Research released by scientists from the Institute of Biomedical Sciences (IBMS) at Georgia State University indicates that supplementing the diet with wheat bran shields mice against intestinal inflammation. This discovery sheds light on the rising incidence of Inflammatory Bowel Diseases (IBD) and suggests that consuming whole-grain wheat products might lessen the risk of developing these conditions.*
The study, whose outcomes were detailed in two scientific papers published in the journals Science Advances and Mucosal Immunology, investigated the impact of wheat fiber—a component abundant in whole-wheat bread but largely absent in “white bread” and other foods made from refined flour.
The researchers determined that the metabolism of wheat fiber by gut bacteria yields biologically active anti-inflammatory metabolites, including polyphenols. These substances then reprogram intestinal immune cells to suppress inflammation, thereby protecting the mice from both acute and chronic intestinal inflammation.
Modifications in food production, particularly the increased use of highly purified wheat products, have led to reduced wheat fiber intake, potentially contributing to the increased prevalence of IBD. Should these findings be validated in humans, it could imply that opting for whole-grain bread, pasta, and other wheat-flour goods instead of white flour alternatives might lower IBD risk. Furthermore, studies suggest that incorporating wheat bran into processed foods could also confer this protective effect.
Wheat fiber represents just one type of dietary fiber that is frequently under-consumed in developed nations. Indeed, most individuals in these countries fail to meet the guidelines set by health organizations recommending a minimum intake of 25–38 grams of fiber daily. These benchmarks are grounded in evidence linking the consumption of fiber-rich plant foods to better health, alongside findings from numerous animal studies demonstrating that dietary fiber supplementation promotes improved well-being.
However, such prior investigations often concentrated on fibers like psyllium, derived from plantain seeds, and inulin, sourced from chicory root—neither of which has historically been a staple in Western diets. Therefore, the finding that wheat fiber, traditionally plentiful in the Western diet, provides such a significant protective benefit is particularly crucial for understanding the role of dietary fiber in gut health.
Moreover, the mechanism through which wheat fiber operates is markedly distinct from those of other fiber types. Specifically, wheat fiber did not exert its effects by boosting short-chain fatty acid levels, as soluble fibers do. Instead, it functioned by liberating bound polyphenols during digestion by gut microbes. In fact, wheat fiber only demonstrated a positive effect in mice that possessed gut microbiota capable of breaking down the wheat fiber to release these polyphenols.
“These results substantiate the hypothesis that the widespread implementation of bran removal during the production of wheat-based foods has contributed to the increased incidence of chronic inflammatory conditions,” commented study co-author Professor Andrew T. Gewirtz of the Institute of Biomedical Sciences at Georgia State University. “Furthermore, they suggest that adding wheat fiber back into processed foods could make them healthier options.”
“The chemical makeup of dietary fibers can be quite intricate,” stated study co-author Song-Eun G. Kim from Weill Cornell Medicine. “But gut bacteria are quite adept at metabolizing them, and the immune system reaps substantial benefits.”
“Indeed, the more we learn about dietary fiber, the more we realize it comprises a highly diverse group of compounds, with fiber from different plants offering distinct health advantages,” Gewirtz added. “A better comprehension of these molecules should eventually enable the creation of healthier processed foods, but for now, choosing whole-grain bread and incorporating a variety of fruits and vegetables into one’s diet seems like a sound strategy.”
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