Research: Two microbiota subtypes identified in irritable bowel syndrome (IBS) with distinct responses to the low FODMAP diet

[Meleber]

Results

Unsupervised analysis of baseline IBS cases pre-diet identified two distinct microbiota profiles, which we refer to as IBSp (pathogenic-like) and IBSh (health-like) subtypes. IBSp microbiomes were enriched in Firmicutes and genes for amino acid and carbohydrate metabolism, but depleted in Bacteroidetes species. IBSh microbiomes were similar to controls. On the low FODMAP diet, IBSh and control microbiota were unaffected, but the IBSp signature shifted towards a health-associated microbiome with an increase in Bacteroidetes (p=0.009), a decrease in Firmicutes species (p=0.004) and normalisation of primary metabolic genes. The clinical response to the low FODMAP diet was greater in IBSp subjects compared with IBSh (p=0.02).

Conclusion

50% of IBS cases manifested a ‘pathogenic’ gut microbial signature. This shifted towards the healthy profile on the low FODMAP diet; and IBSp cases showed an enhanced clinical responsiveness to the dietary therapy. The effectiveness of FODMAP reduction in IBSp may result from the alterations in gut microbiota and metabolites produced. Microbiota signatures could be useful as biomarkers to guide IBS treatment; and investigating IBSp species and metabolic pathways might yield insights regarding IBS pathogenic mechanisms.

gut.bmj.com/content/early/2...

[BabsyWabsy]

Hi Meleber, that is interesting stuff, if a bit technical for some folks. I have always been fascinated by microbiology, and more recently by the microbiome. Tell me, are you a scientist by training?

[Meleber in reply to BabsyWabsy]

Hi, not a scientist, no scientific background at all. I'm just a curious layperson with a wide range of interests.

[BabsyWabsy in reply to Meleber]

Excellent. More people should be curious. It makes life more interesting. So many people glaze over at the mention of any technical stuff. For me, it is fascinating.

[Saraia]

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