Treatment of Crohn's Disease with an IgG4-Guided Exclusion Diet: A Randomized Controlled Trial

We previously reported an improvement in symptoms in Crohn's disease following an IgG4-guided exclusion diet in an open-label study. We aimed to evaluate, in a double-blinded randomized sham-controlled setting, the efficacy of IgG4-guided diet in improving quality of life in patients with Crohn's disease. Consecutive patients with Crohn's disease and a Crohn's disease activity index (CDAI) of 80-400 attending tertiary and secondary care centers were screened. All patients had IgG4 titers tested against 16 common food types using ELISA. The true diet group excluded four food types with the highest antibody titers for 4 weeks, and the sham group excluded four foods with the lowest antibody titers. Quality of life was assessed using the Short Inflammatory Bowel Disease Questionnaire (SIBDQ) at beginning and end of the trial. Secondary outcome measures were CDAI, Harvey Bradshaw index, serum C-reactive protein, and fecal calprotectin. One hundred and forty-five subjects were screened and 96 subjects had initial food antibody testing performed with 76 patients completing the study. Milk, beef, pork and egg were the most commonly excluded food types in the true diet group. There was a 3.05 (0.01-6.11) p < 0.05 improvement in SIBDQ and 41 (10.4-71.5) in CDAI p = 0.009. IgG4-guided exclusion diet, as an adjunct, can improve quality of life and symptoms in patients with CD.