The association between inflammatory potential of diet and disease activity: results from a cross-sectional study in patients with inflammatory bowel disease

BACKGROUND: Diet may play a role in disease status in patients with inflammatory bowel disease. We tested whether the inflammatory potential of diet, based on a summation of pro- and anti-inflammatory nutrients, is associated with disease activity in patients with Crohn’s disease and ulcerative colitis. METHODS: Participants completed a disease activity questionnaire (short Crohn’s Disease Activity (sCDAI) or Patient Simple Clinical Colitis Activity Index (P-SCCAI)) and a Food Frequency Questionnaire (FFQ). FFQ data were used to calculate the Dietary Inflammatory Index (DII) which enables categorization of individuals’ diets according to their inflammatory potential on a continuum from pro- to anti-inflammatory. Associations with disease activity were investigated by multiple linear regression. RESULTS: The analysis included 329 participants; 168 with Crohn’s disease (median sCDAI score 93 [IQR 47–156]), and 161 with ulcerative colitis (median P-SCCAI score 1 [IQR 1–3]). Mean DII was 0.71 ± 1.33, suggesting a slightly pro-inflammatory diet. In Crohn’s disease, the DII was positively associated with disease activity, even after adjustment for confounders (p = 0.008). The mean DII was significantly different between participants in remission and with mild and moderately active disease (0.64, 0.97 and 1.52 respectively, p = 0.027). In ulcerative colitis, the association was not significant. CONCLUSIONS: Disease activity was higher in IBD participants with a more pro-inflammatory diet with statistical significance in Crohn’s disease. Although the direction of causality is not clear, this association strengthens the role for diet in medical treatment, which should be tested in an intervention study.