The low FODMAP diet in clinical practice: where are we and what are the long-term considerations?

A diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) improves functional bowel symptoms and is a second-line dietary management strategy for the treatment of irritable bowel syndrome (IBS). The diet is complex and involves three stages: restriction, reintroduction and personalisation and clinical effectiveness is achieved with dietitian-led education; however, this is not always available. The aim of this review is to provide an update on the evidence for using the low FODMAP diet, with a focus on the impact of FODMAP restriction and reintroduction considering long-term management of IBS in a clinical setting. Randomised controlled trials have assessed symptom response, quality of life, dietary intake and changes to the gut microbiota during FODMAP restriction. Systematic reviews and meta-analyses consistently report that FODMAP restriction has a better symptom response compared with control diets and a network analysis reports the low FODMAP diet is superior to other dietary treatments for IBS. Research focused on FODMAP reintroduction and personalisation is limited and of lower quality, however common dietary triggers include wheat, onion, garlic, pulses and milk. Dietitian-led delivery of the low FODMAP diet is not always available and alternative education delivery methods, e.g. webinars, apps and leaflets, are available but remove the personalised approach and may be less acceptable to patients and may introduce safety concerns in terms of nutritional adequacy. Predicting response to the low FODMAP diet using symptom severity or a biomarker is of great interest. More evidence on less restrictive approaches and non-dietitian-led education delivery methods are needed.