A diet low in fermentable oligo‐, di‐, monosaccharides and polyols improves abdominal and overall symptoms in persons with all subtypes of irritable bowel syndrome

Background A diet low in fermentable oligo‐, di‐, monosaccharides and polyols (LFD) improves symptoms in patients with irritable bowel syndrome (IBS). Previous studies have focused on patients with IBS and diarrhea (IBS‐D). It is unclear whether LFD is effective for IBS with constipation (IBS‐C) or IBS with mixed bowel habits (IBS‐M). This open‐label, real‐world study evaluates the relative effectiveness of the LFD among IBS subtypes. Methods This study analyzes data from a service that provides low‐FODMAP meals to individuals with IBS. Participants met with a registered dietitian and completed the IBS symptom severity survey (IBS‐SSS) before and after undergoing a 2–4‐week period of FODMAP restriction. The primary endpoint was the proportion of participants with ≥50‐point decrease in IBS‐SSS between the three IBS subtypes. Key Results After FODMAP restriction, 90% of participants with IBS‐D, 75% with IBS‐C, and 84% with IBS‐M met the primary endpoint (p = 0.045). Similar improvement was seen for a 100‐point decrease, but the difference between IBS subtypes was not significant (p = 0.46). After FODMAP restriction, all groups had statistically significant improvement in total IBS‐SSS as well as individual symptom categories. Improvement in IBS‐SSS subcategories was similar among the groups except for the categories of bloating severity (IBS‐M had greatest improvement) and bowel movement satisfaction (IBS‐C had less improvement). Conclusion & Inferences Though the proportion of responders was highest for IBS‐D and lowest for IBS‐C, the LFD led to robust improvement in overall symptoms in all IBS subtypes. Key individual symptoms also showed significant improvements in all IBS subtypes. “An investigation into the effectiveness of the low‐FODMAP diet for IBS subtypes; this work finds that a low‐FODMAP diet is effective for all subtypes of IBS.”