HealthDay News — Long-term intake of dietary fiber is associated with a reduced risk of Crohn’s disease, but not ulcerative colitis, according to a study published in the November issue of Gastroenterology.

Ashwin N. Ananthakrishnan, MBBS, MPH, from Massachusetts General Hospital and Harvard Medical School in Boston, and colleagues collected and analyzed data from 170,776 women who participated in the Nurses’ Health Study and were followed for 3,317,425 person-years. A validated semi-quantitative food frequency questionnaire was administered every four years to ascertain dietary information. Medical record review confirmed self-reported Crohn’s disease and ulcerative colitis.

There were 269 and 388 confirmed incident cases of Crohn’s disease and ulcerative colitis for an incidence of 8 and 10 per 100,000 person-years, respectively.

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Intake in the highest (median, 24.3 g/day) versus the lowest quintile of energy-adjusted cumulative average intake of dietary fiber correlated with about a 40% reduction in the risk of Crohn’s disease (multivariate hazard ratio, 0.59; 95% CI: 0.39-0.90). The greatest apparent reduction was seen for fiber derived from fruits, while risk was not modified by fiber from cereals, whole grains or legumes.

Neither total intake of dietary fiber (HR, 0.82; 95% CI, 0.58-1.17) nor intake of fiber from specific sources appeared to be significantly associated with risk of ulcerative colitis.

“Based on data from the Nurses’ Health Study, long-term intake of dietary fiber, particularly from fruit, is associated with lower risk of CD but not UC,” the authors write. “Further studies are needed to determine the mechanisms that mediate this association.”


  1. Ananthakrishnan A et al. Gastroenterology. 2013; 145(5): 970-977.