By activating the farnesoid X receptor, psyllium may have anti-inflammatory effects.
Psyllium is a semi-soluble fiber sourced from Plantago seeds. Dietary fiber generally promotes intestinal health, but whether patients with inflammatory intestinal conditions, such as ulcerative colitis, can gain the same benefits has yet to be determined.
A study led by Alexis Bretin, Ph.D., postdoctoral fellow at the Institute for Biomedical Sciences at Georgia State University, tested several types of fiber to gain insight into which fibers might help ease ulcerative colitis and the mechanism by which this may occur.
In the recent study published in Cellular and Molecular Gastroenterology and Hepatology, Bretin and his fellow researchers tested inulin, cellulose, pectin, glucomannan and psyllium in a mouse model. They found that inulin, cellulose, pectin, and glucomannan exacerbated colitis. But psyllium had a protective effect.
When investigating the mechanism by which psyllium conferred its protection, Bretin and colleagues found that psyllium increased serum bile acid levels and, in turn, activated the farnesoid X receptor (FXR), a bile acid receptor. They believe that it is the activation of FXR that quells inflammation and prevents colitis.
The results are from experiments done in mice, so they are preliminary. But Bretin and his colleagues say they suggest that activation of FXR might be pharmacological strategy for treating inflammatory bowel disease (IBD), including ulcerative colitis.
“Our results support the notion that pharmacologic FXR activation might be useful in managing IBD and thus further investigation of its mechanisms of action are warranted,” they wrote, adding that future studies of psyllium in humans should include measurement of serum bile acid and consider roles for FXR activation in mediating impacts of this fiber.
Findings from this study may also inform clinicians and dietitians about the potential benefits of dietary fiber in patients with IBD.
“The notion that fermentable foods might negatively impact IBD has prompted many patients to consume low-fiber diets,” they note, so they are missing out on the “broad array of health benefits provided by fiber, which, at least for some fibers, may include an ability to dampen the inflammation that drives their disease.”