Is abnormal 25 g fructose breath test a predictor of symptomatic response to a low fructose diet in irritable bowel syndrome?

Abstract : Background Fructose malabsorption may trigger gastrointestinal symptoms in irritable bowel syndrome patients and a low fructose diet seems to improve digestive symptoms. Aim The aim of our study was to determine whether fructose malabsorption detected by a 25g fructose breath test could be a predictor of the efficacy of a low fructose diet. Methods 88 patients (73 women, median age, 45.5 years, range 18–69) with irritable bowel syndrome according to Rome III criteria were included in this prospective, controlled study. All 88 patients had a 25 g fructose breath test; 37 had a positive test result defining fructose malabsorption. All 88 patients followed a low fructose diet for 2 weeks, blinded to their test results. Patients filled self validated-questionnaires before and at the end of the dietary period. The main outcome measurement was the Irritable Bowel Syndrome-Symptom Severity Score. Results Irritable Bowel Syndrome-Symptom Severity Score significantly decreased in fructose absorbers and fructose malabsorbers after a low fructose diet (−68.0 [−137; 0] versus −73.5 [−173; −11.5]) with no difference according to fructose breath test result (adjusted P = 0.984). Conclusion A positive 25 g fructose breath test is not a predictor of the efficacy of a low fructose diet in irritable bowel syndrome.