The long-term effect and adherence of a low fermentable oligosaccharides disaccharides monosaccharides and polyols (FODMAP) diet in patients with irritable bowel syndrome

Background Short-term trials with a low-FODMAP (fermentable oligosaccharides disaccharides monosaccharides and polyols) diet (LFD) show promising results in the symptomatic management of irritable bowel syndrome (IBS). The present study investigated the long-term adherence to an LFD diet, factors associated with adherence, and associations between LFD and quality of life (QOL), IBS symptoms and disease course on a long-term basis. Methods A retrospective cross-sectional study was conducted. Two hundred and thirty-four patients were enrolled from Ghent University hospital. Health-related QOL, long-term adherence to the LFD, disease course and IBS symptoms were assessed using a validated and self-developed questionnaire. Results Ninety (38.5%) patients completed the questionnaires. The median time span between the first dietary consultation and completion of the questionnaires was 99.5 weeks (approaching 2 years). The predominant disease course was mild IBS with an indolent course (43.0%). Eighty percent reported still following a diet in which certain FODMAP-rich food types are avoided. Eighty patients (88.9%) were satisfied that they follow or had followed the diet. The IBS-QOL did not differ between patients following the diet strictly and patients deviating from the diet (P = 0.669). Patients still following the LFD experienced less severe abdominal pain than patients who stopped following the diet (P = 0.044). Conclusions The long-term adherence and satisfaction with the LFD is high in patients with IBS. Nevertheless, patients indicated that it was difficult to follow the LFD in daily life. Practical issues, social factors and the absence of symptoms were indicated as the main reasons for a drop in adherence.