Is The Low Fodmap Diet Effective In The Long Term? The Largest Multicentre Prospective Study

IntroductionThe low FODMAP diet (LFD) has been demonstrated to be effective in managing the symptoms of irritable bowel syndrome (IBS) in the short term. However, data remains limited on the long-term effects of this dietary therapy. The aim of this study was to assess the long-term effect of the LFD on symptom management and adherence.MethodsPatients with IBS who had received LFD advice between 2012–2019 were prospectively recruited at 7 centres in the United Kingdom. Participants were invited to complete dietary questionnaires assessing the LFD at long term follow up (>6 months). Symptoms were assessed using a modified gastrointestinal symptom rating scale (0, none; 1, mild; 2, moderate; 3, severe).Results589 patients were approached, with 154 participants completing the study (76% female, mean age 51±15 years). The mean duration of follow up following initiation of the LFD was 42±28 months. A statistically significant improvement in abdominal pain (2.3±0.8 vs 1.2±0.9, p<0.001), abdominal bloating/distention (2.3±0.8 vs 1.4±1.0, p<0.001) and bowel urgency (2.0±1.1 vs 1.3±1.0, p<0.001) was noted following the LFD at long term versus baseline. 78% (n=120) of individuals reported following an adapted LFD at long term follow up. 60% (n=92) reported grains (wheat, rye, barley) as a trigger for their symptoms, with 64% (n=98) purchasing gluten or wheat free products in the long term.ConclusionThis is the largest study demonstrating the efficacy of the LFD in the long term for individuals with IBS. Adherence to an adapted LFD appears to be good in the long term, with the majority of individuals reporting grains as a trigger and purchasing gluten or wheat free products to manage their symptoms.