The Effect of a FODMAPs Diet on Symptom Production and the Gut Microbiome in Patients with IBS.
June 4, 2015 in Quebec City
Keith McIntosh, MD, FRCPC,
Theresa Schneider BASc, MPH, RD, Hotel Dieu Hospital Kingston
Ian Spreadbury PhD, GIDRU Queen’s University
Stephen Vanner, MD, FRCPC, Queen’s University
Objective: With increasing evidence that the gut microbiome and foods such as fermentable oligo, di, and monosaccharides and polyols (FODMAPs) contribute to symptoms in patients with irritable bowel syndrome (IBS), this study set out to determine if FODMAPs modulates symptoms in patients with IBS Methods: This prospective, randomized trial comparing the effect of low-FODMAP and high-FODMAP diets on IBS patients (ROME III diagnostic criteria), randomized subjects to either diet for a total of 3 weeks, regardless of their previous reported fodmap intake. A RD taught the diets in a 30 min session: with a booklet, food diary, foods to choose and avoid lists and menu choices. The low diet contained 2 servings of wheat/day. The previously validated IBS Symptom Severity Questionnaire measured symptoms. The gut microbiome was assessed indirectly by measuring H2 production as the change in the area under the curve (AUC) of H2 ppm for a 5 hour, 10g Lactulose Breathe Test (LBT). The Dietitian developed a Dietary Fodmap Code (DFC) (intake over a 7 day period using Canada’s Food Guide and Estimates of Food Frequencies) to verify dietary compliance. Results: 40 patients were enrolled with 20 randomized to the low FODMAPs and 20 to the high FODMAP diet. For the analysis, 16 and 18 respectively were used. Baseline symptom scores and LBT H2 AUC were similar between groups. At the end of the study, symptom scores had decreased by 31.1% in the low FODMAP group (p < 0.0001), versus no change in the high FODMAP group (+4.48%, p = 0.58). Neither diets produced any significant changes in H2 AUC (-12.12%, p = 0.39 and +4.8%, p = 0.75 respectively). Conclusions: The analysis shows a low FODMAP diet taught by an RD leads to a significant reduction in IBS symptom severity after 3 weeks.