Role of Low-FODMAP diet in functional dyspepsia: "Why", "When", and "to Whom"

Functional dyspepsia (FD) is a frequent disorder of gut-brain interaction, affecting 5-7% of people globally, with significant impairment in quality of life. The management of FD is challenging due to the lack of specific therapeutic approaches. Although food seems to play a role in symptom production, its pathophysiologic role in patients with FD is not fully understood. Most FD patients report that their symptoms are triggered by food, especially in the post-prandial distress syndrome (PDS) group, although evidence to support the use of dietary interventions are limited. FODMAPs can increase production of gas in the intestinal lumen, through fermentation by intestinal bacteria, can exert osmotic effects by increasing water volume and can cause an excessive production of short-chain fatty acids (propionate, butyrate, and acetate). Emerging scientific evidence, confirmed by recent clinical trials, suggest that FODMAPs could be involved in the pathogenesis of FD. Given the consolidated approach of the Low-FODMAP Diet (LFD) in irritable bowel syndrome (IBS) management and emerging scientific evidence regarding the LFD in FD, a therapeutic role of this diet may be hypothesized also in FD, either alone or in combination with other therapies.

AGA Clinical Practice Update on the Role of Diet in Irritable Bowel Syndrome: Expert Review

DESCRIPTION

Irritable bowel syndrome (IBS) is a commonly diagnosed gastrointestinal disorder that can have a substantial impact on quality of life. Most patients with IBS associate their gastrointestinal symptoms with eating food. Mounting evidence supports dietary modifications, such as the low-fermentable oligo-, di-, and monosaccharides and polyols (FODMAP) diet, as a primary treatment for IBS symptoms. The aim of this American Gastroenterological Association (AGA) Clinical Practice Update (CPU) is to provide best practice advice statements, primarily to clinical gastroenterologists, covering the role of diet in IBS treatment.

METHODS

This expert review was commissioned and approved by the AGA CPU Committee and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership, and underwent internal peer review by the CPU Committee and external peer review through standard procedures of Gastroenterology. The best practice advice statements were drawn from reviewing existing literature combined with expert opinion to provide practical advice on the role of diet in treating patients with IBS. Because this was not a systematic review, formal rating of the quality of evidence or strength of the presented considerations was not performed. Best Practice Advice Statements BEST PRACTICE ADVICE 1: Dietary advice is ideally prescribed to patients with IBS who have insight into their meal-related gastrointestinal symptoms and are motivated to make the necessary changes. To optimize the quality of teaching and clinical response, referral to a registered dietitian nutritionist (RDN) should be made to patients who are willing to collaborate with a RDN and patients who are not able to implement beneficial dietary changes on their own. If a gastrointestinal RDN is not available, other resources can assist with implementation of diet interventions. BEST PRACTICE ADVICE 2: Patients with IBS who are poor candidates for restrictive diet interventions include those consuming few culprit foods, those at risk for malnutrition, those who are food insecure, and those with an eating disorder or uncontrolled psychiatric disorder. Routine screening for disordered eating or eating disorders by careful dietary history is critical because they are common and often overlooked in gastrointestinal conditions. BEST PRACTICE ADVICE 3: Specific diet interventions should be attempted for a predetermined length of time. If there is no clinical response, the diet intervention should be abandoned for another treatment alternative, for example, a different diet, medication, or other form of therapy. BEST PRACTICE ADVICE 4: In preparation for a visit with a RDN, patients should provide dietary information that will assist in developing an individualized nutrition care plan. BEST PRACTICE ADVICE 5: Soluble fiber is efficacious in treating global symptoms of IBS. BEST PRACTICE ADVICE 6: The low-FODMAP diet is currently the most evidence-based diet intervention for IBS. Healthy eating advice as described by the National Institute of Health and Care Excellence Guidelines, among others, also offers benefit to a subset of patients with IBS. BEST PRACTICE ADVICE 7: The low-FODMAP diet consists of the following 3 phases: 1) restriction (lasting no more than 4-6 weeks), 2) reintroduction of FODMAP foods, and 3) personalization based on results from reintroduction. BEST PRACTICE ADVICE 8: Although observational studies found that most patients with IBS improve with a gluten-free diet, randomized controlled trials have yielded mixed results. BEST PRACTICE ADVICE 9: There are limited data showing that selected biomarkers can predict response to diet interventions in patients with IBS, but there is insufficient evidence to support their routine use in clinical practice.