There has been an increasing interest in the role of fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs) in irritable bowel syndrome (IBS). We report results from the first randomized controlled trial of the low FODMAP diet in US adults with IBS and diarrhea (IBS-D). The objectives were to compare the efficacy of the low FODMAP diet vs. a diet based upon modified National Institute for Health and Care Excellence guidelines (mNICE) on overall and individual symptoms in IBS-D patients.
This was a single-center, randomized-controlled trial of adult patients with IBS-D (Rome III) which compared 2 diet interventions. After a 2-week screening period, eligible patients were randomized to a low FODMAP or mNICE diet for 4 weeks. The primary end point was the proportion of patients reporting adequate relief of IBS-D symptoms ≥50% of intervention weeks 3–4. Secondary outcomes included a composite end point which required response in both abdominal pain (≥30% reduction in mean daily pain score compared with baseline) and stool consistency (decrease in mean daily Bristol Stool Form of ≥1 compared with baseline), abdominal pain and stool consistency responders, and other key individual IBS symptoms assessed using daily questionnaires.
After screening, 92 subjects (65 women, median age 42.6 years) were randomized. Eighty-four patients completed the study (45 low FODMAP, 39 mNICE). Baseline demographics, symptom severity, and nutrient intake were similar between groups. Fifty-two percent of the low FODMAP vs. 41% of the mNICE group reported adequate relief of their IBS-D symptoms (P=0.31). Though there was no significant difference in the proportion of composite end point responders (P=0.13), the low FODMAP diet resulted in a higher proportion of abdominal pain responders compared with the mNICE group (51% vs. 23%,P=0.008). Compared with baseline scores, the low FODMAP diet led to greater reductions in average daily scores of abdominal pain, bloating, consistency, frequency, and urgency than the mNICE diet.
In this US trial, 40–50% of patients reported adequate relief of their IBS-D symptoms with the low FODMAP diet or a diet based on modified NICE guidelines. The low FODMAP diet led to significantly greater improvement in individual IBS symptoms, particularly pain and bloating, compared with the mNICE diet.
1Division of Gastroenterology, University of Michigan Health System, Ann Arbor, Michigan, USA
2University of Michigan Health System, Michigan Clinical Research Unit and Nutrition Obesity Research Center, Ann Arbor, Michigan, USA
3University of Michigan Health System, Nutrition Obesity Research Center, Ann Arbor, Michigan, USA
Correspondence: Shanti L. Eswaran, MD, University of Michigan, Internal Medicine, 1500 E. Medical Center Drive, 3912 Taubman Center, Ann Arbor, Michigan 48109, USA. E-mail: firstname.lastname@example.org
Received 25 March 2016; accepted 10 August 2016
Guarantor of the article: Shanti L. Eswaran, MD.
Specific author contributions: Principal investigator, study design, acquisition of data, analysis and interpretation of data, drafting of manuscript, statistical analysis, obtained funding: Shanti L. Eswaran; study design, dietitian advice, dietary analysis, revision of the manuscript: Theresa Han-Markey; dietitian advice, dietary analysis, revision of the manuscript: Sarah Ball; statistical analysis, revision of the manuscript: Kenya Jackson; principal investigator, study concept and design, analysis and interpretation of data, drafting and revision of the manuscript, supervision of study: William D. Chey.
Financial support: Michigan Nutrition Obesity Research Center Grant (P30 DK089503), Clinical and Translational Science Award Grant (2UL1TR000433-06), Prometheus Therapeutics and Diagnostics (San Diego, CA, USA). The funding of the work was independent of study design, collection, analysis, interpretation of the data, or in the writing of the report.
Potential competing interests: Dr Chey: Consultant and grant funding for Nestle.