Equol Status Research Articles

Equol-producing status affects exercise training-induced improvement in arterial compliance in postmenopausal women.

Central arterial compliance decreases drastically after menopause. Regular intake of soy isoflavone and aerobic exercise increase arterial compliance. The equol is a metabolite of isoflavone daidzein by gut microbiome. We determined whether the equol-producing status affects aerobic exercise-induced improvement in carotid arterial compliance. Forty-three postmenopausal women were assigned to two intervention groups: 1) exercise and isoflavone (Ex+Iso, n = 27 females) or 2) isoflavone interventions (Iso; n = 16 females). Participants of the Ex+Iso intervention group completed an 8-wk aerobic exercise training, and all participants were administered with oral isoflavone supplements during the interventions. The equol-producing status (equol producers or nonproducers) was determined from urine equol concentrations after a soy challenge. In the Ex+Iso intervention group, carotid arterial compliance increased in the equol producers (0.084 ± 0.030→0.117 ± 0.035 mm2/mmHg), but not in the nonproducers (0.089 ± 0.028→0.097 ± 0.026 mm2/mmHg) after the intervention (interaction effect; P < 0.05). The magnitude of increases in carotid arterial compliance was significantly greater in the equol producers than in the non-equol producers (P < 0.05). In the isoflavone intervention group, there were no changes in any parameters after the intervention irrespective of the equol status. These results suggest that equol-producing status is obligatory to aerobic exercise training-induced improvements in central arterial compliance in postmenopausal women.NEW & NOTEWORTHY Isoflavone intake and aerobic exercise increase central artery compliance. Equol, a metabolite of isoflavone daidzein by gut microbiome, has beneficial effects on vascular function. We demonstrated for the first time that the interaction of aerobic exercise and equol production status plays an essential role in improvements in central artery compliance in postmenopausal women. More specifically, the equol-producing status was obligatory to exercise training-induced improvements in central arterial compliance in postmenopausal women.

Tracking isoflavones in whole soy flour, soy muffins and the plasma of hypercholesterolaemic adults

Information on changes in soy isoflavones during processing is needed to better understand the relationship between isoforms, food matrix, bioavailability and health. The abundance and transformation of isoflavones were tracked in soy flour, a baked soy muffin and plasma of hypercholesterolaemic adults (n = 142) who consumed muffins daily for 6 weeks. Isoflavones were identified and quantified in soy flour and muffins by HPLC-UV and in plasma by LC-MS/MS. Equol status was determined and used to assess the relationship between plasma isoflavones and dietary factors. Baking soy flour altered the relative proportion of isoflavone isoforms by promoting a conversion of malonyl- to β-glucosides in soy muffins (P < 0.001). Daily soy consumption resulted in >3-fold increase in plasma isoflavones with a doubling of dose (P < 0.001). Dietary factors did not correlate with plasma isoflavones. These findings may be used to guide the development of soy-based functional foods.

Individual difference in faecal and urine equol excretion and their correlation with intestinal microbiota in large white sows

Equol is an end metabolite of daidzein produced by the intestinal microbiota, exhibiting stronger antioxidant and estrogenic activities. It has been proposed that the beneficial effects of soybean/phytoestrogens may be dependent on the intestinal equol-producing ability, i.e. the equol hypothesis. The ‘equol hypothesis’ has been well applied to human clinical studies. However, the information of equol-producing ability in sows is quite limited. In this study, the individual differences and correlation between equol excretion and intestinal microbiota in large white sows were assayed. The results showed faecal equol levels of 0.14–17.85 μg/g (coefficient of variation: 61.22%) and urinary equol levels of 0.53–8.19 μg/mL (coefficient of variation: 54.72%). The levels of equol and daidzein correlated positively in both urine and faeces (P &lt; 0.05). The levels of daidzein and ratio of equol : daidzein in both faeces and urine were significantly higher than equol status (P &lt; 0.01). Cluster analysis of denatured gradient gel electrophoresis patterns showed that faecal samples with similar equol concentrations had similar microbial composition. The Shannon diversity and bands number in gel was significant negatively correlative with faecal equol status (P &lt; 0.001). The population of total bacteria, Firmicutes and Bacteroidetes correlated negatively with faecal equol production (P &lt; 0.05). Positive correlations were found between urinary equol production and the population of bacteroidetes and methanogen-producing bacteria (P &lt; 0.05), demonstrating for the first time the relationship between equol excretions and gut interspecies H2 transfer in sows.

Equol status and changes in fecal microbiota in menopausal women receiving long-term treatment for menopause symptoms with a soy-isoflavone concentrate.

The knowledge regarding the intestinal microbial types involved in isoflavone bioavailability and metabolism is still limited. The present work reports the influence of a treatment with isoflavones for 6 months on the fecal bacterial communities of 16 menopausal women, as determined by culturing and culture-independent microbial techniques. Changes in fecal communities were analyzed with respect to the women’s equol-producing phenotype. Compared to baseline, at 1 and 3 months the counts for all microbial populations in the feces of equol-producing women had increased strongly. In contrast, among the non-producers, the counts for all microbial populations at 1 month were similar to those at baseline, and decreased significantly by 3 and 6 months. Following isoflavone intake, major bands in the denaturing gradient gel electrophoresis (DGGE) profiles appeared and disappeared, suggesting important changes in majority populations. In some women, increases were seen in the intensity of specific DGGE bands corresponding to microorganisms known to be involved in the metabolism of dietary phytoestrogens (Lactonifactor longoviformis, Faecalibacterium prausnitzii, Bifidobacterium sp., Ruminococcus sp.). Real-Time quantitative PCR revealed that the Clostridium leptum and C. coccoides populations increased in equol producers, while those of bifidobacteria and enterobacteria decreased, and vice versa in the non-producers. Finally, the Atopobium population increased in both groups, but especially in the non-producers at three months. As the main findings of this study, (i) variations in the microbial communities over the 6-month period of isoflavone supplementation were large; (ii) no changes in the fecal microbial populations that were convincingly treatment-specific were seen; and (iii) the production of equol did not appear to be associated with the presence of, or increase in the population of, any of the majority bacterial types analyzed.

Effect of soy nuts and equol status on blood pressure, lipids and inflammation in postmenopausal women stratified by metabolic syndrome status

ObjectiveSoy has been associated with lower risk of cardiovascular disease in Asian countries which consume daily soy. Our study examined whether production of equol, an estrogen metabolite, affected the ability of soy nuts to improve cardiovascular risk factors. Materials/MethodsSixty postmenopausal women participated in a randomized, controlled, crossover trial of a Therapeutic Lifestyle Changes (TLC) diet alone and a TLC diet in which 0.5 cup of soy nuts (25 g of soy protein and 101 mg of aglycone isoflavones) replaced 25 g of nonsoy protein daily. Each diet was followed for 8 weeks at the end of which blood pressure (BP), lipid levels, adhesion molecules and inflammatory markers were measured. ResultsWomen with MetS had significantly higher baseline body mass index (BMI), BP, triglycerides (TG), and soluble intercellular adhesion molecule (sICAM) than women without MetS. In women with MetS on the soy diet, significant reductions in diastolic BP (7.7%; P=0.02), TG (22.9%; P=0.02), C-reactive protein (CRP) (21.4%; P=0.01) and sICAM (7.3%; P=0.03) were noted among equol producers compared to levels on the TLC diet. No significant changes were noted in equol nonproducers. Similarly, in women without MetS, only equol producers had significant reductions in diastolic BP (3.3%, P=0.02) and CRP (30%, P=0.04). In contrast to women with MetS, TG and sICAM levels were not affected in women without MetS, a finding possibly related to lower baseline levels. ConclusionsCardiovascular risk reduction with soy nuts is not uniform and may be greater among producers of equol.

Inter- and intra-individual variation in urinary excretion of daidzein and equol in female Japanese

Objective: To evaluate the representativeness of single measurement of urinary soy-isoflavone concentrations for the assessment of long-term intake levels.Methods: Five urine samples taken from 14 Japanese female subjects over 2–3 months were measured for daidzein and equol by gas chromatography-mass spectrometry (GC-MS).Results: Geometric mean daidzein and equol concentrations of 14 subjects were 582 and 2.66 μg/g creatinine, respectively. Intra-class correlation coefficients for daidzein and equol were 0.355 (95% CI: 0.130–0.649) and 0.741 (0.551–0.891), respectively.Conclusion: Single measurement of urinary equol is effective for the assessment of long-term equol status of Japanese subject while that of daidzein is not.

Daidzein Supplementation Decreases Serum Triglyceride and Uric Acid Concentrations in Hypercholesterolemic Adults with the Effect on Triglycerides Being Greater in Those with the GA Compared with the GG Genotype of ESR-β RsaI1–3

Daidzein (one of the major isoflavones) can be metabolized to equol in certain individuals. The effects of isoflavones alone and equol status on lipid profiles are still controversial. To evaluate the 6-mo effects of daidzein on cardiovascular risk factors in hypercholesterolemic individuals and the interactions of these effects with equol status and estrogen receptor (ESR) genotypes, we conducted a randomized, double-blind, placebo-controlled trial consisting of 210 hypercholesterolemic adults (40–65 y old). The participants were randomly assigned (177 completed) to consume placebo, 40 mg daidzein (DAI40), or 80 mg daidzein (DAI80) daily for 6 mo. Daidzein decreased serum triglycerides (TGs) by 0.15 ± 0.62 mmol/L (mean ± SD) and 0.24 ± 0.61 mmol/L and decreased serum uric acid by 23 ± 47 μmol/L and 29 ± 44 μmol/L in the DAI40 and DAI80 groups, respectively. These reductions in the DAI40 and DAI80 groups were greater than those in the placebo group (P < 0.05). Other blood lipids, glucose, insulin, or glycated hemoglobin did not significantly change after daidzein treatment. No dose-dependent effects of daidzein were found. The reduction of TGs was influenced by the ESR genotype, with a greater effect observed in participants with the GA genotype compared with those with the GG genotype of ESR-β RsaI. These effects were not influenced by equol status. Six-month supplementation of daidzein significantly decreased TGs and uric acid. ESR-β RsaI genotype, not equol status, influenced daidzein’s effects on TGs. Daidzein consumption may be effective to improve cardiovascular risk factors, especially in adults with the GA genotype of ESR-β RsaI. This trial was registered at the Chinese clinical trial registry as ChiCTR-TRC-10001048.

Effects of natural S‐equol supplements on overweight or obesity and metabolic syndrome in the Japanese, based on sex and equol status

Epidemiologic studies indicate that soy intake has an important role in the prevention of age-related health problems. Daidzein, the principal isoflavone contained in soy, is converted to S-equol by the intestinal bacteria. Not all individuals, however, can produce S-equol, which is considered the most biologically active metabolite. We studied the effects of a natural S-equol supplement on metabolic parameters associated with overweight or obesity and metabolic syndrome. The study was a randomized, double-blinded, placebo-controlled, crossover design with no washout period. All subjects were considered overweight or obese if they had a body mass index ≥ 25 kg/m(2) . Placebo or natural S-equol tablets containing 10 mg S-equol were orally ingested each day for 12 weeks. A total of 54 Japanese overweight or obese outpatients were enrolled. The equol phenotype was determined, and various metabolic parameters, including cardio-ankle vascular index (CAVI), were measured. Equol non-producers comprised 67.9% of the overweight or obese subjects. The ratio of equol non-producers in this overweight or obese subject group was higher than the previously reported ratio of equol non-producers (approximately 50%) in the general population. Compared with the placebo group, intervention with natural S-equol led to a significant decrease in HbA1c, serum low-density lipoprotein cholesterol (LDL-C) levels and CAVI score. Furthermore, the effect was more prominent in the subgroup of female equol non-producers. The ratio of equol non-producers in overweight or obese populations might be higher than generally reported. Natural S-equol might have a role in glycaemic control and in the prevention of cardiovascular disease by its effects to lower LDL-C levels and CAVI scores in overweight or obese individuals.

EFFECT OF SOY NUTS ON INFLAMMATION, ENDOTHELIAL FUNCTION, GLUCOSE, AND INSULIN IN ADULTS WITH METABOLIC SYNDROME

Metabolic Syndrome (MetS), a clustering of risk factors for CVD and T2DM, has been increasing in prevalence. Inflammation and endothelial dysfunction represent early phases in the pathophysiology of these chronic diseases. A paucity of studies have examined soy consumption with MetS. This randomized controlled crossover trial investigated a commercially available soy snack (soy nuts) in menopausal women and older men with MetS. The hypothesis was that the soy snack would significantly attenuate inflammatory biomarkers, improve endothelial function, and achieve better glucose and insulin control. 9 adults with MetS were assigned in random order to the snack interventions for 4 weeks each: soy nuts and a macronutrient‐matched control (cookies baked in‐house). Outcome measurements included RH‐PAT, blood samples, anthropometrics, and food records. Preliminary baseline characteristics include 3M and 6F, 55.3±4.9 years, BMI 31.5±3.4 kg/m2, and 3.7±0.7 of 5 MetS criteria. Current results show no significant differences between snack interventions, time, and order. Equol status, NO, ET‐1, IL‐10, and food records will also be analyzed. Collectively, the enrollment goal is 18 and statistical analysis at that time will better reveal effects of soy nuts on inflammation, endothelial function, glucose, and insulin in adults with MetS.Grant Funding Source : UC Davis Departmental Funds and Henry A. Jastro Research Award

Equol status and blood lipid profile in hyperlipidemia after consumption of diets containing soy foods

Recent analyses have challenged the effectiveness of soy foods as part of a cardiovascular risk reduction diet. The objective of the study was to show whether equol status determines the effectiveness of soy foods to lower LDL cholesterol and to raise HDL cholesterol. Eighty-five hypercholesterolemic men and postmenopausal women (42 men, 43 women) participated in 1 of 3 studies that represented a range of soy interventions and that followed the same general protocol at a Canadian university hospital research center. Soy foods were provided for 1 mo at doses of 30-52 g/d for the 3 studies as follows: 1) soy foods with either high-normal (73 mg/d) or low (10 mg/d) isoflavones, 2) soy foods with or without a prebiotic to enhance colonic fermentation (10 g polyfructans/d), or 3) soy foods with a low-carbohydrate diet (26% carbohydrate). Studies 1 and 2 were randomized controlled crossover trials, and study 3 was a parallel study. The separation of the group into equol producers (n = 30) and nonproducers (n = 55) showed similar reductions from baseline in LDL cholesterol (-9.3 ± 2.5% and -11.1 ± 1.6%, respectively; P = 0.834), with preservation of HDL cholesterol and apolipoprotein A-I only in equol producers compared with reductions in nonproducers (HDL cholesterol: +0.9 ± 2.7% compared with -4.3 ± 1.1%, P = 0.006; apolipoprotein A-I: -1.0 ± 1.1% compared with -4.7 ± 1.0%; P = 0.011). The amount of urinary equol excreted did not relate to the changes in blood lipids. Soy foods reduced serum LDL cholesterol equally in both equol producers and nonproducers. However, in equol producers, ~35% of our study population, soy consumption had the added cardiovascular benefit of maintaining higher HDL-cholesterol concentrations than those seen in equol nonproducers. This trial was registered at clinicaltrials.gov as NCT00877825 (study 1), NCT00516594 (study 2), and NCT00256516 (study 3).

Equol production changes over time in pre-menopausal women

Equol (EQ) is a metabolite produced by gut bacteria through the chemical reduction of the soya isoflavone daidzein (DE), but only by 30-60% of the population. EQ is believed to provide benefits derived from soya intake and its production is widely viewed as a relatively stable phenomenon. In a randomised, cross-over intervention with soya foods, seventy-nine pre-menopausal women were challenged with a high-soya and a low-soya diet each for 6 months, separated by a 1-month washout period. Overnight urine was collected at three time points during each diet period and analysed for DE and EQ by liquid chromatography tandem MS. Remaining an EQ producer (EP) or non-producer (NP) or changing towards an EP or NP was assessed using an EQ:DE ratio of ≥0·018 combined with a DE threshold of ≥2 nmol/mg creatinine as a cut-off point. We observed 19 and 24% EP during the low-soya and high-soya diet periods, respectively, and found that 6-11% of our subjects changed EQ status 'within' each study period (on an average of 1·2 times), while 16% changed 'between' the two diet periods. The present finding challenges the widely held conviction that EQ production within an individual remains stable over time. The precise factors contributing to changes in EQ status, however, remain elusive and warrant further investigation.

Equol production changes over time in postmenopausal women

Equol (EQ) is produced by intestinal bacteria from the soy isoflavone daidzein (DE) in 30%–60% of the population and is believed to provide benefits from soy intake. A robust EQ status definition is lacking, and it is uncertain whether EQ is formed consistently within an individual and ceases upon oral antibiotic treatment.In a randomized, double-blind, placebo-controlled soy intervention trial with 350 postmenopausal women, DE and EQ were analyzed by liquid chromatography/tandem mass spectrometry at baseline and every 6 months over 2.5 years in overnight urine, spot urine and plasma. Equol production changes and status (remaining an EQ producer or nonproducer or changing towards an EQ producer or nonproducer) were assessed.Equol status was determined most dependably by overnight urine applying as cutoff a ratio of EQ/DE≥0.018 with a DE threshold ≥2 nmol/mg creatinine: the soy and placebo groups had approximately 30% consistent EQ producers during the study, but 14% and 35%, respectively, changed EQ status (mean 1.4–1.7 times), while 27% and 17%, respectively, had antibiotic treatment (P<.01 for inverse association). No significant trend in change of EQ production or status was observed when overnight urine was limited to collections closest to before and after antibiotic treatment. Similarly, antibiotic type or class, duration, dose or time between antibiotic treatment and overnight urine collection showed no consistent influence on EQ production.Equol production can markedly change intraindividually over 2.5 years, and antibiotic treatment impacts it inconsistently. Factors other than antibiotic treatment must be considered as causes for EQ production changes.

Equol, via Dietary Sources or Intestinal Production, May Ameliorate Estrogen Deficiency-Induced Bone Loss1–3

Equol, a product of intestinal metabolism of daidzein, is chemically similar to estrogen (without the lipophilic moiety) and has higher estrogen receptor-β binding affinity than its parent precursor. In 2004, a long-term, randomized controlled trial that characterized postmenopausal women by their equol-producing status showed stronger advantages to lumbar spine bone mineral density (BMD) in equol- compared with nonequol-producers. Subsequent studies have related equol status of participants to change in bone turnover markers or BMD in response to soy isoflavone interventions. To our knowledge, we are the first to prescreen women for equol-producing status prior to initiating an intervention. In menopausal Western women, equol status did not affect the modest, but significant, reduction in bone resorption achieved with a soy isoflavone intervention. J. Nutr. 140: 1377S–1379S, 2010.

Equol Status Modifies the Association of Soy Intake and Mammographic Density in a Sample of Postmenopausal Women

Only 30% to 50% of people produce the daidzein-metabolite equol after eating soy. We conducted a cross-sectional study of the associations between equol status, intake of soy foods, and mammographic density in a sample of postmenopausal women recruited at a radiology clinic near Buffalo, New York. Participants were 48 to 82 years old, had no history of cancer or breast reduction/augmentation, and no recent use of antibiotics or hormones. Percent density was measured by computer-assisted analysis of digitized images of craniocaudal films. Equol status was assessed using a soy-challenge protocol and usual soy intake by questionnaire. General linear models were used to assess independent and joint effects of equol status and intake of soy on multivariate adjusted percent density (covariates included age, body mass index, parity, age at first birth, and ever use of combined hormone therapy). Of 325 enrolled, 232 (71%) participants completed study assessments and are included in the present analysis. Mean percent density was 34% (+/-18%). Seventy-five (30%) participants were producers of equol. Forty-three (19%) participants reported regularly eating >1 soy food or supplement/wk. There were no significant independent associations of equol status or soy intake with percent density, but the interaction between these factors was significant (P < 0.01). Among equol producers, those with weekly soy intake had lower percent density (30.7% in weekly consumers of soy versus 38.9% in others; P = 0.08); among nonproducers, weekly soy intake was associated with higher percent density (37.5% in weekly soy consumers versus 30.7% in others; P = 0.03). Results suggest that equol producers and nonproducers may experience different effects of dietary soy on breast tissue.

Possible role of equol status in the effects of isoflavone on bone and fat mass in postmenopausal Japanese women

Equol is more biologically active than its precursor daidzein, which is the principal isoflavone found in soybean. There are interindividual differences in the ability to produce equol; these may lead to differences in the effects of isoflavone intervention on human health. This study aimed to investigate whether the effects of soy isoflavones on bone and fat mass are related to an individual's equol status. We performed a 1-year double-blind, randomized trial to compare the effects of isoflavone (75 mg of isoflavone conjugates/day) with those of placebo on bone mineral density, fat mass, and serum isoflavone concentrations in early postmenopausal Japanese women who were classified based on their equol-producer phenotype. After 1 year, the isoflavone intervention significantly increased the serum equol concentration in the equol producers but not in the nonproducers. In the isoflavone group, the annualized changes in the bone mineral density of the total hip and intertrochanteric regions were -0.46% and -0.04%, respectively, in the equol producers and -2.28% and -2.61%, respectively, in the nonproducers; these values were significantly different (P<0.05 for both the regions). Significant differences were observed between the equol producers and nonproducers in the isoflavone group with regard to the annualized changes in the fat mass. No significant difference in the annualized changes in bone mineral density and fat mass was observed between the equol producers and nonproducers in the placebo group. Our data suggest that the preventive effects of isoflavones on bone loss and fat accumulation in early postmenopausal women depend on an individual's equol-producing capacity.

Isolated isoflavones do not affect the circulating insulin-like growth factor system in men at increased colorectal cancer risk.

Epidemiological studies show that increased insulin-like growth factor (IGF)-I concentrations are related to increased colorectal cancer risk. A reduced colorectal cancer risk has been associated with isoflavones, which might affect the IGF-system because of their weak estrogenic activity. We conducted a randomized, placebo-controlled, double-blind crossover study to investigate the effect of an 8-wk isolated isoflavone supplementation (84 mg/d) on serum concentrations of total IGF-I, free IGF-I, total IGF-II, IGF binding protein (BP)-1, IGFBP-2, and IGFBP-3. Additionally, we investigated whether IGF-system component differences were related to concentrations of the more potent estrogenic isoflavone metabolite, equol. Our study population consisted of 37 men with a family history of colorectal cancer or a personal history of colorectal adenomas. Isoflavone supplementation did not significantly affect serum total IGF-I concentrations (relative difference between serum total IGF-I concentrations after isoflavone supplementation and after placebo: -1.3%, 95% CI -8.6 to 6.0%). Neither free IGF-I, nor total IGF-II, IGFBP-1, IGFBP-2, or IGFBP-3 concentrations were significantly altered. Interestingly, the change in serum IGF-I concentrations after isoflavone supplementation was negatively associated with serum equol concentrations (r=-0.49, P=0.002). In conclusion, isolated isoflavones did not affect the circulating IGF-system in a male high-risk population for colorectal cancer. However, to our knowledge, this is the first study that suggests isoflavones might have an IGF-I lowering effect in equol producers only. This underlines the importance of taking into account equol status in future isoflavone intervention studies.

Cooperative effects of isoflavones and exercise on bone and lipid metabolism in postmenopausal Japanese women: a randomized placebo-controlled trial

Cooperative effects of isoflavones and exercise on bone and lipid metabolism have been exhibited in estrogen-deficient animals; however, results from clinical trials have not been published. In this study, we determined the effects of isoflavone intake and walking and their interaction on bone and lipid metabolism in postmenopausal women over 24 weeks. The bioavailability and metabolism of isoflavones (daidzein in particular) were also examined to clarify the mechanism of their bone-protective effects in humans. One hundred twenty-eight subjects were randomly assigned to 4 groups: placebo; placebo combined with walking (3 times per week); isoflavone intake (75 mg of isoflavones conjugates per day); and isoflavone combined with walking. The subjects were classified by equol status (producers or nonproducers) as identified using production of equol from daidzein in fecal culture. Bone mineral density (BMD), body composition, and serum concentrations of isoflavones were assessed. Serum high-density lipoprotein cholesterol concentration significantly increased (6.1%, P = .03), and fat mass in the whole body significantly decreased (−4.3%, P = .0003) from the baseline in the combined intervention group. There were no significant differences in BMD between baseline and postintervention in any of the treatment groups. However, the percent changes in BMD in equol producers were −0.53% and +0.13% in the sub–whole body and total hip, respectively. This was significantly different compared with −1.35 and −1.77 for the sub–whole body and total hip, respectively, in nonproducers in the isoflavone group ( P = .049 and .040, respectively). The mean serum equol concentration was significantly higher in equol producers than in nonproducers in the isoflavone groups, but not in the placebo group. The combination of isoflavones and exercise exhibited favorable effects on serum lipid and body composition of postmenopausal women. The findings of this study suggest that the preventive effects of isoflavones on bone loss depend on the individual's intestinal flora for equol production.