The associations of the gut microbiome composition and short-chain fatty acid concentrations with body fat distribution in children

Background & aims Previous studies linking the gut microbiome with childhood obesity largely used the body mass index to measure obesity and reached inconsistent findings. Little evidence has linked the gut microbiome to regional body fat deposition. We investigated whether the abundance of specific taxa in the gut microbiota and the concentrations of short-chain fatty acids (SCFAs) were associated with the content and regional deposition of body fat in children. Methods This cross-sectional study involved 236 children aged 6–9 years. The fat mass contents/percentages in the total body and the android, gynoid, and limb regions were determined by dual-energy X-ray absorptiometry, and the android-to-gynoid fat mass ratio and fat-to-lean mass ratios were calculated. Fecal samples were subjected to16S rRNA amplicon sequencing, and the fecal SCFA concentrations were quantified via high-performance liquid chromatography. Results A weighted gene co-expression network analysis identified seven modules of co-expressed operational taxonomic units (OTUs). A total of 57 OTUs from 4 key modules were selected for further analysis. After adjustment of covariates and controlling for the false discovery rate (FDR), a multiple linear regression analysis revealed significant correlations of the abundances of some OTUs with obesity and body fat measures. For instance, the OTUs classified to the species Ruminococcus gnavus and Flavonifractor plautii showed significant negative correlations with the total and regional body fat (β: −0.250 to −0.180, PFDR: 0.041–0.049), whereas OTUs belonging to the genera Blautia and Romboutsia exhibited positive correlations with body fat measures (β: 0.184–0.222, PFDR: 0.041–0.049). The fecal concentrations of acetic, propionic, and butyric acids and total SCFAs were significantly positively correlated with various parameters of body fat distribution (β: 0.160–0.275, PFDR: <0.001–0.042). Conclusion The gut microbiome and SCFAs are significantly associated with obesity and body fat distribution in pediatric population.