Emerging evidence that irritable bowel syndrome & functional dyspepsia are microbial diseases

Gastrointestinal (GI) symptoms in inflammatory bowel disease and gastric or colon cancer also arise through gut-brain interactions (no brain, no pain), so in this sense, FGIDs are not unique. While there are 33 adult and 20 paediatric FGIDs classified in Rome IV [1], among the most prevalent are the irritable bowel syndrome (IBS), characterized by abdominal pain, bowel dysfunction and often bloating and functional dyspepsia (FD), characterized by early satiety, postprandial fullness or epigastric pain [2],[3]. [...]acute and chronic infections, and alterations in the gut microbial environment may be important in the pathogenesis of IBS and FD. Currently, FGIDs are diagnosed by applying symptom criteria (Rome IV)[1], but we speculate that lumping Rome criteria positive cases together in clinical trials is misleading as demonstrated by the small benefit over placebo of all currently FDA-approved therapies for IBS (around 10%); identical symptom complexes may arise from very different gut-brain or brain-gut disease processes, including probably through microbial-driven pathways [2],[3].