Document resource
Introduction Impaired intestinal barrier function, reflected in increased intestinal permeability, is often reported in irritable bowel syndrome (IBS), particularly in diarrhoea-predominant and post-infective subtypes. However, whether improvement in symptoms following dietary intervention is accompanied by measurable changes in intestinal permeability remains unclear. We assess intestinal permeability in IBS patients undergoing low FODMAP diet and examine its association with changes in symptoms.Methods In this ongoing multicentre prospective pre- post intervention study, adults with IBS start a 4-week elimination phase of low FODMAP diet. The primary outcome is change in intestinal permeability, measured using the urinary lactulose: rhamnose assay. Secondary outcomes are changes in IBS symptoms assessed by IBS Symptom Severity Score (IBS-SSS) and IBS Quality of Life (IBS-QoL). Additionally, exploratory permeability assessment using transcutaneous fluorescence spectroscopy (TFS) is carried out. Permeability and symptoms are assessed before and after dietary intervention. Paired data are analysed using Wilcoxon signed-rank tests.Results At the time of reporting, 31 participants completed at least one study visit, and 20 completed paired assessments (i.e. before and after intervention). Mean age of participants was 36.7 years. Male: Female ratio was 8:23. Following the 4-week elimination phase of low FODMAP diet, mean IBS-SSS improved by 29.7% and IBS-QoL by 4.7% (n=20). Where paired permeability results were available, percentage urinary lactulose excretion decreased significantly (0.190 to 0.115; n=13; p=0.011; r=0.64, figure 1A), as did the lactulose: rhamnose ratio (LRR, 0.0364 to 0.0298; n=10; p=0.042; r=0.55, figure 1B). No significant changes were observed in % urinary rhamnose excretion or TFS-derived area under the fluorescence–time curve (figure 1C&D).Conclusions Improvement in IBS symptoms following a low FODMAP diet was accompanied by significant reductions in established markers of intestinal permeability albeit in a small cohort. These findings support an association between treatment response and improved gut barrier function in IBS. Ongoing study will further explore permeability changes across IBS subtypes and evaluate the role of transcutaneous fluorescence spectroscopy as a valid tool for barrier assessment.Abstract P398 Figure 1Changes in intestinal permeability measures following low FODMAP diet. (A) %Lactulose urine excretion (n=13). (B) % Rhamnose urine excretion (n=10). (C) Lactulose: rhamnose ratio (LRR, n=10). (D) AUC: Area under the Curve, derived from TFS fluorescence-time curve (n=13)