January 02, 2018
Clinical Gastroenterology and Hepatology
Abstract
BACKGROUND & AIMS
We investigated the effects of a diet low in fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs) vs traditional dietary recommendations on health-related quality of life (QOL), anxiety and depression, work productivity, and sleep quality in patients with irritable bowel syndrome and diarrhea (IBS-D).
METHODS
We conducted a prospective, single-center, single-blind trial of 92 adult patients with IBS-D (65 women; median age, 42.6 years) randomly assigned to groups placed on a diet low in FODMAPs or a modified diet recommended by the National Institute for Health and Care Excellence (mNICE) for 4 weeks. IBS-associated QOL (IBS-QOL), psychosocial distress (based on the Hospital Anxiety and Depression Scale), work productivity (based on the Work Productivity and Activity Impairment), and sleep quality were assessed before and after diet periods.
RESULTS
Eighty-four patients completed the study (45 in the low-FODMAP group and 39 in the mNICE group). At 4 weeks, patients on the diet low in FODMAPs had a larger mean increase in IBS-QOL score than did patients on the mNICE diet (15.0 vs 5.0; 95% CI, -17.4 to -4.3). A significantly higher proportion of patients in the low-FODMAP diet group had a meaningful clinical response, based on IBS-QOL score, than in the mNICE group (52% vs 21%; 95% CI, -0.52 to -0.08). Anxiety scores decreased in the low-FODMAP diet group compared with the mNICE group (95% CI, 0.46-2.80). Activity impairment was significantly reduced with the low-FODMAP diet (-22.89) compared with the mNICE diet (-9.44; 95% CI, 2.72-24.20).
CONCLUSIONS
In a randomized, controlled trial, a diet low in FODMAPs led to significantly greater improvements in health-related QOL, anxiety, and activity impairment compared with a diet based on traditional recommendations for patients with IBS-D.
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This study by Eswaran et al is an extension of a previously published trial of the effects of a low-FODMAP diet compared with a modified NICE (mNICE)–recommended diet in IBS. The prior report documented no significant differences in the primary endpoints; that is, proportion of those reporting adequate relief or composite endpoint responders. Nonetheless, the low-FODMAP diet resulted in a significantly higher proportion of abdominal pain responders and greater improvements for bloating, consistency, frequency, and urgency in the low-FODMAP group than in the mNICE group.
The current paper documents improvements in other trial secondary endpoints that were prespecified in the registered trial (NCT01624610). Between-treatment comparisons showed a mean 10-point (of a 0–100 scale) improvement in IBS-QOL and a significant reduction in anxiety, but not in depression, sleep or fatigue scores, or work absenteeism or presenteeism. In the QOL domains, there were no improvements in health, worry, or relationship scores. There was no correlation between symptom response (abdominal pain or adequate relief) and improvement in QOL or psychological indices. The study limitations included insufficient power to assess secondary endpoints, incomplete blinding as diets were not supplied to participants, and that instruction on the two diets was provided by specially trained research dieticians who were not blinded to the study intervention. The mechanisms of potential benefit of low-FODMAP diet are unclear.
Other clinical trials have shown no difference in relief of IBS symptoms between a low-FODMAP and either mNICE diet or, in a separate trial, gut-directed hypnotherapy. Given the significant likelihood of un-blinding of dietary treatment, the jury is still out whether a low-FODMAP diet, which has been associated with reduced intake of fiber, calcium, iron, zinc, folate, B and D vitamins, and natural antioxidants, is more efficacious than the far less restrictive mNICE diet.