Colonic Microbiota Dysbiosis Tied to Constipation-Predominant IBS Pathophysiology
Irritable bowel syndrome with constipation (IBS-C) is increasingly linked to disruptions in the colonic microbiota, according to a literature review published in the British Journal of Hospital Medicine. Researchers from Sofia Medical University (Bulgaria) and Aintree University Hospital (UK) determined that microbiome alterations may underlie gut motility dysfunction and symptom severity in IBS-C.
Study Findings: Microbiota Alterations in IBS-C
The review synthesizes emerging evidence on colonic microbial imbalances in adults with IBS-C. Patients consistently demonstrate reduced populations of beneficial microbes, including Bifidobacterium and Lactobacillus, coupled with increased inflammatory taxa such as Enterobacteriaceae and Escherichia coli.
These dysbiotic patterns are associated with diminished short-chain fatty acid (SCFA) production, which may impair colonic transit and contribute to constipation. Altered SCFA levels also appear to disrupt enterochromaffin cell function and serotonin signaling in the gut, mechanisms implicated in sluggish peristalsis and visceral hypersensitivity among IBS-C patients.
The authors note that increased intestinal permeability and low-grade inflammation correlate with changes in gut-brain axis signaling, potentially worsening abdominal pain and bloating. Despite consistent trends, the review highlights methodological heterogeneity across microbiome studies, including variable sampling techniques and analytic pipelines, which limits direct comparison and clinical translation.
Clinical Implications for Gastroenterology Practice
For clinicians managing adults with constipation-predominant IBS, these findings underscore the importance of considering gut microbiota as a modifiable contributor to symptom burden. The reviewed evidence supports monitoring dietary patterns known to influence microbial diversity, such as fiber intake and prebiotic consumption, given their association with SCFA production and motility regulation.
Therapeutic strategies aimed at microbiota modulation — including probiotics, synbiotics, and targeted dietary interventions — may hold promise, although robust randomized trials are needed to define optimal strains, dosing, and duration.
Further research should prioritize longitudinal studies to capture microbiota dynamics over time and assess whether sustained modulation correlates with improved bowel function and quality of life in IBS-C populations.
Colonic microbiota dysbiosis appears central to IBS-C pathophysiology, affecting motility, inflammation, and gut-brain interactions. While clinical application remains exploratory, this review lays the groundwork for personalized microbiome-focused therapies in constipation-predominant IBS.
Reference:
Roy YJ, Mirani Y, Raju J, et al. The role of colonic microbiota in constipation predominant irritable bowel syndrome: A literature review. Br J Hosp Med (Lond). 2025;86(10):1–11. doi:10.12968/hmed.2025.0184.
