The impact of diet on functional dyspepsia: a critical review of current evidence

This review examines the relationship between diet and functional dyspepsia (FD), a prevalent disorder of gut-brain interaction affecting 8% of the global population and characterised by postprandial fullness, early satiety and epigastric pain or burning. Despite 40-70% of FD patients reporting symptom onset within minutes of eating, standardised dietary recommendations remain limited. The pathophysiological mechanisms underlying food-related symptoms in FD involve complex interactions between altered gastric accommodation and emptying, visceral hypersensitivity, duodenal immune activation and small intestinal microbial dysbiosis. Current evidence most strongly supports dietary lipids as potent triggers of dyspeptic symptoms, likely mediated through cholecystokinin pathways and heightened visceral sensitivity. Additionally, emerging research indicates potential benefits of fermentable carbohydrate restriction, with the low FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) diet showing promise particularly for patients with postprandial distress syndrome. Other dietary factors such as alcohol, coffee, food chemicals, bioactive compounds and meal patterns may also influence FD symptoms though current evidence remains insufficient to inform clinical practice. While existing evidence provides a foundation for understanding diet-symptom relationships in FD, significant gaps remain in translating mechanistic insights into personalised dietary recommendations. Future research should focus on developing evidence-based dietary strategies tailored to FD subtypes, ensuring nutritional adequacy while addressing the complex interplay between nutrient sensing, duodenal immune activation and gut microbiota in symptom generation.