Gut microbiome profiles predict response to low FODMAP diet in IBS

Gut microbiota profiles in stool samples of patients with irritable bowel syndrome predicted response to a low FODMAP diet, according to research presented at UEG Week 2016.

“Dietary intervention may reduce IBS symptoms and impact gut microbiota, but the degree to which diet affects gut microbiota is not fully elucidated. Furthermore, factors predicting response to dietary intervention are largely unknown,” Sean M. P. Bennet, MSc, from the University of Gothenburg, Sweden, said during his presentation.

Bennet and colleagues analyzed data from a previous study in which 75 patients with at least moderately severe IBS symptoms were randomly assigned to follow a traditional IBS or low FODMAP diet for 4 weeks. Ultimately, significant improvements in IBS symptoms were reported in comparable proportions in both groups.

“However, there was an unknown impact and involvement of the gut microbiota,” Bennet said. “We therefore wanted to investigate the fecal microbiota composition before and after a low FODMAP diet and traditional IBS dietary advice.”

He and colleagues performed multivariate discrimination analysis relative to a healthy reference group to characterize patient bacterial profiles, which were created using a GA-Map 16S rRNA Dysbiosis Testing of stool samples collected before and after the intervention period.

They found that patients who followed a traditional IBS diet had similar fecal bacterial profiles before and after the intervention, while patients on a low FODMAP diet had different fecal bacterial profiles before and after the intervention.

Nonresponders in the low FODMAP group had more severe dysbiosis than responders, both at baseline (P = .007) and after the intervention (P = .03), but patients who followed a traditional IBS diet had comparable dysbiosis irrespective of responsiveness.

Dysbiosis improved after a traditional IBS diet compared with the low FODMAP diet; among the traditional diet group, 33% had improved dysbiosis, 47% had no change and 20% had worsened dysbiosis, and among the low FODMAP group, these figures were 13%, 45% and 42%, respectively.

“This might be because we saw a significant reduction in Bifidobacterium [P = .0005] after a low FODMAP diet, irrespective of responsiveness,” Bennet said. “However, the traditional IBS diet intervention had no effect on the abundance of Bifidobacterium.”

An evaluation of predictive models showed responders could be discriminated from nonresponders before the low FODMAP intervention, but not the traditional IBS diet, based on bacterial profiles.

“In conclusion, fecal bacterial profiles predict IBS patient responsiveness to a low FODMAP diet,” Bennet said. “The ability of fecal bacteria composition to predict response to a low FODMAP diet in IBS may help in selection of which patients to give this dietary advice.” – by Adam Leitenberger

References:

Bennet SMP, et al. Abstract #3474. Presented at: United European Gastroenterology Week; Oct. 15-19, 2016; Vienna.

Disclosures: The researchers report no relevant financial disclosures.