Why your gut bugs matter for IBS and Crohn’s

People with inflammatory bowel disease often have a more permeable intestinal barrier, and this same condition is commonly observed in other chronic diseases.

Fecal calprotectin and lactoferrin are proteins measured in stool that can accurately differentiate between inflammatory bowel disease and irritable bowel syndrome because they are elevated in the presence of neutrophil-mediated intestinal inflammation, which does not occur in irritable bowel syndrome.

Certain strains of Escherichia coli bacteria, known as AIEC, are found in people with Crohn’s disease but not in those with irritable bowel syndrome. These bacteria attach to specific receptors in the gut lining, penetrate the intestinal barrier, persist inside immune cells, and contribute to ongoing inflammation in individuals with particular genetic backgrounds.

People with irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) have different types and amounts of gut bacteria. IBD is linked to fewer overall bacterial species and less of a specific beneficial bacterium, while IBS is linked to higher levels of bacteria that produce methane and hydrogen sulfide, suggesting different underlying biological processes in each condition.

Fecal microbiota transplantation has shown some ability to reduce symptoms of mild-to-moderate ulcerative colitis in controlled studies, but it is not currently advised for routine patient care because results vary, procedures are not uniform, and long-term risks are unknown.