IBS Days 2026: from pathophysiology to microbiome modulation - Gut Microbiota for Health

IBS Days 2026: from pathophysiology to microbiome modulation  Gut Microbiota for Health

The fifth edition of IBS Days delved into the latest developments in IBS research and clinical management. This article aims to explore causes that can be misdiagnosed as IBS and non-pharmacological strategies targeting gut barrier and gut microbiome dysfunction.

From 15 to 17 June 2026, Gut Microbiota for Health attended IBS Days in Bologna, Italy, which celebrated its 10^th anniversary. Sessions at the conference cross-cut basic, translational, and clinical science in IBS, including epidemiology, genetic influences, gut microbiota, immune pathways, dietary and infectious triggers, biomarker advances, and non-pharmacological interventions.

Is it IBS or a different diagnosis?

It is common for IBS to co-occur with other conditions in which the gut microbiome is directly or indirectly involved. IBS-like symptoms are reported in 30% of IBD patients, particularly those with Crohn’s disease, despite endoscopic remission. An additional risk factor is that approximately 10% of individuals develop IBS following gastrointestinal infection. Increased intestinal permeability is another feature shared by IBS and IBD and may also be triggered by enteric infections. Finally, the immune alterations underlying Crohn’s disease, as well as those induced by acute gastroenteritis, may persist over time as low-grade inflammation, which is considered one of the key mechanisms involved in IBS^.

A global study of 54,127 adults (49.1% women) across 26 countries revealed that greater overlap of disorders of gut-brain interaction (DGBI) across one or more GI regions (esophageal, gastroduodenal, bowel, and anorectal) may lead to increased disease severity and poorer quality of life². In addition, female sex and gender-related factors influence DGBI prevalence, symptom patterns, and comorbidities. IBS also overlaps with endometriosis, with a pooled prevalence of IBS in women with endometriosis of 23.4%³. Endometriosis may share mechanisms with IBS involving sensitization, inflammation, mast cell activation, and an altered gut microbiome. Importantly, IBS may be misdiagnosed in women with ovarian cancer before the age of 50 (hazard ratio = 1.07, 95% CI: 1.04-1.10, p<0.01)⁴. In that regard, National Institute for Health and Care Excellence’s guidelines recommend carrying out appropriate tests for ovarian cancer in any woman of 50 or over who has experienced symptoms that suggest IBS within the last 12 months⁵.

Last, bile acid diarrhea (BAD) should be considered in any child or adult presenting with chronic diarrhea/IBS with diarrhea-particularly postprandial diarrhea, with defecatory urgency and episodes of fecal incontinence-once infectious and inflammatory causes are ruled out. Recent findings suggest that BAD is associated with a gut microbiome with decreased expression of bile acid thiol ligase (involved in the transformation of primary to secondary bile acids) and decreased sulfatases, highlighting the potential of targeting microbial taxa for future treatments^6,7. The role of small intestinal bacterial overgrowth, pancreatic exocrine insufficiency, and symptomatic uncomplicated diverticular disease and their link to IBS remain uncertain.

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