This 2025 review explores how gut microbiota imbalance (dysbiosis) may contribute to the development and persistence of irritable bowel syndrome (IBS). Patients with IBS often demonstrate reduced microbial diversity and compositional changes in key bacterial taxa, along with altered production of metabolites such as short-chain fatty acids (SCFAs), bile acids, and tryptophan derivatives. These microbial and metabolic changes are associated with low-grade inflammation, impaired epithelial barrier function, abnormal motility patterns, and amplified pain signaling. However, findings remain heterogeneous, and no single, reproducible “IBS microbiome signature” has been consistently identified across studies.

The review highlights probiotics and probiotic-derived metabolites (postbiotics) as potential adjunctive therapeutic strategies aimed at restoring microbial balance and targeting underlying IBS mechanisms. Specific strains—particularly selected Bifidobacterium and Lactobacillus species—may improve symptoms through multiple pathways, including strengthening epithelial barrier integrity, reducing pro-inflammatory signaling, modulating immune and enteric nervous system activity, and influencing bile acid metabolism and SCFA production. Some data suggest strain-specific benefits for bloating, abdominal pain, and stool patterns, though effects vary by IBS subtype. While early results are encouraging, questions remain regarding optimal strain selection, dosing strategies, treatment duration, patient selection, and long-term safety. Larger, well-controlled clinical trials are needed to clarify efficacy and guide routine integration into clinical practice.

Reference: García Mansilla MJ, Rodríguez Sojo MJ, Lista AR, et al. Exploring Gut Microbiota Imbalance in Irritable Bowel Syndrome: Potential Therapeutic Effects of Probiotics and Their Metabolites. Nutrients. 2024 Dec 31;17(1):155. doi: 10.3390/nu17010155. PMID: 39796588; PMCID: PMC11723002.

Irritable Bowel Syndrome (IBS) is a common gastrointestinal disorder (often more frequent in women) whose prevalence varies by diagnostic criteria and geography. Under Rome IV it’s classified as a disorder of gut-brain interaction and is characterized by recurrent abdominal pain associated with defecation and/or changes in stool frequency or form, after basic evaluation excludes organic disease and alarm features. Patients are grouped by predominant bowel pattern (IBS-D, IBS-C, IBS-M, IBS-U), and symptoms can overlap with other gut-brain interaction disorders. The cause is multifactorial, involving altered gut-brain signaling, visceral hypersensitivity, stress/anxiety, dietary triggers, and shifts in the gut microbiome, so care is usually tailored and multimodal.

Diet is one of the most important—and most challenging—tools in IBS management because responses differ widely from person to person. The review emphasizes that dietary strategies should be individualized, flexible, and ideally supervised to avoid overly restrictive “one-size-fits-all” plans and potential downsides (nutrient gaps, social burden, or disordered eating). Low-FODMAP has the strongest evidence for short-term symptom control and is typically used in phases (restriction, structured reintroduction, personalization). Mediterranean-style patterns may be more sustainable but often require modification for FODMAP sensitivity. Gluten- or lactose-free approaches can help selected subgroups, soluble fiber is often useful (especially in IBS-C), insoluble fiber may worsen symptoms for some, and IgG-guided elimination remains controversial. Overall, the goal is a practical, personalized plan integrated with broader clinical and behavioral support.

Reference: Siragusa N, Baldassari G, Ferrario L, et al. The Ten Dietary Commandments for Patients with Irritable Bowel Syndrome: A Narrative Review with Pragmatic Indications. Nutrients. 2025 Jul 30;17(15):2496. doi: 10.3390/nu17152496. PMID: 40806081; PMCID: PMC12348238.

This comprehensive systematic review and meta-analysis pooled data from 80 population-based studies encompassing more than 260,000 individuals and estimated a global irritable bowel syndrome (IBS) prevalence of 11.2%. However, prevalence varied markedly (1%-45%) depending on geographic region, diagnostic criteria, and study methodology. Rates were lowest in Southeast Asia (7%) and highest in South America (21%). Diagnostic framework substantially influenced estimates, ranging from 8.8% with Rome I criteria to 14% using Manning criteria. Prevalence was generally higher when symptoms were self-reported through questionnaires rather than interviewer-administered, and when shorter minimum symptom-duration thresholds (e.g., 3 months vs 12 months) were applied. Among IBS subtypes, IBS-D was frequently the most common pattern reported, although studies including IBS-U demonstrated a more balanced distribution across IBS-C, IBS-D, IBS-M, and IBS-U.

Women had a significantly higher likelihood of IBS than men (OR 1.67; 95% CI, 1.53-1.82), while individuals aged ≥50 years had lower odds compared with younger adults (OR 0.75; 95% CI, 0.62-0.92). Socioeconomic status did not show a consistent association with prevalence, although few studies reported these data. Despite substantial heterogeneity across studies, the findings underscore IBS as a prevalent, globally distributed disorder associated with meaningful quality-of-life impairment and economic burden. Variability by geography, methodology, and diagnostic criteria highlights the importance of standardized definitions and the need for additional research in underrepresented regions.

Reference: Lovell RM, Ford AC. Global prevalence of and risk factors for irritable bowel syndrome: a meta-analysis. Clin Gastroenterol Hepatol. 2012 Jul;10(7):712-721.e4. doi:10.1016/j.cgh.2012.02.029. PMID: 22426087.