Modification of the Low FODMAP Diet Is Feasible in the Treatment of Irritable Bowel Syndrome: A Randomised Crossover Study.

BACKGROUND: Irritable bowel syndrome (IBS) can be dietary managed by applying restrictions in the diet of fermentable oligosaccharides, disaccharides, monosaccharides and polyols-the low FODMAP diet. However, many patients have major difficulties integrating the diet into their daily lives. OBJECTIVE: We aimed to investigate if the three carbohydrate groups eliminated in the traditional low FODMAP diet are equally important in relieving gastrointestinal symptoms in IBS. METHODS: Nine patients with IBS according to the Rome IV criteria and referred to specialised diet therapy in private clinics were randomised in a crossover design to three different carbohydrate-modified diets: (A) low polyol diet, (B) low FOS + GOS diet and (C) low standard FODMAP diet for 4 weeks on each diet. Symptoms were assessed by the Birmingham IBS questionnaire and adequate relief (IBS-AR) and quality of life by the IBS Quality of Life Scale questionnaire (IBS-QOL) at baseline and after every intervention period by a dietitian with assessment of the intake by weekly contact. Nonparametric statistical methods were used. RESULTS: Compared to baseline, the low polyol diet did not change the symptoms, but relief was significant on both the low FOS + GOS diet and the low FODMAP diet (p < 0.05) with no difference between these two diets. Clinically relevant symptom relief was experienced by 75% of patients on the low FOS + GOS diet and 62.5% on the low FODMAP diet, but none on the low polyol diet. CONCLUSION: A carbohydrate-modified diet with the exclusion of fructooligosaccharides and galactooligosaccharides (low FOS + GOS diet) reduced gastrointestinal symptoms and improved quality of life equally to the standard low FODMAP diet in patients with IBS. Polyol restriction was of minor importance. The low FOS + GOS diet could be the starting diet in selected patients with IBS. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT05618106.