Supplementary Material for: Volatile Organic Compounds in Irritable Bowel Syndrome: Microbial Insights into Gut-Brain Dynamics and Clinical Applications

Background: Irritable Bowel Syndrome (IBS) affects 4.1% of the global population, posing a significant healthcare challenge due to its complex pathophysiology and limited treatment options. Gut microbiota-derived volatile organic compounds (VOCs) are increasingly recognized as key players in IBS, with the potential for non-invasive diagnostics and personalized management.
Summary: This review examines VOCs—such as short-chain fatty acids (SCFAs), hydrocarbons, and alcohols—as microbial metabolites influencing IBS through gut barrier function, inflammation, motility, and gut-brain signaling. Cross-sectional studies highlight the diagnostic accuracy of VOCs (Area Under the Curve (AUC) 0.76-0.99) in distinguishing IBS from healthy controls (HC) and conditions like inflammatory bowel disease (IBD), while longitudinal studies underscore their utility in predicting and reflecting microbial changes to microbiota-targeted therapies. Despite this promise, variability in study designs, methodological inconsistencies, and confounding factors hinder clinical translation.
Key Messages: VOCs illuminate the microbial underpinnings of IBS and its gut-brain interactions, offering a pathway to precise diagnosis and treatment stratification. However, their full potential awaits standardized sampling, analytical protocols, and robust clinical trials to ensure reliability and applicability in IBS care.