1. Introduction Functional gastrointestinal disorders (FGIDs) are a heterogeneous group of chronic conditions characterised by persistent and recurrent gastrointestinal symptoms without any apparent structural or biochemical abnormalities [1,2,3]. Affecting between 25 and 40% of the global population, the most common of these conditions include functional bowel disorders and irritable bowel syndrome, as well as functional constipation, functional diarrhoea, and functional bloating [2].
