Diets high in guar gum, a typical food additive and dietary fiber, limited inflammation and delayed the onset of multiple sclerosis (MS) symptoms in mice, in accordance with recent research by members of the University of British Columbia (UBC) Microbiology and Immunology department.
“The rapid increase of autoimmune and inflammatory disorders in industrialized countries in the previous couple of many years indicates dietary decisions are one environmental factor contributing to incidence,” said Dr. Lisa Osborne, senior researcher on the study and an assistant professor with UBC Microbiology and Immunology.
“Dietary fibers are potent modulators of immune responses and might control inflammation in multiple diseases, but they are a very biochemically diverse family. Our study gives us a clearer window into the potential of several sources of fiber in maintaining immune health.”
Dr. Osborne and colleagues exposed groups of mice to a wide range of diets—a control five percent cellulose fiber weight-reduction plan, a weight-reduction plan entirely lacking in dietary fiber, or diets enriched (30%) with fiber in either resistant starch, inulin, pectin, or guar gum. Quar gum was the one fiber type that significantly limited the MS-like symptoms.
Guar gum—guaran—is extracted from guar beans, and is commonly used as an additive to thicken and stabilize food and animal feed, and in industrial applications. India and Pakistan are major growers of the bean.
Guar beans aren’t that common in western diets, and the gum is not used at these high levels as an additive within the west.
Experts have consistently been saying fiber is nice for you—and a wide range of fiber sources is essential to immune health—but there hasn’t been very much critical work into identifying how the body responds to different fiber types. It’s fascinating that this particular source has such an impact.”
Naomi Fettig, First Creator and PhD Student, Department of Microbiology and Immunology at UBC
Within the US and Canada, the typical every day intake of fiber is 15 grams—current recommendations are double that at 30 grams. The really useful values don’t take into consideration any specific fiber type. “Incorporating guar beans could be difficult to attain on the doses we gave to mice,” says Dr. Osborne. “But a guar gum derivative, partially hydrolyzed guar gum, is commercially available as a prebiotic.”
After the gum is broken down by the microbiota of mice, the resulting molecules appeared to cut back the activity and proliferation of a sort of CD4+ T cells, Th1 cells, that play a key part in activating the autoimmune response. It’s that response that results in MS-like symptoms in mice. The results of fiber on Th1 cells remained largely unknown prior to this study, and these findings suggest that the biochemical differences in fiber structures can influence diverse immune pathways.
Dr. Osborne and her lab now wish to explore the potential advantages in humans—including developing a more detailed understanding of the molecular picture, which could help design therapeutics that provide the advantages of such high guar gum diets in a more practical form.
University of British Columbia, Faculty of Science
Fettig, N.M., et al. (2022) Inhibition of Th1 activation and differentiation by dietary guar gum ameliorates experimental autoimmune encephalomyelitis. Cell Reports. doi.org/10.1016/j.celrep.2022.111328.