Functional gastrointestinal disorders (FGIDs) contribute up to 60% of gastroenterology outpatient appointments. Diagnosis is based on symptoms (abdominal pain and disordered gastrointestinal habits). FGIDs profoundly affect health-related quality of life both in the pediatric population as well as in adults. They are also associated with a significant economic health care burden. Studies on the etiology of FGIDs focus on visceral hypersensitivity, immune dysregulation, the GI microbiota, altered regulation of the gut-brain axis, and psychosocial factors.
Diet and nutrition are known to play key roles in many chronic gastrointestinal diseases, regarding both pathogenesis and therapeutic possibilities. According to the patient’s opinion, in most FGID cases food intake is considered as a precipitating factor for symptoms, and most of them attribute their symptoms to a specific food. But while diet interventions have been proved beneficial for certain groups such as infants and relevant guidelines have been published, this is not the case for older children and adults. Although there is plenty of information on the association of diet or dietary patterns on the incidence of FGIDs, there is still controversy upon dietary restrictions and other interventions. Nevertheless, personal food–symptom relations may serve as the basis for personalized clinical management.