Feffect of Gluten Ingestion and Fodmap Restriction on Intestinal Epithelial Integrity in Patients with Irritable Bowel Syndrome and Self-reported Non-coeliac Gluten Sensitivity.

SCOPE Because epithelial barrier dysfunction has been associated with gluten and FODMAPs, this study aimed to evaluate the effect of alterations in FODMAP intake and blinded, placebo-controlled gluten re-challenge on epithelial barrier function in patients with irritable bowel syndrome (IBS) who self-reported gluten sensitivity. METHODS AND RESULTS Circulating concentrations of markers of epithelial injury (syndecan-1 and intestinal fatty acid-binding protein) and bacterial translocation (lipopolysaccharide-binding protein and soluble CD14) were measured while consuming habitual gluten-free diet and during challenges with gluten and placebo on a background of low FODMAP intake. In 33 patients with IBS and self-reported gluten sensitivity, syndecan-1 concentrations during their habitual diet were elevated (median 43 ng/mL) compared with 23 ng/mL in 49 healthy subjects (p<0.001), but not other markers. On a low FODMAP diet, symptoms were reduced and levels of syndecan-1 (but not other markers) fell by a median 33-35% irrespective of whether gluten was present or not. CONCLUSION Gluten ingestion had no specific effect on epithelial integrity or symptoms in this cohort, but reducing FODMAP intake concomitantly reduced symptoms and reversed apparent colonic epithelial injury. These findings highlight the heterogeneity of populations self-reporting gluten sensitivity and implicate FODMAPs in colonic injury in IBS. This article is protected by copyright. All rights reserved.