A high-fiber, low-fat diet improves the symptoms and metabolic profile of patients with Crohn's disease

BackgroundCrohns disease (CD) is characterized by intestinal inflammation. Diet is a risk factor for inflammatory bowel diseases such as CD and represents a promising adjunctive treatment, yet there are few well-controlled dietary intervention studies in CD patients. Fiber may have beneficial effects; however, most CD patients are told to avoid high-fiber foods. We conducted a longitudinal patient-preference study to examine the effect of a catered low-fat, high- fiber diet (the Mi-IBD diet) on CD symptoms, inflammation, and the microbiome. MethodsCD patients (n=73) received one-time diet counseling (Group 1, n=23), the Mi-IBD diet (Group 2, n=26), or the Mi-IBD diet along with a healthy household control (Group 3, n=24 patient- HHC dyads). The Mi-IBD diet was catered for 8 weeks, and CD symptoms were recorded. Serum samples were collected to measure inflammatory marker levels and evaluate systemic changes via proteomic analyses (SomaScan Discovery v4.1 assays). Stool samples were collected to perform metabolomic analyses. ResultsAt baseline, CD patients had a low-fiber, high-fat diet. One-time diet counseling did not result in dietary changes. In contrast, catering led to marked dietary changes in CD patients (increased fiber intake, decreased fat intake; all ps < 0.001) and high adherence rates (96%). Group 3 exhibited improvements in CD symptoms (PRO2 and sCDAI scores). Proteomic analysis revealed higher baseline serum levels of proinflammatory proteins (SAA and CRP) in CD patients than in HHCs; these levels decreased with the catered diet. The diet also improved fecal metabolites related to protein and energy metabolism as well as markers of oxidative stress and inflammation in CD patients. ConclusionA nonpharmacological approach involving a high-fiber, low-fat diet to manage CD was well tolerated, even by patients with fibrostenotic CD. These findings fill a gap in development of dietary recommendations for CD patients. Clinical trial registrationThis trial was registered at ClinicalTrials.gov (ID: NCT04213729).