Exploring Gut Microbiota Composition as an Indicator of Clinical Response to Dietary FODMAP Restriction in Patients with Irritable Bowel Syndrome
A diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) may relieve symptoms of irritable bowel syndrome (IBS). However, nutritional counseling is resource-demanding and not all patients will benefit.
To explore whether gut microbial composition may identify symptom response to a low-FODMAP diet in patients with IBS.
Patients were recruited consecutively to participate in a 4-week FODMAP-restricted diet. Response to diet was defined as ≥ 50% decrease in IBS symptom severity scores (IBS-SSS) compared to baseline. Fecal microbiota were analyzed by a commercially available method (the GA-map™ Dysbiosis Test), assessing 54 bacterial markers targeting more than 300 bacteria at different taxonomic levels.
Sixty-one patients (54 F; 7 M) were included: 32 (29 F; 3 M) classified as responders and 29 (25 F; 4 M) as non-responders. Ten of the 54 bacterial markers differed significantly between responders and non-responders. Based on median values (used as cutoff) of responders for these 10 bacterial markers, we constructed a Response Index (RI): Each patient was given a point when the value for each selected bacterial marker differed from the cutoff. These points were summed up, giving an RI from 0 to 10. Patients with RI > 3 were 5 times more likely to respond (OR = 5.05, 95% CI [1.58; 16.10]), and the probability to respond was 83.4%, 95% CI [61.2–94%].
Gut microbial composition, assessed by using a new RI, may constitute a tool to identify patients that are likely to respond to dietary FODMAP restriction.
KeywordsClinical nutrition Functional gastrointestinal disorders Gut microbiome Irritable bowel severity scoring system
The work of the clinical dietician (TK) and the microbial DNA analyses were funded by Genetic Analysis AS, Oslo, Norway. Otherwise, the study was funded by Lovisenberg Diaconal Hospital, Oslo, Norway.
JV conceived and designed the study, performed the data collection, and wrote the manuscript. MCS performed the statistical analyses and wrote the manuscript. TK guided the patients throughout the dietary intervention. GAL interpreted the data and contributed to critical revision. AR conceived and designed the study, and recruited the patients. All authors reviewed and approved the final version of the manuscript to be published.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All procedures performed in the study were in accordance with the ethical standards of the Regional Committee for Medical Research Ethics (REK Sør-Øst, Reference No. 2013/454) and with the 1964 Helsinki Declaration and its later amendments.
- 1.Sperber AD, Dumitrascu D, Fukudo S, et al. The global prevalence of IBS in adults remains elusive due to the heterogeneity of studies: a Rome Foundation working team literature review. Gut 2016.Google Scholar
- 17.Altman DG, Machin D, Bryant TN, Gardner MJ. Statistics with confidence. 2nd ed. New York: BMJ Books; 2000.Google Scholar
- 23.Hustoft TN, Hausken T, Ystad SO, et al. Effects of varying dietary content of fermentable short-chain carbohydrates on symptoms, fecal microenvironment, and cytokine profiles in patients with irritable bowel syndrome. Neurogastroenterol Motil 2016.Google Scholar
- 28.Bennet SMP, Bohn L, Storsrud S, et al. Multivariate modelling of faecal bacterial profiles of patients with IBS predicts responsiveness to a diet low in FODMAPs. Gut 2017.Google Scholar