Profile of Intestinal Barrier Functional Markers in Italian Patients with Diarrhea-Predominant IBS: Preliminary Data from a Low-FODMAPs diet Trial

Abstract

The intake of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) is linked to IBS symptoms. Thus, reduced FODMAPs content in the diet may improve symptoms in IBS-D patients, mainly abdominal distension and diarrhea. The mechanism by which the low-FODMAPs diet improves symptoms is still an unsolved matter. On this basis, the study aimed to evaluate variations in the circulating levels of molecules involved in the epithelial barrier integrity and function following a low FODMAPs diet to find new diagnostic markers of IBS. In this exploratory study on the low FODMAP diet, patients suffering from IBS-D according to Rome III criteria were recruited. They performed a validated questionnaire, the Gastrointestinal Symptom Rating Scale (GSRS), the evaluation of the intestinal permeability (lactulose and mannitol absorption test), the measurement of intestinal barrier integrity using Zonulin, Intestinal fatty acid-binding proteins (I-FABP) and Diamine oxidase (DAO) concentrations, as well the skatole and indican evaluation as measure of dysbiosis. A low FODMAPs diet in patients with IBS-D reduced “abdominal pain”, “indigestion syndrome”, and “diarrhea syndrome” GSRS symptom clusters after 90 days of treatment. Besides, this diet improves intestinal functions, possibly moderating the excessive presence of serum and fecal zonulin, regulating mucosal inflammation, and imbalance in the dysbiosis fermentation processes.