FODMAPs—Do they really affect IBS symptoms?

Abstract

Recent knowledgeRecently our research group performed a double-blind, placebo-controlled, randomized 3-way crossover study with a large number of subjects with IBS (7). After introduction of a diet low in FODMAPs excluding gluten, participants were exposed to week-long provocations with high doses of either FODMAPs and gluten or placebo. The exposure dose was 1.5 times the daily intake for an average person. Despite provocation with such high doses, IBS symptoms were only modestly elevated after the FODMAP intervention, and no effect of the gluten intervention was measured by the IBS severity scoring system (IBS-SSS).An interesting observation from this trial was that the symptom severity was much worse at the screening visit [mean (SD); 308 ± 50] than after any of the week-long provocations with FODMAPs, gluten or placebo (240 ± 91, 208 ± 91, 198 ± 91) (Figure 1). Our study is not the first to observe this phenomenon. Hustoft et al. (8) found similar results after introducing a low FODMAP diet and thereafter provoking with one specific FODMAP constituent, i.e., fructo-oligosaccharides (FOS). By comparing baseline (freeliving conditions) to a low FODMAP diet during the 3 week run-in period, the authors concluded that a low FODMAP diet was effective since IBS symptoms were drastically reduced. The limited increase in IBS symptoms after the FOS provocation was hypothesized to relate to Frontiers in Medicine frontiersin.org