Diets high in saturated fat increase intestinal inflammation associated with IBD via alterations in the microbiota

Abstract

Clinical evidence suggests the chronic inflammation seen in inflammatory bowel diseases (IBD) results from a combination of environmental/microbial factors on a background of genetic susceptibility. This study evaluates the environmental factor of dietary fat composition on the incidence of IBD via alterations in gut microbiota. Male C57bl/6j mice (6 w/o) were fed a high saturated fat (SF; 47% energy from carbohydrates, 16% energy from protein, 37% energy from fat), high polyunsaturated fat (PF; 47:16:37), or a low fat control diet (C; 70:16:14) for 3 wks (n=10/diet). Cecal contents were collected for microbial pyrosequencing of 16s rDNA and revealed a “bloom” of b.wadsworthia, a cytotoxic proteobacteria, only in the SF diet. Body weight was greater on SF diet than PF and LF despite no significant difference in kcals consumed, suggesting an increased microbial capacity for energy harvest on SF, a contributing factor to local inflammation. Next, male IL‐10−/− mice (4 w/o), a model of spontaneous colitis, were fed LF or SF (n=5/diet) for 12 wks. Only 20% of these mice developed colitis on LF vs. 100% on SF accompanied by a 4‐fold increase in pro‐inflammatory IL‐6 and IL‐12 and a microbial profile like that of the C57bl/6j mice fed SF. These data indicate that SF diets create an environment favorable for the growth of harmful bacteria contributing to incidence to IBD.Supported by the National Institutes of Health R01 and T32Grant Funding Source: National Institutes of Health