, yet reduces tumor burden, in ACI rats.

There is an ongoing debate whether the intake of soy-derived isoflavones (sISO) mediates beneficial or adverse effects with regard to breast cancer risk. Therefore, we investigated whether nutritional exposure to a sISO-enriched diet from conception until adulthood impacts on 17β-estradiol (E2)-induced carcinogenesis in the rat mammary gland (MG). August-Copenhagen-Irish (ACI) rats were exposed to dietary sISO from conception until postnatal day 285. Silastic tubes containing E2 were used to induce MG tumorigenesis. Body weight, food intake, and tumor growth were recorded weekly. At necropsy, the number, position, size, and weight of each tumor were determined. Plasma samples underwent sISO analysis, and the morphology of MG was analyzed. Tumor incidence and multiplicity were reduced by 20 and 56%, respectively, in the sISO-exposed rats compared to the control rats. Time-to-tumor onset was shortened from 25 to 20weeks, and larger tumors developed in the sISO-exposed rats. The histological phenotype of the MG tumors was independent of the sISO diet received, and it included both comedo and cribriform phenotypes. Morphological analyses of the whole-mounted MGs also showed no diet-dependent differences. Lifelong exposure to sISO reduced the overall incidence of MG carcinomas in ACI rats, although the time-to-tumor was significantly shortened.

Genetic polymorphisms of insulin-like growth factor 1 and insulin-like growth factor binding protein 3, xenoestrogen, phytoestrogen, and premenopausal breast cancer.

Previous studies suggest a combined effect of insulin-like growth factor 1 (igf-1) and igf binding protein 3 (igfbp-3) gene polymorphisms, xenoestrogen, and phytoestrogen on the igf-1 signalling pathway and serum concentrations in the igf system, which are associated with premenopausal breast cancer (bca) risk. Between 2010 and 2012, our study recruited 140 premenopausal bca patients and 160 community-based premenopausal control subjects. Participants were surveyed about oral contraceptive (oc) use, dietary habits, and other bca risk factors. TaqMan assays were used to determine igf-1 rs1520220 and igfbp-3 rs2854744 genotypes. Daily intakes of energy-adjusted soy isoflavones (easis) were calculated by the residual method. Multivariate logistic regression was applied to estimate the adjusted odds ratios (ors) and 95% confidence intervals (cis) of the igf-1 rs1520220 and igfbp-3 rs2854744 genotypes, oc use, and intake of easis. Stratified analyses were performed to detect the gene-environment combined effect, and multivariate logistic regression was used to estimate interaction coefficients (iors) by the multiplicative model, with 95% cis. The delta method was used to calculate interaction coefficients by the additive model [relative excess risk of interaction (reri), attributable proportions of interaction (apis)] and 95% cis. The igf-1 and igfbp-3 genotypes, oc use, and easis were not found to be associated with bca risk (p > 0.05). Stratified analysis showed that the risk of bca was markedly increased in women carrying the igfbp-3C allele and using ocs compared with women either carrying the igfbp-3C allele or using ocs (or: 3.02; 95% ci: 1.04 to 8.79). The interaction coefficients ior, reri, and api were 4.89 (95% ci: 1.09 to 21.90), 2.42 (95% ci: -0.76 to 5.61), and 0.80 (95% ci: 0.46 to 1.67) respectively. The igfbp-3 rs2854744 polymorphism and oc use might synergistically increase premenopausal bca risk.

Equol Effectively Inhibits Toxic Activity of Human Neutrophils without Influencing Their Viability

Equol (7,4′-dihydroxy-isoflavan, or 4′,7-isoflavandiol) is a chroman derivative produced by intestinal bacteria in response to soy isoflavone intake in some, but not in all, humans. Equol shows strong anti-oxidant, anti-estrogenic, anti-cancerous and anti-inflammatory properties. The antioxidative capacity of equol has recently received considerable attention, and it has been used for preventing and treating several diseases. We investigated the effect of equol on human neutrophils, extra- and intracellular formation of oxidants, the phosphorylation of protein regulating NADPH oxidase and its effect on apoptosis. Neutrophils, isolated from blood from healthy subjects, were tested upon activation with various stimulants, proper for reactive oxygen species (ROS) production and treated by equol. Equol has the ability to reduce the toxic action of neutrophils. With increasing concentrations, equol decreased the amount of oxidants produced by neutrophils both extra- and intracellularly. The phosphorylation of p40^phox (a component of NADPH oxidase, responsible for the assembly of functional oxidase in intracellular membranes) was reduced in the presence of equol. The experiments showed that equol did not change the number of viable, apoptotic or dead neutrophils significantly in all concentrations used. These results indicate the promising effect of equol in the operation of ROS in different mechanisms in the model of inflammation.

Dietary Total Isoflavone Intake Is Associated With Lower Systolic Blood Pressure: The Coronary Artery Risk Development in Young Adults (CARDIA) Study.

The effect of dietary isoflavone intake on systolic blood pressure (SBP) has not been studied in a large community-based cohort inclusive of African Americans. The authors analyzed data from the year 20 examination of the Coronary Artery Risk Development in Young Adults (CARDIA) study, including medical history, physical examination, and dietary intake surveys for 3142 participants. Multivariable linear regression models controlled for age, sex, body mass index, smoking, physical activity, and intakes of alcohol and total energy. Effect modification by race was tested. Overall, patients with hypertension had a lower daily intake of total dietary isoflavones (2.2±5.2 mg/d vs 4.1±11.7 mg/d; P<.001). In fully adjusted models, the highest quartile of dietary isoflavone intake was associated with a 4.4 mm Hg lower SBP on average compared with SBP for the lowest quartile. The relationship between dietary isoflavone intake and SBP was more pronounced among African Americans compared with Caucasians (P for interaction <.001). Greater dietary intake of isoflavones was independently associated with a lower SBP.

Diets High in Fiber and Vegetable Protein Are Associated with Low Lumbar Bone Mineral Density in Young Athletes with Oligoamenorrhea

BackgroundAssociations of bone mineral density (BMD) with specific food components, including dietary fiber and isoflavones (that have a negative association with serum estrogen), are unclear and need to be determined, particularly in populations more likely to consume large amounts of these nutrients (such as young athletes). ObjectiveTo determine dietary intake of specific food components in athletes with oligoamenorrhea (OA) compared to athletes with eumenorrhea (EA) and nonathletes (NA), and associations of the dietary intake of these nutrients with lumbar spine BMD. Design and subjectsThis cross-sectional study evaluated 68 OA, 24 EA, and 26 NA individuals aged 14 to 23 years. Measurements included 4-day food records, a dual x-ray absorptiometry scan evaluating lumbar spine BMD and body composition, and hormone levels. Multivariate analysis was used to estimate associations of nutrients with lumbar spine BMD. ResultsCompared with EA and NA, OA had higher intake of fiber, phytic acid, and vegetable protein (all P values <0.0001). Intake of isoflavones, genistein, and daidzein was higher in OA than NA (P=0.003 and P=0.0002, respectively). OA had lower consumption of energy from saturated fatty acids than NA (P=0.002). After controlling for confounders such as body weight, menstrual status (indicative of estrogen status), calcium intake, and serum vitamin D (known BMD determinants), lumbar spine BMD z scores were inversely associated with dietary fiber (β=–.30; P=0.01), vegetable protein (β= –.28; P=0.02), phytic acid (β=–.27; P=0.02), genistein (β=–.25; P=0.01), and daidzein (β=–.24; P=0.01), and positively associated with percent energy from fatty acids (β=.32; P=0.0006). ConclusionsCompared with EA and NA, OA had a higher dietary intake of fiber, vegetable protein, and phytic acid, which were inversely associated with lumbar spine BMD z scores. Further studies are needed to assess dietary recommendations for OA to optimize bone accrual.

Relationship between daily isoflavone intake and sleep in Japanese adults: a cross-sectional study.

BackgroundIsoflavones comprise a class of phytoestrogens that resemble human estrogen in chemical structure, and have weak estrogenic effects. Because estrogen modulates sleep duration and quality, we hypothesized that isoflavones would have a beneficial effect on sleep status in a way similar to estrogen. We conducted a cross-sectional study to investigate the relationship between daily isoflavone intake and sleep status in Japanese subjects.MethodsOur study included 1076 Japanese adults aged 20-78 years. Daily isoflavone intake was assessed using a brief self-administered diet history questionnaire, and sleep was evaluated using a self-reported questionnaire.ResultsThe prevalence of regular sleep duration (7–8 h/day) and sufficient sleep quality were 13.3 % and 56.2 %, respectively. After adjusting for potential confounding factors, the odds ratios (95 % CIs) for optimal sleep duration (7–8 h) when higher isoflavone intakes (Q2–Q4) were compared with low isoflavone intake (Q1) were Q2: 0.94 (0.53–1.56); Q3: 1.28 (0.73–2.24); and Q4: 1.84 (1.06–3.18) (p for trend = 0.013). In the final adjusted model, sufficient sleep quality across categories of isoflavone intake was Q1: 1.00 (reference); Q2: 1.30 (0.91–1.84); Q3: 1.48 (1.03–2.12); and Q4: 1.78 (1.22–2.60); (p for trend = 0.002).ConclusionHigher daily isoflavone intake was positively associated with optimal sleep duration and quality in a Japanese population. This finding suggests that daily isoflavone intake may have a potentially beneficial effect on sleep status.

Isoflavone and Soyfood Intake and Colorectal Cancer Risk: A Case-Control Study in Korea.

We aimed to assess the relationship between dietary soyfood and isoflavone intake and colorectal cancer risk in a case-control study. A total of 901 colorectal cancer cases and 2669 controls were recruited at the National Cancer Center, Korea. A semi-quantitative food frequency questionnaire was used to assess the usual dietary habits, and the isoflavone intake level was estimated from five soyfood items. A high intake of total soy products, legumes, and sprouts was associated with a reduced risk for colorectal cancer in men and women, although the middle quartiles of intake of total soy products were associated with an elevated risk. In contrast, a high intake of fermented soy paste was associated with an elevated risk for colorectal cancer in men. The groups with the highest intake quartiles of isoflavones showed a decreased risk for colorectal cancer compared to their counterparts with the lowest intake quartiles in men (odds ratio (OR): 0.67, 95% confidence interval (CI): 0.51–0.89) and women (OR: 0.65, 95% CI: 0.43–0.99). The reduced risk for the highest intake groups persisted for distal colon cancer in men and rectal cancer in women. The association between soyfood intake and colorectal cancer risk was more prominent among post-menopausal women than pre-menopausal women. In conclusion, a high intake of total soy products or dietary isoflavones was associated with a reduced risk for overall colorectal cancer, and the association may be more relevant to distal colon or rectal cancers.

Dietary isoflavone intake is associated with a reduced risk of myelodysplastic syndromes.

Isoflavones have been suggested to have protective effects on certain cancers. However, the association of soya foods or dietary isoflavones with the risk of myelodysplastic syndromes (MDS) has not been examined. Thus, the aim of this hospital-based case-control study undertaken in China in 2012-2013 was to investigate the association between dietary isoflavone intake and MDS risk. The analysis included 208 cases aged 19-85 years with MDS and 208 controls individually matched to the cases by sex, birth quinquennium and residential locality. Information on habitual food intakes, including nine items of soya foods, was sought from in-person interviews using a validated 107-item FFQ. Dietary intakes of daidzein, genistein, glycitein and total isoflavones were estimated using the 2008 US Department of Agriculture Isoflavone Database. OR were calculated from conditional logistic regression after adjustment for potential confounding by demographics, lifestyle and dietary factors. The mean daily intake of total isoflavones was 19·0 mg in cases and 23·0 mg in controls. Dietary intake of isoflavones was inversely associated with the risk of MDS. The adjusted OR in the highest tertile compared with the lowest tertile of intake were 0·43 (95 % CI 0·21, 0·85) for daidzein, 0·36 (95 % CI 0·18, 0·74) for genistein, 0·49 (95 % CI 0·25, 0·97) for glycitein and 0·40 (95 % CI 0·20, 0·81) for total isoflavones. The findings suggest that higher dietary intake of isoflavones is associated with a reduced risk of MDS in a Chinese population.

The association between soya consumption and serum thyroid-stimulating hormone concentrations in the Adventist Health Study-2.

Consumers may choose soya foods as healthful alternatives to animal products, but concern has arisen that eating large amounts of soya may adversely affect thyroid function. The present study aimed to examine the association between soya food consumption and serum thyroid-stimulating hormone (TSH) concentrations in North American churchgoers belonging to the Seventh-day Adventist denomination that encourages vegetarianism. Participants completed six repeated 24 h dietary recalls within a 6-month period. Soya protein and soya isoflavone intakes were estimated, and their relationships to TSH concentrations measured at the end of 6 months were calculated using logistic regression analyses. Calibration sub-study of the Adventist Health Study-2. Women (n 548) and men (n 295) who were not taking thyroid medications. In men, age and urinary iodine concentrations were associated with high serum TSH concentrations (>5 mIU/l), while among women White ethnicity was associated with high TSH. In multivariate models adjusted for age, ethnicity and urinary iodine, soya isoflavone and protein intakes were not associated with high TSH in men. In women higher soya isoflavone consumption was associated with higher TSH, with an adjusted odds ratio (highest v. lowest quintile) of 4·17 (95 % CI 1·73, 10·06). Likewise, women with high consumption of soya protein (midpoint of highest quintile, 11 g/d) v. low consumption (midpoint of lowest quintile, 0 g/d) carried increased odds of high TSH (OR=2·69; 95 % CI 1·34, 5·30). In women high consumption of soya was associated with elevated TSH concentrations. No associations between soya intake and TSH were found in men.

Lifelong exposure to dietary isoflavones reduces risk of obesity in ovariectomized Wistar rats.

Traditional Asian diet rich in soy isoflavones (ISOs) is discussed to be linked to a lower obesity prevalence. In lifelong and short-term exposure scenarios we investigated effects of an ISO-rich diet on the body composition and development of obesity in female rats. Female Wistar rats grew up on ISO-free or ISO-rich control diet (CON ISO: 467 mg/kg diet). Starting postnatal day 83, ovariectomized and intact animals received high calorie Western diet (WD) in the absence or presence of ISO (WD ISO: 431 mg/kg diet) for 12 weeks to induce obesity or maintained on respective control diet (CON). One group starting ISO exposure after ovariectomy mimics short-term ISO exposure in postmenopausal Western women. Lifelong but not short-term ISO exposure resulted in reduced body weight, visceral fat mass, serum leptin, and smaller adipocytes. ISO decreased hepatic SREBP-1c, ACC, FAS, and PPARγ mRNA expression in nonobese animals. Moreover, ovariectomy reduced skeletal muscle weight, which was antagonized by both short-term and lifelong ISO exposure. Our results indicate that in female rats lifelong but not short-term ISO intake reduces the risk to develop obesity. Furthermore, lifelong and short-term ISO exposure may antagonize loss of skeletal muscle mass induced by ovariectomy.