Department of Clinical Medicine, Centre for Nutrition, University of Bergen, Bergen, Norway. Division of Gastroenterology, Department of Medicine, Haukeland University Hospital, Bergen, Norway. National Centre of Functional Gastrointestinal Disorders, Haukeland University Hospital, Bergen, Norway. Firmenich Bjørge Biomarin AS, Ellingsøy, Ålesund, Norway. Department of Clinical Medicine, University of Bergen, Bergen, Norway. National Centre for Ultrasound in Gastroenterology, Haukeland University Hospital, Bergen, Norway. Division of Gastroenterology, Department of Medicine, Ålesund Hospital, Møre & Romsdal Hospital Trust, Ålesund, Norway. Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.