Regulation of Intestinal Inflammation by Dietary Fats

Abstract

With the epidemic of human obesity, dietary fats have increasingly become a focal point of biomedical research. Epidemiological studies indicate that high-fat diets (HFDs), especially those rich in long-chain saturated fatty acids (e.g., Western Diet, National Health Examination survey; NHANES ‘What We Eat in America’ report) have multi-organ pro-inflammatory effects. Experimental studies have confirmed some of these disease associations, and have begun to elaborate mechanisms of disease induction. However, many of the observed effects from epidemiological studies appear to be an over-simplification of the mechanistic complexity that depends on dynamic interactions between the host, the particular fatty acid, and the rather personalized genetics and variability of the gut microbiota. Of interest, experimental studies have shown that certain saturated fats (e.g., lauric and myristic fatty acid-rich coconut oil) could exert the opposite effect; that is, desirable anti-inflammatory and protective mechanisms promoting gut health by unanticipated pathways. Owing to the experimental advantages of laboratory animals for the study of mechanisms under well-controlled dietary settings, we focus this review on the current understanding of how dietary fatty acids impact intestinal biology. We center this discussion on studies from mice and rats, with validation in cell culture systems or human studies. We provide a scoping overview of the most studied diseases mechanisms associated with the induction or prevention of Inflammatory Bowel Disease in rodent models relevant to Crohn’s Disease and Ulcerative Colitis after feeding either high-fat diet (HFD) or feed containing specific fatty acid or other target dietary molecule. Finally, we provide a general outlook on areas that have been largely or scarcely studied, and assess the effects of HFDs on acute and chronic forms of intestinal inflammation.

Fat of the Gut: Epithelial Phospholipids in Inflammatory Bowel Diseases

“…Similarly, the ratio of saturated/unsaturated fatty acids increases favoring arachidonic acid over linoleic and α-linolenic acids during acute stages of CD and UC [ 133 , 134 ]. One of the dietary therapies for IBD is to replace nutritional saturated fatty acid phospholipids with their unsaturated counterparts [ 135 , 136 ].…”

Integrated analysis of dysregulated microRNA and mRNA expression in intestinal epithelial cells following ethanol intoxication and burn injury

“…However, studies also show GLP-2 promotes intestinal barrier integrity by stimulating IEC proliferation, inhibiting apoptosis, and increasing tight junction protein expression 36 , 37 . In addition to the levels of a variety of nutrients, lipid and bile acid metabolism have also been shown to impact gut barrier function and inflammation 38 – 41 . Taken together, these findings suggest that intestinal hypermetabolism after alcohol and burn injury likely plays a major role in gut dysfunction.…”

Reducing Disease Activity of Inflammatory Bowel Disease by Consumption of Plant-Based Foods and Nutrients

“…A major focus in relation to the impact of dietary fats on intestinal inflammatory diseases has been devoted to the difference between high and low dietary fat consumption as recently reviewed ( 56 ). However, as also mentioned in the study, the nutritional composition, particularly the fatty acid composition, has not been reported, except the role of SFAs.…”