Food Additive Guar Gum Aggravates Colonic Inflammation in Experimental Models of Inflammatory Bowel Disease

Abstract Objectives Guar gum, a soluble fiber, is commonly used as a thickener, stabilizer, and source of fiber in processed foods. The food industry has been encouraged to fortify foods with refined guar gum due to its numerous beneficial effects on the human gut and metabolic health. However, we have limited knowledge on whether processed guar gum holds the same physiological effects as its naturally occurring counterpart. In this study, we examined the impact of refined guar gum on intestinal inflammation. Methods We employed three different experimental models of inflammatory bowel disease (IBD)—(1) immune hyperactivity [IL-10 receptor (IL-10R) neutralization], (2) epithelial injury [dextran sulfate sodium (DSS)], and 3) infection [Citrobacter rodentium (CR)]- mediated inflammation—to elucidate the effect of refined guar gum on IBD comprehensively. The colitis development was examined by serological, histological, and immunological parameters. Results Wild-type (WT, C57BL/6) mice receiving guar gum (7.5% w/w) containing diet (GuD) along with α-IL-10R displayed severe colonic inflammation—as characterized by an enlarged spleen, thickening of the colon, and elevated systemic [serum amyloid A (SAA), lipocalin 2 (Lcn2) and keratinocyte-derived chemokine (KC)] and colonic [Lcn2 and interleukin (IL)-1β] markers of inflammation—when compared to mice fed control (cellulose) diet. Histological examination of colonic sections displayed distorted and elongated crypt structure and reduced goblet cells. Inline, GuD-fed mice maintained on DSS (1.4% w/v) for seven days exhibited relatively worsened colitis compared to the control diet-fed group. Specifically, GuD-fed mice showed a more abrupt loss in body weight, diarrhea, rectal bleeding, shortening of colon length, and heightened proinflammatory cytokines, including KC, SAA, and Lcn2. In contrast to what we observed with immune hyperactivation and epithelial injury models, GuD did not exacerbate the CR-induced infectious colitis; however, no sign of protection was evident in the GuD-fed group. Conclusions This study collectively demonstrates that refined guar gum may heighten the intestinal inflammation in patients with IBD. Funding Sources This work is supported by a Career Development Award from the Crohn's & Colitis Foundation.