Centre for Nutrition, Department of Clinical Medicine, University of Bergen, 5009 Bergen, Norway. hanna.dale@outlook.com. Division of Gastroenterology, Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway. hanna.dale@outlook.com. National Centre of Functional Gastrointestinal Disorders, Haukeland University Hospital, 5021 Bergen, Norway. hanna.dale@outlook.com. Centre for Nutrition, Department of Clinical Medicine, University of Bergen, 5009 Bergen, Norway. Department of Gastroenterology, Ankara University Faculty of Medicine, Mamak Ankara 06620, Turkey. Division of Gastroenterology, Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway. National Centre of Functional Gastrointestinal Disorders, Haukeland University Hospital, 5021 Bergen, Norway.