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Haskey, Natasha

University of British Columbia

There is growing appreciation that the interaction between diet, the gut microbiota and the immune system contribute to the development and progression of chronic diseases like inflammatory bowel disease (IBD). Various types of dietary fat, independent of total fat content, uniquely influence intestinal inflammation, metabolism, and host-microbe dynamics. The Mediterranean Diet Pattern (MDP) is a health-promoting diet containing approximately 40% total fat. It is unknown if the blend of fats found in the MDP contributes to its beneficial health effects or could benefit patients living with ulcerative colitis (UC). For the experimental study, mice deficient in the mucin 2 gene (muc2-/-) were weaned to 40% fat, isocaloric, and isonitrogenous diets. We sought to clarify the effects of the MD fat blend on colitis by studying dietary fats in isolation from each other and a combination like the blend found in the MDP. We compared the MD fat blend (high monounsaturated fatty acids (MUFA), 2:1 n-6:n-3 polyunsaturated fatty acids (PUFA) and moderate saturated fat acids (SFA)) to diets composed of corn oil (CO, n-6 PUFA), olive oil (OO, high MUFA) or milk fat (MF, SFA) on spontaneous colitis development in Muc2-/- mice. The MD resulted in lower clinical and histopathological scores and induced tolerogenic CD103+CD11b+ dendritic cells, Th22 and IL-17+IL-22+ cells necessary for intestinal barrier repair. The MD was associated with beneficial microbes, and higher cecal acetic acid levels negatively correlated with colitogenic microbes like Akkermansia muciniphila. In contrast, CO showed a higher prevalence of mucin-degraders, including A. muciniphila and Enterobacteriaceae, which have been associated with colitis. For the clinical study, adult patients with quiescent UC were randomized to follow a MDP or Canadian habitual diet (CHD) for 12 weeks. The MDP resulted in reduced disease activity, symptoms, and inflammation-related biomarkers. Food components (fibre, dairy, olive oil and plant-based foods) commonly consumed in a MDP were positively associated with bacteria that produce metabolites related to health (Ruminococcus bromii, Flavonifractor plautii and Lactococcus lactis). Our findings suggest that the MDP could be utilized as adjunctive therapy to manage UC.

Text

2022-06-29

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/81859

Biology

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/