Comparison of the five different definitions of equol producers: The relationship between blood and urine equol concentrations and blood parameters in 466 healthy men and women.

BACKGROUND AND AIMS: No studies have compared various definitions of "equol producers" until now. Therefore, we aimed to explore the accuracy of five different definitions of equol producers (EQP) and their associations with health benefits. METHODS: This is a cross-sectional study of 466 healthy Japanese men and women aged between 22 and 88 years. Equol producer proportions were calculated from their serum and urine isoflavone concentrations using five commonly used definitions. We then examined their accuracy, and associations with the blood parameters. RESULTS: Proportions of equol ranged from 29 % in the most stringent definition to 47.6 % in the most sensitive definition. EQP identified under all definitions had significantly low serum PSA1 levels compared to nonequol producers (NEQP). The most stringent definition, which is defined as the urinary equol level of 1.0 µM and above, corresponded to the highest median serum equol level and was associated with better health outcomes. Male EQP identified by this definition seemed to have reduced risk of LDL2-hypercholesterolemia by 50 %, and female EQP identified by this definition seemed to have lower risk of high hs-CRP,3 compared to NEQP. Both the first and second stringent definition, which is defined as the serum equol level of 1.0 ng/mL and above, was associated with lower thyroid stimulating hormone level. CONCLUSIONS: More stringent definitions were associated with better parameters in general. Combined with the dietary inquires, a reliable definition for equol producer is crucial to evaluate the health benefits of equol.

Association between equol producers and type 2 diabetes mellitus among Japanese older adults.

AIMS/INTRODUCTION: Equol, which is produced by enteric bacteria from soybean isoflavones, has a chemical structure similar to estrogen. Both in vivo and in vitro studies have shown the beneficial metabolic effects of equol. However, its effects on type 2 diabetes remain unclear. We investigated the association between the equol producers/non-producers and type 2 diabetes. MATERIALS AND METHODS: The participants included 147 patients with type diabetes mellitus aged 70-89 years, and 147 age- and sex-matched controls. To ascertain the equol producers or non-producers, we used the comparative logarithm between the urinary equol and daidzein concentrations (cut-off value -1.75). RESULTS: The urinary equol concentration was significantly lower in the diabetes group compared with the non-diabetes group (P = 0.01). A significant difference in the proportion of equol producers was observed among all participants (38.8% in the diabetes group and 53.1% in the non-diabetes group; P = 0.01). The proportion of equol producers among women was significantly lower in the diabetes group (31.4%) than in the non-diabetes group (52.8%; P < 0.01). Additionally, the frequency of dyslipidemia in female equol producers was significantly lower than that in female non-equol producers (P < 0.01). Among men, no such differences were observed. We found a significant positive correlation between the urinary equol and daidzein concentrations among equol producers (r = 0.55, P < 0.01). CONCLUSIONS: Our study findings showed that postmenopausal women had a low proportion of equol producers with diabetes and dyslipidemia.

Grading of Japanese Diet Intakes by 24-Hour Urine Analysis of Taurine and Soy Isoflavones in Relation to Cardiovascular Risks.

To investigate the association of the Japanese diet with risks for lifestyle-related diseases, the biomarkers of seafood and soybean consumption, taurine (T) and soy isoflavones (I), and others were analyzed in 24-hour urine (24U) samples collected from participants of the Cardiovascular Diseases and Alimentary Comparison (CARDIAC) Study coordinated by the World Health Organization (WHO). The data of T and I normalized for creatinine content in 24U were divided into five quintiles, T1 to T5, and I1 to I5. The total data of the collected samples were divided into 25 groups, which were obtained by 5 (T1-T5) × 5 (I1-I5) according to 24U excretions of T and I corresponding to the intake of seafood and soybeans from the least to the highest, respectively. Since these two nutrients were often consumed together in the Japanese diet, this characteristic was expressed as J1 to J5 based on the amounts of 24U T and I excretions. The risks for lifestyle-related diseases, obesity (body mass index, BMI), and cholesterolemia became lower during the transition from J1 to J5, while HDL cholesterol levels became higher from J1 to J5. On the contrary, urinary salt excretion and the sodium (Na)/potassium (K) ratio became higher from J1 to J5. Systolic blood measure was significantly lower in J3 than in J5. Diastolic blood pressure was also significantly lower in J3 than in J1. In conclusion, the higher the J score, which corresponds to Japanese dietary habits, the lower the BMI and cholesterol levels, as well as mortality rate from coronary heart disease, but the higher the average life expectancy among the Japanese. However, these higher J scorings were associated with high-salt intake and high Na/K ratios; therefore, they contributed to high blood pressure and high mortality rate caused by stroke in Japan. These results indicate that low-salt intake should be recommended to the Japanese who are consuming seafood and soy regularly in order to maintain lower blood pressure and to extend healthy life expectancy with a lower risk of stroke. Moreover, high scorings of the Japanese diet correspond to the high intake of magnesium (Mg) which is rich in seafood including seaweeds and soy. Therefore, low-salt seafood and soy intake is expected to reduce the incidence of the metabolic syndrome, the risk of which is inversely related to T and Mg intake.

Urinary Phytoestrogen Levels Are Associated with Female Hormonal Cancers: An Analysis of NHANES Data From 1999 to 2010.

Phytoestrogens are plant-derived compounds that are structurally similar to endogenous estrogens. Studies have shown phytoestrogens to have possible health benefits although they could also act as endocrine disruptors. This is particularly relevant for estrogen-dependent cancers since estrogens increase risk of breast, endometrial, and ovarian cancer. Using data from the National Health and Nutritional Examination Survey (NHANES), we assessed the associations between urinary phytoestrogens (daidzein, equol, o-Desmethylangolensin (O-DMA), genistein, enterodiol, enterolactone) and breast, endometrial, and ovarian cancer using multivariate logistic regression with odds ratios (ORs) and 95% confidence intervals (CIs). Cancer diagnosis and other characteristics were collected via in-person questionnaires. We found women in the highest tertile for daidzein and enterodiol had over twice the odds of having breast cancer (OR = 2.51, 95% CI 1.44-4.36 for daidzein, OR = 2.78, 95% CI 1.44-5.37 for enterodiol). In addition, women in the highest tertiles for daidzein and genistein had three to four times the odds of having endometrial cancer, respectively (OR = 3.09, 95% CI 1.01-9.49 for daidzein, OR = 4.00, 95% CI 1.38-11.59 for genistein). Overall, phytoestrogens were positively associated with breast and endometrial cancer although the associations varied by phytoestrogen type. Additional studies are needed to further inform phytoestrogens' role in disease etiology.Supplemental data for this article is available online at at https://doi.org/10.1080/01635581.2021.2020304.

Urinary equol levels are positively associated with urinary estradiol excretion in women.

Isoflavones found in soy products are a promising class of nutrients that may have a positive effect on human health. In particular, the phytoestrogen metabolite equol is associated with a reduced risk of developing female hormone-related diseases. However, the effect of equol on estrogen remains unclear. Equol can modify blood and urinary estradiol (E2) levels. The aim of this cross-sectional study was to examine the associations between urinary estrogen levels, equol levels, and equol production status in Japanese women. We analyzed urine samples from 520 women by gas chromatography-mass spectrometry. Urinary E2 and 4-hydroxylated E2 levels were higher in equol producers (EQP) than in non-EQPs (P < 0.0001 and P=0.00112, respectively). After adjusting for age and tobacco use by analysis of covariance, the association remained significant (ß = 0.299, P < 0.0001). Analysis of covariance demonstrated that equol levels in urine were also positively associated with urinary E2 (ß = 0.597, P < 0.0001). The log equol concentration showed a significant, but moderate, negative association with the serum E2 concentration (ß = - 0.0225, P = 0.0462). Our findings suggest that equol may promote urinary E2 excretion and modify blood E2 levels in women.

A Non-Probiotic Fermented Soy Product Reduces Total and LDL Cholesterol: A Randomized Controlled Crossover Trial.

Traditional Asian fermented soy food products are associated with reduced cardiovascular disease risk in prospective studies, but few randomized controlled trials have been conducted in at-risk populations. The aim of this study was to investigate the effect of a commercial non-probiotic fermented soy product on blood lipids in adults with cardiovascular risk biomarkers. In a randomized, crossover, intervention study, 27 men and women (aged 29-75 y) exhibiting at least two risk factors, consumed two packets (12.5 g each) daily of a fermented powdered soy product, or an isoenergic control powder made from germinated brown rice for 12 weeks each. The consumption of the fermented soy product resulted in a significantly greater mean change from baseline (compared to the germinated rice, all p < 0.05) in total cholesterol of -0.23 mmol/L (CI: -0.40, -0.06) compared with 0.14 mmol/L (CI: -0.03, 0.31), respectively; and low density lipoprotein (LDL) cholesterol -0.18 mmol/L (CI: -0.32, -0.04) compared with 0.04 mmol/L (CI: -0.01, 0.018) respectively. This was accompanied by an increase in high density lipoprotein (HDL) cholesterol in the germinated rice group, a decrease in apolipoprotein B (ApoB) in the fermented soy group, and a between-treatment effect in apolipoprotein A1 (ApoA1); however, the ratio of the LDL:HDL and of Apo B:ApoA1 did not differ between the groups. The ratio of total cholesterol:LDL decreased in men in the fermented soy group (p < 0.001). Twenty-four-hour urine collection at the end of each treatment period resulted in an increased excretion expressed as a ratio in µmol/d between treatments of 10.93 (CI: 5.07, 23.54) for daidzein; 1.24 (CI: 1.14, 4.43) for genistein; and, 8.48 (CI: 4.28, 16.80) for glycitein, all p < 0.05. The fermented soy powder consumed by participants in this study without implementing other changes in their typical diets, decreased the total and LDL cholesterol, and may serve as a dietary strategy to manage blood lipids. The trial was registered at ClinicalTrials.gov as NCT03429920.

The Connection between Urinary Equol Levels and the Prevalence of Atopic Dermatitis.

BACKGROUND: Soy isoflavones and their metabolites such as equol have been associated with a reduced risk of hormone-sensitive tumors and metabolic syndromes. However, individual soy isoflavones and equol levels in atopic dermatitis remain uninvestigated. OBJECTIVE: The aim of this study is to compare the levels of urinary daidzein, genistein, and equol between atopic dermatitis patients and normal subjects and to examine the correlation between equol concentration and the severity of clinical symptoms. METHODS: A cross-sectional study was conducted at Akita University Hospital and Aso Iizuka Hospital in Japan. Fifty patients with confirmed atopic dermatitis diagnosis and 67 healthy controls were recruited. Daidzein, genistein, and equol in urine were measured by using a high-performance liquid chromatography-mass spectrometry system. RESULTS: Urinary equol levels were significantly lower in the atopic dermatitis patients than in the healthy controls (p = 0.002). The difference was particularly noticeable in young people (6-19 years, p < 0.001). No correlations were found between urinary equol levels and the severity of clinical symptoms and laboratory data in the atopic dermatitis patients. CONCLUSION: Equol levels in childhood might be involved in the development of atopic dermatitis.

Urinary Isoflavones Levels in Relation to Serum Thyroid Hormone Concentrations in Female and Male Adults in the U.S. General Population.

Isoflavones are phytoestrogens found in plant-based foods and nutritional supplements. Experimental studies show a positive association between isoflavones and hypothyroidism, but epidemiological findings are conflicting. We used multivariable linear regression to examine the association between urinary isoflavone concentrations and serum thyroid hormone concentrations in the National Health and Nutrition Examination Survey (2007-2010). In this study, we found that Daidzein and O-DMA associations with free T4 were stronger among women: a 10-fold increase in daidzein was associated with a 3.2% (95% CI: 1.9%, 4.5%) increase in women and a 0.6% (95% CI: -1.7%, 0.6%) decrease in men and a 10-fold increase in O-DMA was related to a 2.0% (95% CI: 1.1%, 2.9%) increase in women and a 0.3% (95% CI: -1.2%, 0.5%) decrease in men. In this study, selected urinary isoflavone concentrations were associated with serum thyroid hormone concentration in a sex-dependent fashion.

Drinking Refined Deep-Sea Water Improves the Gut Ecosystem with Beneficial Effects on Intestinal Health in Humans: A Randomized Double-Blind Controlled Trial.

World health trends are focusing on a balanced food and beverage intake for healthy life. Refined deep-sea water (RDSW), obtained from deep-sea water collected offshore in Muroto (Japan), is mineral-rich drinking water. We previously reported that drinking RDSW improves human gut health. Here, we analyzed the effect of drinking RDSW on the gut ecosystem to understand this effect. This was a randomized double-blind controlled trial. Ninety-eight healthy adults were divided into two groups: RDSW or mineral water (control). The participants consumed 1 L of either water type daily for 12 weeks. A self-administered questionnaire and stool and urine samples were collected through the intervention. The following were determined: fecal biomarkers of secretory immunoglobulin A (sIgA), five putrefactive products, and nine short-chain-fatty-acids (SCFAs) as the primary outcomes; and three urinary isoflavones and the questionnaire as secondary outcomes. In post-intervention in the RDSW group, we found increased concentrations of five SCFAs and decreased concentrations of phenol and sIgA (p < 0.05). The multiple logistic analysis demonstrated that RDSW significantly affected two biomarkers (acetic and 3-methylbutanoic acids) of the five SCFAs mentioned above (p < 0.05). Similarly, the concentrations of urinary isoflavones tended to increase in post-intervention in the RDSW group. Constipation was significantly alleviated in the RDSW group (94%) compared with the control group (60%). Drinking RDSW improves the intestinal environment, increasing fecal SCFAs and urinary isoflavones, which leads to broad beneficial effects in human.

Associations of Urinary Phytoestrogen Concentrations with Sleep Disorders and Sleep Duration among Adults.

Current evidence on the relationship of phytoestrogens with sleep is limited and contradictory. In particular, studies on individual phytoestrogens and sleep have not been reported. Thus, this study aimed to appraise the associations of individual phytoestrogens with sleep disorders and sleep duration. This cross-sectional study comprising 4830 adults utilized data from the National Health and Nutrition Examination Survey 2005-2010. Phytoestrogens were tested in urine specimens. Sleep disorders and sleep duration were based on a self-reported doctor's diagnosis and usual sleep duration. The main analyses utilized logistic and multinomial logistic regression models and a restricted cubic spline. In the fully adjusted model, compared with tertile 1 (lowest), the odds ratios (95% confidence intervals (CIs)) of sleep disorders for the highest tertile of urinary concentrations of enterolactone, enterodiol, and O-desmethylangolensin were 0.64 (0.41-1.00), 1.54 (1.07-2.21), and 1.89 (1.26-2.85), respectively. Linear inverse, approximatively linear positive, and inverted L-shaped concentration-response relationships were found between enterolactone, enterodiol, and O-desmethylangolensin and sleep disorders, respectively. Compared with normal sleep (7-8 h/night), the relative risk ratio (RRR) (95% CI) of very short sleep for enterolactone was 0.56 (0.36-0.86), and the RRR (95% CI) of long sleep risk for genistein was 0.62 (0.39-0.99). Furthermore, negative associations of genistein with sleep disorders and enterolactone with long sleep risk, as well as positive associations of enterodiol with both long and very short sleep, were observed in the stratified analysis by age or gender. Finally, a notable finding was that urinary O-desmethylangolensin concentration was positively related to sleep disorders in both females aged 40-59 years and non-Hispanic Whites but inversely associated with sleep disorders in both females aged 60 years or over and other Hispanics. Our findings suggested that enterolactone and genistein might be beneficial for preventing sleep disorders or non-normal sleep duration among adults, and enterodiol might be adverse toward this goal. However, the association of O-desmethylangolensin with sleep disorders might be discrepant in different races and females of different ages.

Metabolic tracking of isoflavones in soybean products and biosamples from healthy adults after fermented soybean consumption.

Fermentation may enhance the nutritional properties of foods by increasing metabolite bioactivity or bioavailability. This study explored the effect of fermentation on isoflavone bioavailability and metabolism. Isoflavone metabolites were tracked in foods and biospecimens of healthy adults after fermented soybean (FS) or non-fermented soybean (NFS) consumption in a randomized, controlled, crossover intervention study. The change in soybean isoflavones caused by fermentation resulted in faster absorption and higher bioavailability after consumption of FS. Although the urinary level of total isoflavone metabolites was similar after the consumption of the two diets, urinary genistein 7-O-sulfate was derived as a discriminant metabolite for the FS diet by partial least squares discriminant analysis. This study suggests that an isoflavone conjugate profile might be a more appropriate marker than total isoflavone levels for discriminating between the consumption of FS and NFS diets.

Reduction of inflammation in chronic pancreatitis using a soy bread intervention: A feasibility study.

INTRODUCTION: Chronic pancreatitis is a chronic inflammatory disease, which progresses to fibrosis. Currently there are no interventions to delay or stop the progression to irreversible organ damage. In this study, we assessed the tolerability and feasibility of administering soy bread to reduce circulating inflammatory mediators. METHODS: Subjects with chronic pancreatitis diagnosed using the American Pancreatic Association diagnostic guidelines were enrolled. During the dose escalation (DE) phase, subjects received one week of soy bread based using a 3 + 3 dose-escalation design, which was then followed by a maximally tolerated dose (MTD) phase with four weeks of intervention. Dose-limiting toxicities (DLTs) were monitored. Plasma cytokine levels were measured using a Meso Scale Discovery multiplex assay kit. Isoflavonoid excretion in 24-h urine collection was used to measure soy bread compliance. RESULTS: Nine subjects completed the DE phase, and one subject completed the MTD phase without any DLTs at a maximum dosage of three slices (99 mg of isoflavones) per day. Reported compliance to soy bread intervention was 98%, and this was confirmed with urinary isoflavones and their metabolites detected in all subjects. There was a significant decline in the TNF-α level during the DE phase (2.667 vs 2.382 pg/mL, p = 0.039); other levels were similar. CONCLUSIONS: In this feasibility study, there was excellent compliance with a short-term intervention using soy bread in chronic pancreatitis. Reduction was seen in at least one pro-inflammatory cytokine with short-term intervention. Larger cohorts and longer interventions with soy are warranted to assess the efficacy of reducing pro-inflammatory mediators of disease.

Simultaneous determination of formononetin, biochanin A and their active metabolites in human breast milk, saliva and urine using salting-out assisted liquid-liquid extraction and ultra high performance liquid chromatography-electrospray ionization tandem mass spectrum.

Isoflavonoid phytoestrogens, referred as "dietary estrogens" are widely distributed in the plant kingdom. Formononetin, biochanin A and their active metabolites daidzein and genistein are known to be the most potent among other isoflavonoid phytoestrogens. Thus there is a growing need to determine accurately their concentration in different biological fluids. In the present work, a sensitive analytical method was developed for the quantitative determination of these compounds in human breast milk, saliva and urine. The glycoside conjugates of these compounds were enzymatically hydrolysis prior to salting-out assisted liquid-liquid extraction. Quantitative analysis was done by ultra high performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry. The obtained results showed high correlation coefficients (r2 > 0.998) for the linear range established for formononetine, biochanin A, daidzein and genistein. The limits of detection (LODs) and low limits of quantitation (LLOQs) were in the ranges of 0.05-1.0 ng/mL and 1.0-4.0 ng/mL for all analytes in human biological fluids, respectively. The average recoveries ranged from 83.29% to 115.24% for the analytes with relative standard deviation (n = 5) values from 1.84% to 9.75% in samples. Both intra-day and inter-day precisions and accuracy were found to be within 12.53% and ± 12.92% respectively. Under different conditions of stability, the concentrations for four isoflavonoid phytoestrogens deviated within ±12.87% of norminal values. The developed method was successfully validated and applied to human breast milk, saliva and urine. The average concentrations of daidzein and genistein found in breast milk, saliva and urine samples ranged from 0 to 104.2 µg/kg, 18.17 to 786.0 µg/kg, 0 to 10974 µg/kg, respectively. Their presence in breast milk samples shows exposure of breast-fed baby to isoflavones. It also allows for the rapid screening of human biological fluids when testing for formononetin, biochanin A, daidzein and genistein production status in human.

Effects of a low-fat dietary regimen enriched with soy in children affected with heterozygous familial hypercholesterolemia.

INTRODUCTION: Familial hypercholesterolemia (FH) is an inheritable, autosomal dominant disorder leading to pathologically increased levels of low-density-lipoprotein cholesterol (LDL-C). Dietary treatment remains an important tool in the management of affected children even after the decision for the initiation of pharmacotherapy is made. However, little evidence is available regarding the optimal dietary regimen for the treatment of children affected with FH. METHODS: We present results from a randomized controlled trial in paediatric patients affected with heterozygous FH, assessing the effect of a soy-enriched fat modified diet (soy group) compared to fat modified diet (Control group) alone on LDL-C over a period of 13 weeks. Furthermore, we monitored isoflavone levels in plasma and urine as markers of adherence to the dietary treatments. RESULTS: LDL-C decrease was statistically significantly greater in the soy group compared to the control group at week 7 (Control group 176.3 ± 27.8 mg/dl, soy group 154.7 ± 29.2 mg/dl, p = 0.038), and showed a trend towards significant at week 13 (Control group 179.9 ± 41.8 mg/dl, soy group 155.0 ± 30.2 mg/dl, p = 0.089). Relative LDL-C decrease correlated significantly with the following plasma isoflavone concentrations measured in week 7: daidzein (p < 0.004, r = 0.576) and genistein (p < 0.017, r = 0.490). CONCLUSIONS: We provide evidence from a small randomized-controlled trial for the effectiveness and safety of a dietary treatment with soy in paediatric patients affected with heterozygous FH. The decrease in LDL-C was highly correlated with isoflavone levels, further highlighting a direct effect of soy ingestion. This study was registered under ClinicalTrials.gov Identifier No. NCT03563547.

Urine Metabonomic Analysis of Interventions Effect of Soy Isoflavones on Rats Exposed to Di-(2-ethylhexyl) Phthalate.

OBJECTIVE: Di-(2-ethylhexyl) phthalate (DEHP) is a ubiquitous environmental contaminant. As an endocrine disruptor, it seriously threatens human health and ecological environmental safety. This study examines the impact of intervention with soybean isoflavones (SIF) on DEHP-induced toxicity using a metabonomics approach. METHODS: Rats were randomly divided into control (H), SIF-treated (A, 86 mg/kg body weight), DEHP-treated (B, 68 mg/kg), and SIF plus DEHP-treated (D) groups. Rats were given SIF and DEHP daily through diet and gavage, respectively. After 30 d of treatment, rat urine was tested using UPLC/MS with multivariate analysis. Metabolic changes were also evaluated using biochemical assays. RESULTS: Metabolomics analyses revealed that p-cresol glucuronide, methyl hippuric acid, N1-methyl-2-pyridone-5-carboxamide, lysophosphatidycholine [18:2 (9Z, 12Z)] {lysoPC [18:2 (9Z, 12Z)]}, lysoPC (16:0), xanthosine, undecanedioic acid, and N6-acetyl-l-lysine were present at significantly different levels in control and treatment groups. CONCLUSION: SIF supplementation partially protects rats from DEHP-induced metabolic abnormalities by regulating fatty acid metabolism, antioxidant defense system, amino acid metabolism, and is also involved in the protection of mitochondria.

Sensitive and selective detection of puerarin based on the hybrid of reduced graphene oxide and molecularly imprinted polymer.

Puerarin, an important isoflavone, has been widely used for the treatment of angina and hypertension. In this work, we developed a novel electrochemical sensor for the detection of puerarin based on the hybrid of reduced graphene oxide (RGO) and molecularly imprinted polymer (MIP). The RGO/MIP sensor functions by target puerarin recognition and electro-oxidization via a two-proton and two-electron process, enabling the detection of puerarin with good selectivity and high sensitivity. The MIP layer was integrated on the surface of RGO by the electro-co-polymerization of o-phenylenediamine (monomer) and puerarin (template), resulting in high surface area, binding capacity, good conductivity and faster mass transfer. The nanostructure of the RGO/MIP hybrid was demonstrated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Experimental conditions involved in the sensor fabrication process were evaluated. Under the optimized condition, a wide linear range (0.02 µM ∼ 40 µM) and a low detection limit (0.006 µM) were achieved. The sensor was applied to detect puerarin in human urine and injection samples, and the result was comparable with that of the gold standard method of high-performance liquid chromatography (HPLC), indicating a promise in the further application to pharmacokinetics or therapeutic drug monitoring.

Urinary equol, but not daidzein and genistein, was inversely associated with the risk of type 2 diabetes in Chinese adults.

PURPOSE: Many studies have examined the association of isoflavone intake with type 2 diabetes (T2D), and produced inconsistent results. Few studies, however, explored the association using objective biomarkers (particular for daidzein metabolite-equol) of isoflavones. We aimed to explore the association of urinary equol, daidzein and genistein concentrations with T2D and examine the mediating roles of high-sensitivity C-reactive protein (hsCRP) and retinol binding protein 4 (RBP4). METHODS: This prospective study included 2818 subjects. Urinary concentrations of equol, daidzein and genistein were measured by high-performance liquid chromatography-tandem mass spectrometry. The associations between urinary isoflavones and T2D incidence were evaluated by cox proportional hazards model. RESULTS: After adjustment for covariates, urinary equol except daidzein and genistein was inversely associated with T2D incidence. In comparison with the first tertile, multivariable adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs) for T2D incidence in the second and third tertile of equol concentration were 0.52 (0.37, 0.73) and 0.72 (0.53, 0.97), respectively. In stratified analyses by sex, the HR (95% CI) of men in the second vs. first tertile of equol was 0.29 (0.14, 0.58). Equivalent estimation in women was 0.67 (0.45, 1.01). Neither women nor men in the third tertile showed significant difference of T2D incidence compared with the first tertile. In path analyses, there was no evidence of mediating effects of hsCRP and RBP4 on the "equol-T2D" relationship. CONCLUSIONS: Urinary equol was favorably associated with a decreased T2D incidence in Chinese adults. The equol-T2D relationship might not be mediated by hsCRP and RBP4. TRIAL REGISTRATION: This study has been registered at http://www.clinicaltrials.gov as NCT03179657.

Daidzein and genistein have differential effects in decreasing whole body bone mineral density but had no effect on hip and spine density in premenopausal women: A 2-year randomized, double-blind, placebo-controlled study.

Soy isoflavones are potentially beneficial phytoestrogens, but their tissue-selective effects in women are poorly understood. We tested the hypothesis that soy isoflavones affect bone mineral density (BMD), which may be influenced by individual differences in isoflavone metabolism and serum calcium levels. Ninety-nine healthy premenopausal women were randomized to isoflavones (136.6 mg aglycone equivalence) and 98 to placebo for 5 days per week for up to 2 years. BMD, serum calcium, and urinary excretion of daidzein and genistein were measured before and during treatment. In 129 adherent subjects, we found that isoflavone exposure, determined by urinary excretion levels, but not by dose assignment, interacted with serum calcium in affecting whole body BMD, but not hip and spine BMD. The regression coefficient was -0.042 for genistein excretion (GE) and 0.091 for the interaction between GE and serum calcium (all P < .05). Daidzein excretion had similar but marginal effect. Genistein significantly decreased whole body BMD only at low normal serum calcium levels but increased whole body BMD at higher serum calcium levels. Comparing maximum to minimum GE, mean changes in whole body BMD were +0.033 and -0.113 g/cm2 at serum calcium levels of 10 and 8.15 mg/dL, respectively. These associations were not evident by intention-to-treat analysis, which could not model for inter-individual differences in isoflavone metabolism. In summary, soy isoflavones decrease whole body BMD only when serum calcium is low. Isoflavones are dietary substances that may influence calcium homeostasis by releasing calcium from bone while sparing the common fracture risk sites hip and spine.

Prediagnostic Level of Dietary and Urinary Isoflavonoids in Relation to Risk of Liver Cancer in Shanghai, China.

BACKGROUND: No epidemiologic studies have directly assessed the association between dietary and urinary isoflavonoids and risk of liver cancer in humans. METHODS: A nested case-control study, including 217 incident cases of liver cancer and 427 individually matched control subjects, was conducted in Shanghai, China. Dietary isoflavonoid intakes were assessed through a validated food-frequency questionnaire and the Chinese Food Composition Tables. Urinary excretion levels of four major isoflavonoids were measured by the reversed-phase high-performance liquid chromatography. ORs and 95% confidence intervals (CI) were derived using conditional logistic regression models. RESULTS: The adjusted ORs (95% CIs) for liver cancer across increasing quartiles of urinary genistein levels were 1.00 (reference), 0.55 (95% CI, 0.22-1.36), 0.57 (95% CI, 0.23-1.43), and 0.19 (95% CI, 0.06-0.59) (P trend = 0.008) in women and 1.00 (reference), 1.22 (0.52-2.86), 1.17(0.47-2.90), and 1.23 (0.55-2.76) in men, respectively. These associations were consistent by limiting the cases to primary malignant neoplasm of liver or malignant neoplasms of the intrahepatic bile ducts, or among participants without self-reported liver disease or cirrhosis at the baseline survey. No associations were found between dietary isoflavonoids and liver cancer risk. CONCLUSIONS: Our study suggests for the first time that urinary excretion of genistein may be associated with reduced risk of liver cancer in women. IMPACT: In this nested case-control study in China, we found that urinary excretion of genistein was associated with lower risk of liver cancer in women, and not in men.

An investigation on the metabolic pathways of synthetic isoflavones by gas chromatography coupled to high accuracy mass spectrometry.

RATIONALE: Isoflavones are a group of flavonoids that may be of interest in sport doping because they can be used by athletes in the recovery periods after the administration of anabolic steroids, with the aim of increasing the natural production of luteinizing hormone (LH) and, consequently, the biosynthesis of endogenous androgens. METHODS: The in vivo metabolism of methoxyisoflavone (5-methyl-7-methoxyisoflavone) and ipriflavone (7-isopropoxyisoflavone), respectively present in a dietary supplement and in a pharmaceutical preparation, was investigated. The study was carried out by the analysis of urinary samples collected from male Caucasian subjects before, during and after the oral administration of methoxyisoflavone or ipriflavone. After enzymatic hydrolysis and liquid-liquid extraction, all urinary samples were analyzed by gas chromatography/quadrupole time-of-flight (qTOF MS system/qTOF) electron ionization mass spectrometry (EI-MS). RESULTS: Eight metabolites of methoxyisoflavone and six metabolites of ipriflavone were isolated. The corresponding accurate mass spectra are specific for isoflavone structures and revealed also a retro-Diels-Alder fragmentation. CONCLUSIONS: When excreted in large amounts, the urinary metabolites of methoxyisoflavone and ipriflavone can be traced to potential confounding factors in doping analysis. As methoxyisoflavone and ipriflavone have been shown to inhibit the enzyme aromatase, thus interfering with the normal metabolic pathways of testosterone, the detection of their intake, by screening for the presence of their main metabolites in urine, might be helpful in routine doping control analysis.