Efficacy of Mediterranean Diet vs. Low‐<scp>FODMAP</scp> Diet in Patients With Nonconstipated Irritable Bowel Syndrome: A Pilot Randomized Controlled Trial
Prashant Singh, Gregory D. Dean, Sofia Iram, Westley Peng, Samuel W. Chey, Samara Rifkin, Christine Lothen‐Kline, Jane Muir, Allen Lee, Shanti Eswaran, William D. Chey
Abstract
INTRODUCTION: Mediterranean diet (MD) has been proposed as a dietary therapy for irritable bowel syndrome (IBS) but its efficacy remains unclear. We compared the efficacy of MD to a diet low in fermentable oligo-, di-, monosaccharides, and polyols (LFD). METHODS: In this pilot-feasibility, randomized controlled trial (RCT), adult patients with diarrhea-predominant IBS (IBS-D) or mixed bowel pattern (IBS-M) were randomized to MD versus LFD for 4 weeks. Meals were provided for both groups (ModifyHealth, GA). Daily variables included abdominal pain intensity (API) and bloating, while IBS symptom severity score (IBS-SSS) and IBS adequate relief (IBS-AR) were scored weekly. The primary endpoint was the proportion of patients with ≥ 30% decrease in API for ≥ 2/4 weeks. RESULTS: Of 26 randomized patients, 20 finished the study (10 per group). Seventy-three percent of the MD group met the primary endpoint compared to 81.8% of the LFD group (p = 1.0). Although not statistically significant, a numerically higher proportion of the LFD group reported adequate relief and met the responder endpoint for IBS-SSS (50-point reduction) compared to the MD group (54.6% vs. 27.3% for IBS-AR and 81.8% vs. 45.5% for IBS-SSS, p = 0.39 and 0.18, respectively). The LFD group also had a significantly greater reduction in IBS-SSS score over the 4-week treatment period compared to the MD group (-105.5 vs. -60, p = 0.02). CONCLUSION: MD provides symptom relief in IBS-D and IBS-M; however, the magnitude of relief was higher with the LFD. Larger diet comparison studies in real-world settings are needed before MD can be routinely recommended to IBS patients. TRIAL REGISTRATION: Clinicaltrials.gov: NCT05807919.