Nutritional Therapies in Irritable Bowel Syndrome (IBS)

Irritable bowel syndrome (IBS) affects 1-in-10 people, with most patients identifying food as a key symptom trigger. While dietary intervention is central to IBS management, existing approaches — including the low FODMAP diet (LFD) and gluten-free diet (GFD) — carry significant drawbacks: complexity, cost, social restrictions, nutritional risk, and gut dysbiosis. A series of randomised controlled trials systematically evaluated multiple dietary therapies. Head-to-head comparisons of traditional dietary advice (TDA), LFD, and GFD found all three to be effective, but TDA emerged as the most patient-friendly, and it is recommended as the first-line option. A recent UK trial demonstrated that the Mediterranean diet is also effective in IBS, positioning it as an additional first-line alternative before escalating to more restrictive therapies. Mechanistic analyses reveal important insights into nutritional and gut microbiome changes underpinning these effects. Key Learning Points · TDA should be considered the first-choice dietary therapy in IBS, with LFD and GFD reserved as second-line options · The Mediterranean diet is effective in IBS and offers practical advantages, warranting inclusion in future clinical guidelines · Dietary interventions in IBS produce measurable changes in nutritional status and gut microbiota, offering mechanistic understanding of therapeutic effects