Competing interests: NJT served as Chair of the Gastroduodenal Committee for Rome IV and received grant support from Rome Foundation; Abbott Pharmaceuticals; Datapharm; Pfizer; Salix; Prometheus Laboratories; Janssen, Commonwealth Laboratories and Falk. Consultant/Advisory Boards: Adelphi Values (Functional dyspepsia (patient-reported outcome measures)); GI therapies; Sax Institute; Allergens; Napo Pharmaceutical; Outpost Medicine; Samsung Bioepis; Yuhan; Synergy; Theravance. Patent Holder: Biomarkers of irritable bowel syndrome (Irritable bowel syndrome) Licensing Questionnaires (Mayo Clinic Talley Bowel Disease Questionnaire–Mayo Dysphagia Questionnaire); Nestec European Patent (Application No 12735358.9); Singapore ‘Provisional’ Patent (NTU Ref: TD/129/17 ‘Microbiota Modulation Of BDNF Tissue Repair Pathway’). GJH served on the Gastroduodenal Committee for Rome III and received unrestricted educational support from Bayer and the Falk Foundation. Research support was provided via the Princess Alexandra Hospital, Brisbane by GI Therapies, Takeda Development Center Asia, Eli Lilly Australia, F Hoffmann-La Roche, MedImmune, Celgene, Celgene International II Sarl, Gilead Sciences, Quintiles, Vital Food Processors, Datapharm Australia, Commonwealth Laboratories, Prometheus Laboratories, Falk, Nestle, and Mylan. Patent Holder: A biopsy device to take aseptic biopsies (US 20150320407 A1).