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Background Many studies have investigated the effects of soy isoflavones on weight control, but few have focused on the role of equol, a gut-derived metabolite of daidzein with greater bioavailability than other soy isoflavones. Objectives This study examined the association of equol production with obesity and explored the mediating roles of equol-related gut microbiota and microbial carnitine metabolites. Methods This 6.6-y prospective study included 2958 Chinese adults (2011 females and 947 males) aged 60.6 ± 6.0 y (mean ± SD) at baseline. Urinary equol and isoflavones were measured using HPLC–tandem MS. BMI, percentage fat mass (%FM), and serum triglycerides (TGs) were assessed every 3 y. Metagenomics sequencing and assessment of carnitine metabolites in feces were performed in a subsample of 897 participants. Results Urinary equol, but not daidzein and genistein, was independently and inversely associated with the obesity-related indicators of BMI, %FM, and a biomarker (TGs). Equol producers (EPs) had lower odds of adiposity conditions and a reduced risk of 6.6-y obesity progression than non-EPs among total participants. Gut microbial analyses indicated that EPs had higher microbiome species richness (P =  3.42 × 10−5) and significantly different β-diversity of gut microbiota compared with the non-EP group (P  = 0.001), with 20 of 162 species differing significantly. EPs (compared with non-EPs) had higher abundances of Alistipes senegalensis and Coprococcus catus but lower abundances of Ruminococcus gnavus (false discovery rate <0.05). Among the 7 determined fecal acylcarnitine metabolites, palmitoylcarnitine, oleylcarnitine 18:1, and stearylcarnitine were inversely associated with EPs but positively correlated with obesity conditions and progression. Path analyses indicated that the beneficial association between equol and obesity might be mediated by gut microbiota and decreased production of 3 acylcarnitines in feces. Conclusions This study suggests a beneficial association between equol and obesity, mediated by the gut microbiome and acylcarnitines, in adults. This trial was registered at clinicaltrials.gov as NCT03179657. [ABSTRACT FROM AUTHOR]

Most previous studies have examined the associations between carotenoids and anthropometrics with cross-sectional designs. Few studies have investigated the associations between serum carotenoids and fat mass and fat distribution (general vs central type). This study aimed to explore the associations of serum carotenoids with body fat and fat distribution in Chinese adults. Cross-sectional and longitudinal analyses of a prospective, community-based cohort were performed. There were 4,048 participants aged 40 to 75 years recruited in the Guangzhou Nutrition and Health Study from 2008 to 2013. Serum carotenoids were assessed at baseline. Anthropometrics, fat mass (FM), and percentage FM (%FM) over the total body, trunk, limbs, and android and gynoid regions were obtained by dual-energy x-ray absorptiometry for 3,002 participants between 2011 and 2013 and for 2,537 participants after 3.1 years. Cross-sectional and longitudinal analyses were performed to compare the mean differences in adiposity indices among the quartiles of carotenoids. Covariance analyses showed significant inverse associations between serum total carotenoid levels and adiposity indices cross-sectionally (all P trends<0.05). The percentage mean differences in quartile 4 (vs 1) in FM and %FM were much more pronounced in the trunk (–15.4% and –7.74%) and android area (–16.6% and –8.59%) than those in the limbs (–8.31% and –4.51%) and gynoid area (–7.76% and –2.71%) (all P <0.001). Longitudinal results revealed that higher total carotenoids were associated with significantly lower 3-year increases in body mass index (calculated as kg/m2); waist circumference; waist-to-hip ratio; body FM in the limbs and android and gynoid area; and %FM in total body, trunk, and limbs (all P trends<0.05). Regarding individual carotenoids, β-carotene tended to have the most notable beneficial associations with the majority of fat indices, especially for cross-sectional analyses. Serum carotenoid concentrations are inversely associated with body fat, especially in the abdominal region, in Chinese adults. [ABSTRACT FROM AUTHOR]