People with a distinctive and abnormal profile to their gut bacteria could benefit from a low FODMAP diet to help treat their irritable bowel syndrome, a new study has found.
Researchers from the Wellcome Sanger Institute, the University of Cambridge, and Addenbrooke’s Hospital in Cambridge, used in-depth microbiome analysis to identify two groups of people with IBS with different compositions of gut bacteria.
This, they say, is not only helping to shed light on the mechanisms behind IBS, but it could also potentially provide new treatment options.
The research, published in today’s edition of Gut, describes one group, which made up about half of all patients, as benefitting from a low FODMAP diet after they were found to have a distinctive gut bacteria profile.
The team said improvement also led to a shift in the gut bacteria towards a more normal, “healthy” profile, which means these bacteria could be used as a biomarker to identify who are more likely to benefit from the low FODMAP diet.
It could also enable people to have tailored treatment plans and could provide a new target for IBS therapies.
Joint first author Dr Stephen Moss, consultant gastroenterologist at Addenbrooke’s Hospital, said: “IBS affects roughly one in 10 people globally, with limited effective therapies. The condition often has a huge impact on quality of life and it’s only been over the last decade or so, that research has started to investigate the potential mechanisms that are involved.”
The low FODMAP diet has been shown to improve IBS in many cases, but it is challenging to follow because it avoids certain fruits, vegetables, milk, and wheat products.
In this study, patients and those who lived with them were investigated and both groups stuck to a low FODMAP diet for four weeks.
An in-depth genomic and functional analysis was carried out in 112 participants’ microbiomes and this novel method identified two distinct microbiome profiles: in one group, the bacterial makeup of the gut was similar to healthy individuals and in the second group, known as IBSP, the makeup was different.
While the researchers found 75% of overall cases improved with the low FODMAP diet, those with an IBSP microbial profile had a dramatic change in their gut bacteria.
After four weeks, those with IBSP had a microbiome that resembled a healthy individual, and these individuals reported a higher degree of symptom improvement.
Joint first author Dr Kevin Vervier, senior staff scientist at the Wellcome Sanger Institute, said: “Functional, genomic and mechanistic analyses have allowed us to uncover more about which bacteria are potentially contributing to IBS and also which metabolites are involved.
“We are hopeful that this research could lead to a personalised approach to IBS, which is supported by genomic research. We would like to thank the participants in this study for taking part, as our research would not have been possible without them.”
Professor Miles Parkes, joint senior author and consultant gastroenterologist at Addenbrooke’s Hospital, added: “The low FODMAP diet has previously shown to improve many of the symptoms of IBS, but very little is known about why this happens, or why some people respond better to it than others.
“Through our research, we were able to identify a biomarker that makes it possible to stratify different types of IBS and then identify who would benefit most from this diet. This is potentially very useful in ensuring that patients don’t undergo this restrictive and challenging diet without benefits.”
Vervier K, Moss S, Kumar N, et al. Two microbiota subtypes identified in irritable bowel syndrome with distinct responses to the low FODMAP diet. Gut 23 November 2021; doi: 10.1136/gutjnl-2021-325177
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