Avoidance of Fiber Is Associated With Greater Risk of Crohn's Disease Flare in a 6-Month Period.

BACKGROUND & AIMS Chronic inflammatory bowel diseases (IBDs) have been associated with an abnormal mucosal response to the gastrointestinal microbiota. Although dietary fiber affects the gastrointestinal microbiota, there is limited information on the role of fiber on IBD activity. We investigated factors associated with fiber consumption and whether it was associated with flares in patients with IBD. METHODS We collected a completed 26-item dietary survey from 1619 participants in the Crohn's and Colitis Foundation of America Partners Internet cohort (Crohn's disease, 1130; ulcerative colitis/indeterminate colitis, 489). Eligible individuals were in remission based on disease activity index at baseline and completed a follow-up survey 6 months later. Fiber and whole grain consumption were categorized into quartiles and deciles. Disease flare at 6 months was defined as a disease activity index score exceeding remission cutoff values, and/or an IBD-related surgical procedure or hospitalization since baseline. RESULTS Participants with longer duration of disease, past history of surgery, and past IBD hospitalization ate less fiber. The risks for disease flare differed by disease type. Compared with those in the lowest quartile of fiber consumption, participants with Crohn's disease in the highest quartile were less likely to have a flare (adjusted odds ratios [OR], 0.58; 95% confidence interval [CI], 0.37-0.90). Participants with Crohn's disease who reported that they did not avoid high-fiber foods were ∼40% less likely to have a disease flare than those who avoided high-fiber foods (adjusted OR, 0.59; 95% CI, 0.43-0.81). There was no association between fiber intake and flares in patients with ulcerative colitis (adjusted OR, 1.82; 95% CI, 0.92-3.60). CONCLUSIONS Intake of dietary fiber is associated with reduced disease flares in patients with Crohn's disease, but not UC. Recommendations to limit dietary fiber should be re-evaluated.