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Fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs), but not gluten, elicit modest symptoms of irritable bowel syndrome: a double-blind, placebo-controlled, randomized three-way crossover trial

https://doi.org/10.1093/ajcn/nqab337Get rights and content
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ABSTRACT

Background

Irritable bowel syndrome (IBS) has been associated with diets rich in fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs), and gluten. Most previous studies have been single-blind and have focused on the elimination of FODMAPs or provocation with single FODMAPs. The effect of gluten is unclear, large trials isolating the effect of gluten from that of FODMAPs are needed.

Objectives

The aims of this study were to ensure high intakes of a wide range of FODMAPs, gluten, or placebo, and to evaluate the effects on IBS symptoms using the IBS-severity scoring system (IBS-SSS).

Methods

The study was carried out with a double-blind, placebo-controlled, randomized 3-way crossover design in a clinical facility in Uppsala from September 2018 to June 2019. In all, 110 participants fulfilling the IBS Rome IV criteria, with moderate to severe IBS, were randomly assigned; 103 (90 female, 13 male) completed the trial. Throughout, IBS participants maintained a diet with minimal FODMAP content and no gluten. Participants were block-randomly assigned to 1-wk interventions with FODMAPs (50 g/d), gluten (17.3 g/d), or placebo, separated by 1-wk washout. All participants who completed ≥1 intervention were included in the intention-to-treat analysis.

Results

In participants with IBS (n = 103), FODMAPs caused higher IBS-SSS scores (mean 240 [95% CI: 222, 257]) than placebo (198 [180, 215]; P = 0.00056) or gluten (208 [190, 226]; P = 0.013); no differences were found between the placebo and gluten groups (P = 1.0). There were large interindividual differences in IBS-SSS scores associated with treatment. No adverse events were reported.

Conclusion

In participants with IBS, FODMAPs had a modest effect on typical IBS symptoms, whereas gluten had no effect. The large interindividual differences in responses to the interventions warrant further detailed studies to identify possible underlying causes and enable individual prediction of responses. This trial was registered at www.clinicaltrials.gov as NCT03653689.

Keywords:

diet
fermentation
functional gastrointestinal disorder
polyols
saccharides
irritable bowel syndrome
FODMAPs
gluten
double-blind
crossover trial

Abbreviations used:

A
FODMAPs
B
gluten
C
placebo in blocks of 12
FODMAPs
fermentable oligo-, di-, monosaccharides, and polyols
IBS-C/D/M/U
irritable bowel syndrome-constipation/diarrhea/mixed/unsubtyped
IBS-SSS
irritable bowel syndrome-severity scoring system
ITT
intention-to-treat
PP
per-protocol
SF-36v2
Short Form 36 version 2
QoL
quality of life.

Cited by (0)

The study was funded by Formas (grant number: 2016-00314) and the Swedish Research Council (grant number: 2017-05840). The funders had no part in the study design, collection, analysis, interpretation of data, writing, or any other type of involvement.

Supplemental Tables 1–5 and Supplemental Methods 1 and 2 are available from the “Supplementary data” link in the online posting of the article and from the same link in the online table of contents at https://academic.oup.com/ajcn/.