Monotonous diets protect against acute colitis in mice: epidemiologic and therapeutic implications

Abstract

Objectives: Multiple characteristics of industrialization have been proposed to contribute to the global emergence of inflammatory bowel diseases (IBDs: Crohn disease and ulcerative colitis). Major changes in eating habits during the last decades and the effectiveness of exclusive enteral nutrition in the treatment of Crohn disease indicate the etiologic importance of dietary intake in IBDs. A uniform characteristic of nutrition in developing countries (where the incidence of IBD is low) and exclusive enteral nutrition is their consistent nature for prolonged periods; however, the potentially beneficial effect of dietary monotony in respect to mammalian intestinal inflammation has not been examined.

Methods: The association between alternating (2 different complete chows) and persistent regular diets, and dextran sulfate sodium colitis susceptibility in C57BL/6J mice was studied. Colonic mucosal microbiota changes were investigated by high-throughput pyrosequencing of the 16S rRNA gene.

Results: The severity of colitis increased upon dietary alternation compared with consistent control feeding. The microbiota of the alternating nutritional group clustered discretely from both control groups.

Conclusions: Our findings highlight that monotonous dietary intake may decrease mammalian vulnerability against colitis in association with microbiota separation. The epidemiologic and therapeutic implications of our results are also discussed.

Figure 1

The percentage of total body weight changes during DSS challenge. The animals lost weight similarly up to day 8 of the experiment, but the control (persistent diets) groups started to gain weight by day 9 while the switching group did not. ● regular chow: R; ■NIH-31 diet; NIH-31; ▲switching diet group:SW (#p<0.05 R vs. SW)

Figure 2

Histological severity of colitis in the experimental groups. Colitis severity was significantly higher in the alternating (SW) dietary group. ● regular chow: R; ■NIH-31 diet: NIH-31; ▲switching diet group: SW. p values represent two tailed non-paired T test.

Figure 3

Microbiota diversity in the different groups of the study. There was a trend for decreased diversity in the alternating (switching diet) diet group compared to consistent control chow feeding. p values represent two tailed non-paired T test.

Figure 4

Principal component analysis (PCA) of the colonic mucosal bacterial communities by 16S rRNA analysis. Unweighted Unifrac analysis. The alteration of control chows induced a unique microbiota composition separating from both consistent feeding groups. ● regular chow; ■NIH-31 diet; ▲switching diet group

Figure 5

Correlation between agricultural import and IBD prevalence in Middle-East Europe (Hungary). Between 2001 and 2006, the agricultural import increased in Hungary, with a parallel increase in the prevalence of both ulcerative colitis (UC) and Crohn disease (CD). See Discussion for further details.