Weight Loss

IBS Diets And Gut Bacteria: What’s The Connection?

Irritable Bowel Syndrome (IBS) is a common intestinal disorder affecting approximately 12% of the US population. (1)

The unpleasant symptoms of IBS include:

To prevent, combat, and heal IBS, a unique approach to eating through an IBS diet is part of a lifestyle for good health. Luckily, because of research, every year there are major paradigm shifts in the way we view IBS diets.

Optimum Nutrition Through An IBS Diet 

IBS symptoms can be treated with low-fiber or IBS diet to reduce the colonic microbial fermentation that produces hydrogen and methane, leading to bloating. (4)

Taking gut microbiota into consideration, maybe you have already heard about the diet known as FODMAP – an acronym for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. (2)

FODMAP is an elimination diet, whereby for 2–4 weeks, people on a low FODMAP diet avoid all high FODMAP foods. They then gradually begin reintroducing specific groups of FODMAPs. People with IBS can learn which foods trigger their symptoms.

Those who follow a low FODMAP diet avoid foods that are high in lactose and fructose, certain fruits and vegetables, as well as artificial sweeteners and starches. They usually also avoid wheat-based bread.

Researchers are still trying to discover why a low FODMAP diet helps some people with IBS and not others. (2)

The authors of a study have looked at the bacterial makeup of people with IBS and have examined how it changed in response to following a low FODMAP diet. (4)

The Study

A prospective single-center, case-control study recruited participants from 2016 to 2019. They included adults (18–68 years of age) meeting criteria for diarrhea-predominant, or mixed type IBS, with respective household controls.

Subjects were recruited from outpatient clinics at Cambridge University Hospital in the UK via a social media campaign.

They excluded those with other GI diseases, pregnancy, those already following a restrictive diet, and those taking probiotics or who had taken medications within one month that could potentially modify gut microbiota.

Bacteria in stool samples was assessed from people with IBS who were eating their regular diet. They also examined the bacterial composition of stool samples from a member of the same household, as a control. (4)

Evidence Suggests That IBS Is Connected To The Bacteria In The Gut

Among the IBS participants, they discovered two distinct profiles. One group’s profile was “pathogenic-like.” The other group had a “healthy” personality.

They found that participants with pathogenic-like profiles experienced a more convincing reduction in IBS symptoms than those with health-like profiles. They also found that their gut bacterial makeup and metabolic genes had shifted toward a health-like profile.

The pathogenic-like profile included more bacterial species that are involved in disease – Clostridium difficile, C. sordellii, and C. perfringens, AND exhibited low numbers of beneficial species, such as Bacteroidetes.

Further study of the implicated microbes may give the opportunity to better understand the interaction between diet, microbiota, and the human gut-brain axis that leads to the development of IBS symptoms. (4)

Dietary interventions requiring healthy recipe adaptation can be easy with some expert help and advice. Click here for more information.


  1. https://www.niddk.nih.gov/health-information/digestive-diseases/irritable-bowel-syndrome/definition-facts 
  2. https://www.ncbi.nlm.nih.gov/books/NBK562224/ 
  3. https://www.nhs.uk/conditions/irritable-bowel-syndrome-ibs/symptoms/ 
  4. https://gut.bmj.com/content/early/2021/09/30/gutjnl-2021-325177 

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