IS A SIMPLIFIED LOW FODMAP RESTRICTION PHASE POSSIBLE? RESULTS FROM A MULTI-CENTER, DOUBLE-BLIND, PILOT-FEASIBILITY, RANDOMIZED CONTROLLED TRIAL

Introduction: The current ‘step-down’ approach to implementing a low FODMAP diet (LFD) in which all 5 FODMAP groups are restricted presents significant practical challenges for patients, A ‘step-up’ approach has been proposed where only 1-2 FODMAP groups are initially restricted and further restriction is only done if necessary. Based on the results from our recent double-blind reintroduction study, we conducted a multi-center, double-blind, pilot feasibility randomized controlled trial comparing the efficacy of a 4-week ‘FODMAP-simple’ restriction (restricting only fructans and galactooligosaccharides) vs. a traditional LFD restriction in patients with diarrhea-predominant IBS (IBS-D).
Methods: Adult ROME IV IBS-D patients (18-65 years) at two centers with an average daily abdominal pain intensity (API) score of ≥3 during 7-day baseline period were randomized to receive traditional LFD vs. FODMAP-simple diet for 4 weeks. To standardize nutrient content and improve compliance, prepared meals and snacks (Epicured,NY) were provided and daily food diaries were recorded. Daily outcomes included API, abdominal discomfort, bloating, and bowel habits while weekly outcome included IBS Symptom Severity Score (IBS-SSS).
Results: Of 35 randomized patients, 24 finished the study and were included in the analysis (10 in traditional LFD and 14 in the FODMAP-simple group). Both groups had a similar intake of calories, macronutrients, and FODMAPs pre-intervention but differed in their FODMAP intake post-intervention. Ninety percent (9/10) in the traditional LFD group met the primary endpoint (≥30% reduction in API for ≥2 of 4 weeks) compared to 71.4% (10/14) in the FODMAP-simple group (P=0.36). The proportion of patients meeting the responder definition for abdominal discomfort, and bloating were similar between the traditional LFD and FODMAP-simple groups (80% vs. 78.6% for discomfort and 80% vs. 71.4% for bloating respectively, P=1.00 each). The mean percent change in API, abdominal discomfort, and bloating from baseline to week 4 were similar between the two groups (Table 1). Fifty percent (5/10) in the traditional LFD group met the responder definition for stool consistency (≥50% reduction in the number of days with BSFS 6-7 stool for ≥2/4 weeks) compared to 14.3% (2/14) in the FODMAP simple group (P=0.08). All the traditional LFD patients were IBS-SSS responders (50-point decrease) compared to 77% of the FODMAP-simple patients (P=0.23).
Discussion: This is the first study to show that a simplified LFD restriction (restricting only fructans and galactooligosaccharides) is feasible and is similarly effective to a traditional LFD in improving abdominal symptoms in IBS-D patients. Our data suggests a 'step-up' approach to LFD may be feasible in IBS-D. Larger studies are needed to validate our findings and evaluate the incremental benefits of the 'step-up' approach.