Equol Production Research Articles

Equol Nonproducing Status as an Independent Risk Factor for Acute Cardioembolic Stroke and Poor Functional Outcome.

Background/Objectives: Equol has protective effects against coronary artery disease and dementia by strongly binding to estrogen receptor beta, whereas the intake of soy isoflavone alone does not always confer such protective effects. Equol production is completely dependent on the existence of equol-producing gut microbiota. The effects of equol-producing status on the cerebrovascular diseases remain unclear. The current study was aimed to investigate the association of equol-producing status with the development of stroke and its neurological prognosis. Methods: Frequencies of equol producers were compared between healthy subjects (HS) registered in the Suita Study and patients with acute stroke admitted to our stroke center from September 2019 to October 2021 in a retrospective cohort study. Results: The proportion of HSs and patients with ischemic stroke who were equol producers did not significantly differ (50/103 [48.5%] vs. 60/140 [42.9%], p = 0.38). However, cardioembolic stroke was significantly associated with low a prevalence of equol producers (adjusted odds ratio [aOR] 0.46, 95% confidence interval [CI] 0.21-0.99, p = 0.05). A higher left atrial volume index was observed in equol nonproducers (46.3 ± 23.8 vs. 36.0 ± 11.6 mL/m2, p = 0.06). The equol nonproducers had a significantly higher prevalence of atrial fibrillation than the equol producers (27.5% vs. 13.3%, p = 0.04). Furthermore, the equol producers exhibited a significantly favorable functional outcome upon discharge (aOR 2.84, 95% CI 1.20-6.75, p = 0.02). Conclusions: Equol is a promising candidate for interventions aiming to reduce the risk of CES and atrial dysfunction, such as atrial fibrillation and improve neurological prognosis after ischemic stroke.

Production of equol, dehydroequol, 5-hydroxy-equol and 5-hydroxy-dehydroequol in soy beverages by the action of dihydrodaidzein reductase in Limosilactobacillus fermentum strains

Equol and 5-hydroxy-equol, and their analogous compounds dehydroequol and 5-hydroxy-dehydroequol, are bioactive isoflavones formed by microbial metabolism. The aims of this work were to elucidate the formation of dehydroequol and 5-hydroxy-dehydroequol, to identify the role of dihydrodaidzein reductase (DHDR) in the production of equol, dehydroequol, 5-hydroxy-equol and 5-hydroxy-dehydroequol and to develop soy beverages enriched in these compounds through engineered lactic acid bacteria. DHDR was responsible for the production of equol and dehydroequol from dihydrodaidzein (DHD), and of 5-hydroxy-equol and 5-hydroxy-dehydroequol from dihydrogenistein (DHG), even in the absence of tetrahydrodaidzein reductase (THDR). The combination of DHDR with dihydrodaidzein racemase (DDRC), and/or THDR, allowed the production of soy beverages enriched in equol (241.34 ± 34.56 μM), dehydroequol (31.23 ± 5.78 μM), 5-hydroxy-equol (125.54 ± 7.90 μM) and 5-hydroxy-dehydroequol (292.34 ± 14.67 μM). Beverages fortified with high concentrations of equol, 5-hydroxy-dehydroequol and 5-hydroxy-equol could provide significant health benefits for consumers.

Effect of Fermented Soy Beverage on Equol Production by Fecal Microbiota.

Soy consumption is associated with health benefits, mainly linked to the ability of the intestinal microbiota to metabolize the glycosylated isoflavones into more bioactive compounds, such as equol. Because Bifidobacterium pseudocatenulatum INIA P815 is able to efficiently deglycosylate daidzin into daidzein, the aim of this work was to confirm the influence of soy beverages fermented by B. pseudocatenulatum INIA P815 for enhancing equol production by fecal microbiota. Firstly, fecal samples from 17 participants were characterized in vitro, and we observed that 35.3% of them were able to produce equol from daidzein. In addition, the kinetics of equol production and degradation by fecal microbiota were evaluated, determining that 30-85% of equol is degraded after 24 h of incubation. Finally, the influence of fermented soy beverage on improving the production of equol by selected equol-producing fecal samples and by the equol-producing strain Slackia isoflavoniconvertens was analyzed through a colonic model. Fermented soy beverage enhanced the equol production from S. isoflavoniconvertens as well as the fecal samples whose microbiota showed high rates of equol degradation. The results obtained confirm that the fermentation of soy beverages with selected bacterial strains improves the functional properties of these beverages in terms of isoflavone metabolism and equol production.

The relationship between equol production status and normal tension glaucoma

PurposeEquol is metabolized by intestinal bacteria from soy isoflavones and is chemically similar to estrogen. Dietary habits, such as consumption of soy products, influence equol production. A relationship between glaucoma and estrogen has been identified; here, we investigated the relationship between equol production status and glaucoma in Japan.MethodsWe recruited 68 normal-tension glaucoma (NTG) patients (male to female ratio 26:42, average age 63.0 ± 7.6 years) and 31 controls (male to female ratio 13:18, average age 66.0 ± 6.3 years) from our hospital. All women included were postmenopausal. Urinary equol concentration was quantified with the ELISA method. MD was calculated based on the Humphrey visual field. The association between MD and equol was analyzed with Spearman’s rank correlation coefficient. The Mann–Whitney U test was used to compare the equol-producing (> 1 μM) and non-producing (< 1 μM) subjects. We also investigated the association between equol and glaucoma with a logistic regression analysis.ResultsThere was a significant association between equol and MD (r = 0.36, P < 0.01) in the NTG patients. Glaucoma, represented by MD, was significantly milder in the equol-producing subjects than the non-equol producing subjects (P = 0.03). A multivariate analysis revealed the independent contributions of equol, cpRNFLT, and IOP to MD (P = 0.03, P = 0.04, and P < 0.01, respectively).ConclusionOur results suggest that equol, acting through estrogen receptor-mediated neuroprotective effects, might be involved in suppressing the progression of NTG. This result also adds to evidence that glaucoma may be influenced by lifestyle.

A Gnotobiotic Mouse Model with Divergent Equol-Producing Phenotypes: Potential for Determining Microbial-Driven Health Impacts of Soy Isoflavone Daidzein.

The implications of soy consumption on human health have been a subject of debate, largely due to the mixed evidence regarding its benefits and potential risks. The variability in responses to soy has been partly attributed to differences in the metabolism of soy isoflavones, compounds with structural similarities to estrogen. Approximately one-third of humans possess gut bacteria capable of converting soy isoflavone daidzein into equol, a metabolite produced exclusively by gut microbiota with significant estrogenic potency. In contrast, lab-raised rodents are efficient equol producers, except for those raised germ-free. This discrepancy raises concerns about the applicability of traditional rodent models to humans. Herein, we designed a gnotobiotic mouse model to differentiate between equol producers and non-producers by introducing synthetic bacterial communities with and without the equol-producing capacity into female and male germ-free mice. These gnotobiotic mice display equol-producing phenotypes consistent with the capacity of the gut microbiota received. Our findings confirm the model's efficacy in mimicking human equol production capacity, offering a promising tool for future studies to explore the relationship between endogenous equol production and health outcomes like cardiometabolic health and fertility. This approach aims to refine dietary guidelines by considering individual microbiome differences.

Comparison of blood and urine concentrations of equol by LC‒MS/MS method and factors associated with equol production in 466 Japanese men and women.

Equol is produced from daidzein by the action of gut bacteria on soy isoflavones. However, not all people can produce equol, and metabolism differs even among the producers. We aimed to examine the equol producer status in both men and women, and investigate the relationships among the serum and urinary isoflavones as well as to other biomedical parameters. In this study, we measured the equol and daidzein concentrations from the blood and urine of 292 men and 174 women aged between 22 and 88 years by liquid chromatography-tandem mass spectrometry (LC‒MS/MS). We then analysed the cut-off value for equol producers in both sexes, the relationship of serum and urinary equol concentrations, and other parameters, such as sex, age, endocrine function, glucose metabolism, lipid metabolism, and renal function with regards to equol-producing ability, among the different age groups. Equol producers were defined as those whose log ratio of urinary equol and daidzein concentration or log (equol/daidzein) was -1.42 or higher. Among 466 participants, 195 were equol producers (42%). The proportion of equol producers was larger in women. The cut-off value for equol producers was consistent in both sexes. Positive relationships were noted between serum and urinary equol levels in equol producers of both sexes; however, such a relationship was not detected in nonproducers. Lipid and uric acid abnormalities were more common with non equol producers in both men and women. Prostate specific antigen (PSA) levels in men were significantly lower in equol producers, especially in those in their 40 s. This study suggests a relationship between equol-producing ability and reduced risk of prostate disease as well as positive effects of equol on blood lipids and uric acid levels. However, lack of dietary information and disperse age groups were major drawbacks in generalizing the results of this study.

Indole-3-acetic acid alleviates DSS-induced colitis by promoting the production of R-equol from Bifidobacterium pseudolongum

ABSTRACT Background Inflammatory bowel disease (IBD) is characterized by immune-mediated, chronic inflammation of the intestinal tract. The occurrence of IBD is driven by the complex interactions of multiple factors. The objective of this study was to evaluate the therapeutic effects of IAA in colitis. Method C57/BL6 mice were administered 2.5% DSS in drinking water to induce colitis. IAA, Bifidobacterium pseudolongum, and R-equol were administered by oral gavage and fed a regular diet. The Disease Activity Index was used to evaluate disease activity. The degree of colitis was evaluated using histological morphology, RNA, and inflammation marker proteins. CD45+ CD4+ FOXP3+ Treg and CD45+ CD4+ IL17A+ Th17 cells were detected by flow cytometry. Analysis of the gut microbiome in fecal content was performed using 16S rRNA gene sequencing. Gut microbiome metabolites were analyzed using Untargeted Metabolomics. Result In our study, we found IAA alleviates DSS-induced colitis in mice by altering the gut microbiome. The abundance of Bifidobacterium pseudolongum significantly increased in the IAA treatment group. Bifidobacterium pseudolongum ATCC25526 alleviates DSS-induced colitis by increasing the ratio of Foxp3+T cells in colon tissue. R-equol alleviates DSS-induced colitis by increasing Foxp3+T cells, which may be the mechanism by which ATCC25526 alleviates DSS-induced colitis in mice. Conclusion Our study demonstrates that IAA, an indole derivative, alleviates DSS-induced colitis by promoting the production of Equol from Bifidobacterium pseudolongum, which provides new insights into gut homeostasis regulated by indole metabolites other than the classic AHR pathway.

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 aimsNo 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. MethodsThis 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. ResultsProportions 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 PSA11PSA: prostate specific antigen. 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 LDL22LDL: low density lipoprotein-hypercholesterolemia by 50 %, and female EQP identified by this definition seemed to have lower risk of high hs-CRP,33CRP: C-reactive protein 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. ConclusionsMore 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.

Deciphering the Crucial Roles of the Quorum-Sensing Transcription Factor SdiA in NADPH Metabolism and (S)-Equol Production in Escherichia coli Nissle 1917.

The active metabolite (S)-equol, derived from daidzein by gut microbiota, exhibits superior antioxidative activity compared with its precursor and plays a vital role in human health. As only 25% to 50% of individuals can naturally produce equol when supplied with isoflavone, we engineered probiotic E. coli Nissle 1917 (EcN) to convert dietary isoflavones into (S)-equol, thus offering a strategy to mimic the gut phenotype of natural (S)-equol producers. However, co-fermentation of EcN-eq with fecal bacteria revealed that gut microbial metabolites decreased NADPH levels, hindering (S)-equol production. Transcriptome analysis showed that the quorum-sensing (QS) transcription factor SdiA negatively regulates NADPH levels and (S)-equol biosynthesis in EcN-eq. Screening AHLs showed that SdiA binding to C10-HSL negatively regulates the pentose phosphate pathway, reducing intracellular NADPH levels in EcN-eq. Molecular docking and dynamics simulations investigated the structural disparities in complexes formed by C10-HSL with SdiA from EcN or E. coli K12. Substituting sdiA_EcN in EcN-eq with sdiA_K12 increased the intracellular NADPH/NADP+ ratio, enhancing (S)-equol production by 47%. These findings elucidate the impact of AHL-QS in the gut microbiota on EcN NADPH metabolism, offering insights for developing (S)-equol-producing EcN probiotics tailored to the gut environment.

Abstract WP263: Associations of Equol-Producing Status With Cardioembolic Stroke in Japanese Patients With Stroke

Introduction: Equol, a metabolite of a soy isoflavone daidzein transformed by the gut microbiota, is associated with the amelioration of cardiovascular diseases and cognitive impairment. Approximately 50% of Asians and 30% of Westerners may be equol producers depending on the presence of equol-producing gut microbiota. It is still unknown whether equol-producing status is associated with development of stroke and its prognosis. Methods: In this single-center, retrospective study, we investigated the serum concentration of equol in 200 patients with stroke hospitalized in the National Cerebral and Cardiovascular Center (NCVC) from September 2019 to October 2021, and 103 healthy subjects registered in the Suita Study, a population-based cohort study at NCVC from November 2016 to September 2018. The concentration of equol was measured using liquid chromatography-mass spectrometry. Results: Eighty-five patients with stroke (43.5%) and 50 healthy subjects (48.5%) were equol producers ( p =0.32). However, patients with cardioembolic stroke (CES) had a significantly lower frequency of the equol producers (28.9%) compared to healthy subjects ( p =0.04), as well as patients with other stroke subtypes (48.0%) ( p =0.04). The prevalence of atrial fibrillation was significantly lower in equol producers than that in non-producers (26.3% vs. 47.3%, p =0.04) among patients with ischemic stroke. Additionally, equol-producing status was an independent predictor for a favorable outcome (modified Rankin scale 0-2) at discharge for ischemic stroke in a multivariable logistic regression analysis (odds ratio 2.75, 95% confidential interval 1.05-7.27, p =0.04). Discussion: CES, atrial fibrillation, and clinical outcome may be influenced by equol-producing status. These findings could provide new insights into the racial difference in the prevalence of CES between Asians and Westerners.

Preparation of a Lactobacillus rhamnosus ATCC 7469 microencapsulated-lactulose synbiotic and its effect on equol production.

Equol is a highly active product of soy isoflavones produced by specific bacteria in the human or animal colon. However, equol production is influenced by differences in the gut flora carried by the body. Our previous research has shown that a synbiotic preparation comprising the probiotic Lactobacillus rhamnosus ATCC 7469 and the prebiotic lactulose can enhance equol production by modulating the intestinal flora. Nevertheless, the harsh environment of the gastrointestinal tract limits this capability by diminishing the number of probiotics reaching the colon. Microencapsulation of probiotics is an effective strategy to enhance their viability. In this study, probiotic gel microspheres (SA-S-CS) were prepared using an extrusion method, with sodium alginate (SA) and chitosan (CS) serving as the encapsulating materials. Scanning electron microscopy (SEM) was employed to observe the surface morphology and the internal distribution of bacteria within the microcapsules. The structural characteristics of the microcapsules were investigated using Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Furthermore, the thermal stability, storage stability, probiotic viability post-simulated gastrointestinal fluid treatment, and colon release rate were examined. Finally, the impact of probiotic microencapsulation on promoting equol production by the synbiotic preparation was assessed. The results indicated that the microcapsules exhibited a spherical structure with bacteria evenly distributed on the inner surface. Studies on thermal and storage stability showed that the number of viable cells in the probiotic microcapsule group significantly increased compared to the free probiotic group. Gastrointestinal tolerance studies revealed that after in vitro simulated gastrointestinal digestion, the amount of viable cells in the microcapsules was 7 log10 CFU g-1, demonstrating good gastrointestinal tolerance. Moreover, after incubation in simulated colonic fluid for 150 min, the release rate of probiotics reached 93.13%. This suggests that chitosan-coated sodium alginate microcapsules can shield Lactobacillus rhamnosus ATCC 7469 from the gastrointestinal environment, offering a novel model for synbiotic preparation to enhance equol production.

Advances in equol production: Sustainable strategies for unlocking soy isoflavone benefits

Daidzein is an abundant polyphenol present in soy and other legumes. It accumulates mostly in seed and seed pod during the plant development in response to biotic and abiotic stress. Due to the high consumption of soy and soy derivative food, daidzein is one of the most abundant polyphenols in human and cattle diets. Similar to other phytochemicals, daidzein is not absorbed or metabolized by human cells, but transformed by enzymatic cascades of the gut microbiome. The product of daidzein “fermentation” is equol and related molecules. Equol [7-hydroxy-3-(4'-hydroxyphenyl)-chroman] is considered the most active metabolite of all soybean isoflavones, presenting a high level of antioxidant and estrogenic activity. This bioactive molecule presents estrogen-like activity by specifically binding to 5α-dihydrotestosterone and inhibiting its binding to the androgen receptor. Biotransformation of daidzein into equol requires enzymes that are not widespread along all microbiome taxa but restricted to a relatively small number of enzymes from the family Eggerthellaceae (phylum Actinomycetota, formerly Actinobacteria), strict anaerobes that inhabit the colon of humans and anoxic areas of the intestinal tract of other mammals. The isolation and characterization of equol-producing bacteria from the human gut resulted in the identification of bacterial species that, due to their metabolic capacity, were named Adlercreutzia equolifaciens, Slackia equolifaciens, Slackia isoflavoniconvertens, among others. Combining genomic and biochemical analysis, the puzzle of diadzein biotransformation was decoded. It includes an initial step catalyzed by β-glucosidases, enzymes that are commonly found in the intestinal tract and deglycosylate the natural form of daidzein in the plant, followed by the action of bacterial enzymes daidzein reductase, dihydrodaidzein reductase, tetrahydrodaidzein reductase, and dihydrodaidzein racemase. Undoubtedly, improving daidzein production from soy products or enhancing daidzein biotransformation by the human gut microbiome is of notorious biotechnological and biomedical interest. In addition, the chemistry catalyzed by the equol biosynthetic enzymes is of interest in the green chemistry field. However, the extreme oxygen sensitivity of the microbes and enzymes that participate in these pathways still impose a challenge for translating the knowledge obtained with recombinant enzymes and model organisms into the food industry. In this manuscript we review the process of equol biosynthesis and the effort in synthetic biology for production of equol into industrial or biomedical setups.

Association between lignan polyphenol bioavailability and enterotypes of isoflavone metabolism: A cross-sectional analysis.

Lignan polyphenols derived from plants are metabolized by bacteria in the gut to mammalian lignans, such as enterolactone (ENL) and enterodiol (END). Mammalian lignan intake has been reported to be associated with obesity and low blood glucose levels. However, the factors that are responsible for individual differences in the metabolic capacity for ENL and END are not well understood. In the present study, the effects of enterotypes of isoflavone metabolism, equol producers (EQP) and O-desmethylangolensin producers (O-DMAP), on lignan metabolism were examined. EQP was defined by urinary daidzein (DAI) and equol concentrations as log(equol/DAI) ≥ -1.42. O-DMAP was defined by urinary DAI and O-DMA concentrations as O-DMA/DAI > 0.018. Isoflavone and lignan concentrations in urine samples from 440 Japanese women were measured by gas chromatography-mass spectrometry. Metabolic enterotypes were determined from the urinary equol and O-DMA concentrations. Urinary END and ENL concentrations were compared in four groups, combinations of EQP (+/-) and O-DMAP (+/-). The urinary lignan concentration was significantly higher in the O-DMAP/EQP group (ENL: P<0.001, END: P<0.001), and this association remained significant after adjusting for several background variables (END: β = 0.138, P = 0.00607 for EQP and β = 0.147, P = 0.00328 for O-DMAP; ENL: β = 0.312, P<0.001 for EQP and β = 0.210, P<0.001 for O-DMAP). The ENL/END ratio was also highest in the O-DMAP/EQP group, indicating that equol and O-DMA metabolizing gut bacteria may be involved in lignan metabolism. In conclusion, urinary lignan concentrations were significantly higher in groups containing either EQP or O-DMAP than in the non-EQP/non-O-DMAP group. The variables and participants in this study were limited, which the possibility of confounding by other variables cannot be ruled out. However, there are no established determinants of lignan metabolism to date. Further research is needed to determine what factors should be considered, and to examine in different settings to confirm the external validity.

Microbiomes in Post–Digital Rectal Exam Urine Samples are Linked to Prostate Cancer Risk

Abstract Purpose: Bacterial species including Cutibacterium acnes (C. acnes) have been associated with different inflammatory and neoplastic conditions in prostate cancer (PCa) tissue samples, but their clinical impact is unknown. Using next-generation sequencing (NGS)–based clinical reports, we investigated the differential abundance and incidence of microbiomes in post–digital rectal exam (DRE) urine samples from patients with PCa and a matched control group at low risk of PCa. Materials and Methods: A total of 200 post-DRE urine samples were analyzed, 100 from patients with histopathologically confirmed PCa and 100 from men at very low risk of PCa with PSA &lt;1.5 ng/mL as controls. Bacterial and fungal communities were characterized by NGS of 16S and internal transcribed spacer (ITS) loci, respectively, with species' relative abundances provided on physicians' clinical reports. The differential abundance and incidence of species between cancer and control groups were evaluated. Results: Microbes were reported in 39% and 56% of PCa and control group samples, respectively. C. acnes had a significantly higher relative abundance in patients with PCa vs controls (P &lt; .05), and C. acnes incidence rates were also nominally higher in patients with PCa as compared with controls (12.82% and 7.27%, respectively). By contrast, Finegoldia magna (F. magna) had a significantly higher relative abundance (P &lt; .05) and incidence rate (P &lt; .05) in controls as compared with patients with PCa. Conclusions: C. acnes was among the most prevalent bacterial species in PCa urine samples. F. magna identified in the low-risk group is responsible for production of equol, a soy metabolite associated with lowering risk of PCa, suggesting a role in prostate cancer chemoprevention.

Unveiling metabotype clustering in resveratrol, daidzein, and ellagic acid metabolism: Prevalence, associated gut microbiomes, and their distinctive microbial networks

The gut microbiota (GM) produces different polyphenol-derived metabolites, yielding high interindividual variability and hampering consistent health effects. GM metabotypes associated with ellagic acid (urolithin metabotypes A (UMA), B (UMB), and 0 (UM0)), resveratrol (lunularin -producers (LP) and non-producers (LNP)), and daidzein (equol-producers (EP) and non-producers (ENP)) are known. However, individual polyphenol-related metabotypes do not occur individually. In contrast, different combinations coexist (i.e., metabotype clusters, MCs). We report here for the first time these MCs, their distribution, and their associated GM in adult humans (n = 127) after consuming for 7 days a nutraceutical (pomegranate, Polygonum cuspidatum, and red clover extracts) containing ellagitannins + ellagic acid, resveratrol, and isoflavones. Urine metabolites (UHPLC-QTOF-MS) and fecal microbiota (16S rRNA sequencing) were analyzed. Ten MCs were identified: LP + UMB + ENP (22.7%), LP + UMA + ENP (21.3%), LP + UMA + EP (16.7%), LP + UMB + EP (16%), LNP + UMA + ENP (11.3%), LNP + UMB + ENP (5.3%), LNP + UMA + EP (3.3%), LNP + UMB + EP (2%), LNP + UM0 + EP (0.7%), and LNP + UM0 + ENP (0.7%). Sex, BMI, and age did not affect the distribution of metabotypes or MCs. Multivariate analysis (MaAslin2) revealed genera differentially present in individual metabotypes and MCs. Network analysis (MENA) showed the taxa acting as module hubs and connectors. Compositional and functional profiling, alpha and beta diversities, topological network features, and GM modulation by the nutraceutical differed depending on whether the entire cohort or each MC was considered. The nutraceutical did not change the composition of LP + UMA + EP (the most robust GM with the most associated functions) but increased its network connectors. This pioneering approach, joining GM’s compositional, functional, and network features in polyphenol metabolism, paves the way for identifying personalized GM-targeted strategies to improve polyphenol health benefits.

Gut microbiome association with brain imaging markers, APOE genotype, calcium and vegetable intakes, and obesity in healthy aging adults.

Advanced age is a significant factor in changes to brain physiology and cognitive functions. Recent research has highlighted the critical role of the gut microbiome in modulating brain functions during aging, which can be influenced by various factors such as apolipoprotein E (APOE) genetic variance, body mass index (BMI), diabetes, and dietary intake. However, the associations between the gut microbiome and these factors, as well as brain structural, vascular, and metabolic imaging markers, have not been well explored. We recruited 30 community dwelling older adults between age 55-85 in Kentucky. We collected the medical history from the electronic health record as well as the Dietary Screener Questionnaire. We performed APOE genotyping with an oral swab, gut microbiome analysis using metagenomics sequencing, and brain structural, vascular, and metabolic imaging using MRI. Individuals with APOE e2 and APOE e4 genotypes had distinct microbiota composition, and higher level of pro-inflammatory microbiota were associated higher BMI and diabetes. In contrast, calcium- and vegetable-rich diets were associated with microbiota that produced short chain fatty acids leading to an anti-inflammatory state. We also found that important gut microbial butyrate producers were correlated with the volume of the thalamus and corpus callosum, which are regions of the brain responsible for relaying and processing information. Additionally, putative proinflammatory species were negatively correlated with GABA production, an inhibitory neurotransmitter. Furthermore, we observed that the relative abundance of bacteria from the family Eggerthellaceae, equol producers, was correlated with white matter integrity in tracts connecting the brain regions related to language, memory, and learning. These findings highlight the importance of gut microbiome association with brain health in aging population and could have important implications aimed at optimizing healthy brain aging through precision prebiotic, probiotic or dietary interventions.

Association between equol and non-alcoholic fatty liver disease in Japanese women in their 50s and 60s.

Equol is a metabolite of soy isoflavone and has estrogenic activity. The incidence of non-alcoholic fatty liver disease (NAFLD) increases after menopause in women, which is thought to result in a decrease in estrogen. This study aimed to evaluate the association between equol and NAFLD. We evaluated 1185 women aged 50-69years who underwent health check-ups at four health centers in Fukushima, Japan. Equol producers were defined by a urinary equol concentration of 1.0μM or more. In addition to comparison between equol producers and non-producers, the association between equol and NAFLD was estimated using logistic regression analysis adjusting for fast walking and eating habits. Of the 1185 participants, 345 (29.1%) women were equol producers. The proportions of women who had NAFLD (34.8% vs 45.2%) were significantly lower in the equol-producing group than in the non-producing group. Multivariable logistic regression analysis showed that equol production was significantly associated with NAFLD (odds ratio=0.66, 95% confidence interval: 0.51-0.86). Equol production was significantly associated with NAFLD in women in their 50s and 60s.

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

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. The participants included 147 patients with typediabetes 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). 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). Our study findings showed that postmenopausal women had a low proportion of equol producers with diabetes and dyslipidemia.

Evaluation of the Relationship Between Equol Production and the Risk of Locomotive Syndrome in Very Elderly Women

This study aimed to evaluate whether equol production status has an impact on the risk of locomotive syndrome in very elderly (≥85 years old) women. In this retrospective observational study, 116 very elderly women were recruited from those who lived in nursing homes for the elderly from June 2018 to November 2019. Equol production status was determined by measuring spot urine levels of equol, and risks of locomotive syndrome were evaluated by vulnerable fracture history and loco-check, a simple questionnaire comprising seven questions that can describe locomotive syndrome. Equol production (≥1 μmol/L in a spot urine sample) was found in 46 women (39.6%). Loss of equol production contributes to some lococheck items, which correlate with weakness of lower limb muscle strength (P &lt; 0.05). In this study population, 57 women (49.1%) had previous vulnerable fractures. However, equol production status was not significantly related to the vulnerable fracture in this study population (P = 0.159). Equol production might contribute to the induction of locomotive syndrome, at least in part. However, equol deficiency as a mechanism of locomotive syndrome induction might not be the primary cause of a previous vulnerable fracture in very elderly women who live in nursing homes.

Assessment of short-read shotgun sequencing and microbiome analysis of faecal samples to discriminate between equol producers and non-producers.

Among the isoflavones and isoflavone-derived metabolites, equol, which in the human gut is synthesised from daidzein by minority bacterial populations, shows the strongest estrogenic and antioxidant activity. The beneficial effects on human health of isoflavone consumption might be partially or indeed totally attributable to this equol. Although some of the bacterial strains involved in its formation have been identified, the interplay between the composition and functionality of the gut microbiota and equol producer phenotype has hardly been studied. In this study, after shotgun metagenomic sequencing, different pipelines for the taxonomic and functional annotation of sequencing data were used in the search for similarities and differences in the faecal metagenome of equol-producing (n=3) and non-producing (n=2) women, with special focus on equol-producing taxa and their equol-associated genes. The taxonomic profiles of the samples differed significantly depending on the analytical method followed, although the microbial diversity detected by each tool was very similar at the phylum, genus and species levels. Equol-producing taxa were detected in both equol producers and non-producers, but no correlation between the abundance of equol-producing taxa and the equol producing/non-producing phenotype was found. Indeed, functional metagenomic analysis was unable to identify the genes involved in equol production, even in samples from equol producers. By aligning equol operons with the collected metagenomics data, a small number of reads mapping to equol-associated sequences were recognised in samples from both equol producers and equol non-producers, but only two reads mapping onto equol reductase-encoding genes in a sample from an equol producer. In conclusion, the taxonomic analysis of metagenomic data might not be suitable for detecting and quantifying equol-producing microbes in human faeces. Functional analysis of the data might provide an alternative. However, to detect the genetic makeup of the minority gut populations, more extensive sequencing than that achieved in the present study might be required.