Dietary approaches in functional bowel disorders.

Functional bowel disorders, classified as disorders of gut-brain interaction, are highly prevalent and characterized by chronic gastrointestinal symptoms in the absence of identifiable structural abnormalities. The pathophysiology of these disorders is multifactorial. Given this complexity, a symptom-directed treatment approach is essential. As the majority of these patients report food-related symptoms, first-line therapy typically involves the implementation of general dietary and lifestyle advice, as recommended by the British Dietetic Association's (BDA) evidence-based guidelines and U.K's National Institute of Health and Care Excellence (NICE) guidelines. For patients not achieving adequate symptom relief with general guidance, second-line interventions may include targeted exclusion diets, eliminating carbohydrates or proteins. This review focuses on the dietary approaches used in patients with functional bowel disorders, particularly in irritable bowel syndrome (IBS), the most studied disorder. Special attention is given to the low fermentable oligo-, di-, monosaccharides, and polyols (FODMAP) diet is well studied, including its rationale, pathophysiology, effect on gastrointestinal symptoms, and limitations of the diet. Additional dietary strategies are explored, including the starch and sucrose reduced diet, the gluten-free diet or a diet focusing on dietary proteins. Overall, this review synthesizes the current evidence supporting dietary therapies in functional bowel disorders and highlights the need for personalized, multidisciplinary approaches to optimize patient outcomes.