Omega‐3 supplementation prevents intestinal inflammation by inhibiting the expansion of an intestinal pathobiont in IL10−/− mice

The human microbiome of Western populations has changed over the past century, brought on by new environmental triggers that often have a negative impact on human health. Previously we showed consumption of a diet high in saturated (anhydrous milkfat‐derived) fat (MF) but not polyunsaturated (safflower oil‐derived)‐fat (PUFA) changes the conditions for microbial assemblage and promotes expansion of a rare, immunogenic, sulfite‐reducing pathobiont, Bilophila wadsworthia. This was associated with a proinflammatory T H 1 immune response and development of colitis in genetically susceptible IL‐10 −/− mice in both specific pathogen free (SPF) and germ‐free environments. The current study examines whether omega‐3 supplementation can attenuate the effect of the MF diet by reducing the bacterial load of B. wadsworthia and subsequent inflammation. SPF IL10 −/− mice were adapted to either a low‐fat (LF), high saturated milk‐fat (MF), fish oil supplemented (FO), or safflower oil supplemented (SO) diets. All three high fat diets were isocaloric with fat comprising 37% total kcal, with the supplemented groups representing 32% MF + 5% FO or SO. After 10wk, 454 pyrosequencing of cecal contents and subsequent principal component analysis revealed colonic bacterial communities of mice on the FO diet were significantly different than those on MF and SO diets. Particularly noticeable was the decrease in abundance of B. wadsworthia in the FO treated mice. This observation was accompanied by reduced levels of IL‐6, IL‐17, IL12p70, and IFNγ, as well as reduced histological colitis scores compared to MF and SO fed mice. Together these data suggest omega‐3 supplementation may decrease risk for inflammatory bowel diseases by suppressing pro‐inflammatatory pathobionts such as B. wadsworthia. Supported by NIH F31. Grant Funding Source : NIH