Efficacy of a Low-FODMAP Diet for Coeliac Patients with Persistent IBS-like Symptoms despite a Gluten-Free Diet: A Systematic Review

: Background: Persistent symptoms in coeliac disease (CD) can be due to not only poor gluten-free diet (GFD) adherence and complications of CD, but also functional gastrointestinal disorders such as irritable bowel syndrome (IBS). Although the role of a low fermentable oligo-, di-, and monosaccharides and polyols (FODMAP) diet is well-established in IBS, little data are available on its role in coeliac patients with persistent IBS-like symptoms despite a GFD. Methods: We systematically reviewed the literature in accordance with the PRISMA guidelines for studies evaluating the role of FODMAPs and/or a low-FODMAP diet in coeliac patients with persistent symptoms. PubMed and Embase were searched from inception to 16 January 2024 for eligible full-text papers. The study protocol was registered on Open Science Framework. Results: A total of 239 records were identified, and six papers were included. Of these, four were interventional studies comparing a low-FODMAP GFD to a regular GFD for persistent symptoms in 115 total coeliac patients (two randomized controlled trials and two open-label studies). A low-FODMAP GFD for a minimum of 4 weeks was significantly more effective than a regular GFD in reducing symptoms (p < 0.05 in 3/4 studies). Dietary FODMAP content of a conventional GFD was significantly lower than that of non-coeliac patients on a gluten-containing diet (both p < 0.05), especially regarding high-FODMAP grain products. However, coeliac patients consumed more servings of fruits/vegetables high in FODMAP. No relationship between FODMAP intake and persistence of symptoms was reported. Conclusions: A low-FODMAP diet may be beneficial for uncomplicated celiac patients with persistent IBS-like symptoms despite strict adherence to a GFD.