Self-reported dietary fructose intolerance in irritable bowel syndrome: Proposed diagnostic criteria.

AIM: To study the criteria for self-reported dietary fructose intolerance (DFI) and to evaluate subjective global assessment (SGA) as outcome measure. METHODS: Irritable bowel syndrome (IBS) patients were randomized in an open study design with a 2 wk run-in on a habitual IBS diet, followed by 12 wk with/without additional fructose-reduced diet (FRD). Daily registrations of stool frequency and consistency, and symptoms on a visual analog scale (VAS) were performed during the first 4 wk. SGA was used for weekly registrations during the whole study period. Provocation with high-fructose diet was done at the end of the registration period. Fructose breath tests (FBTs) were performed. A total of 182 subjects performed the study according to the protocol (88 FRD, 94 controls). RESULTS: We propose a new clinically feasible diagnostic standard for self-reported fructose intolerance. The instrument is based on VAS registrations of symptom relief on FRD combined with symptom aggravation upon provocation with fructose-rich diet. Using these criteria 43 of 77 patients (56%) in the present cohort of IBS patients had self-reported DFI. To improve the concept for clinical evaluation, we translated the SGA scale instrument to Norwegian and validated it in the context of the IBS diet regimen. The validation procedures showed a sensitivity, specificity and κ value for SGA detecting the self-reported DFI group by FRD response within the IBS patients of 0.79, 0.75 and 0.53, respectively. Addition of the provocation test yielded values of 0.84, 0.76 and 0.61, respectively. The corresponding validation results for FBT were 0.57, 0.34 and -0.13, respectively. CONCLUSION: FRD improves symptoms in a subgroup of IBS patients. A diet trial followed by a provocation test evaluated by SGA can identify most responders to FRD.

Effect of fructose-reduced diet in patients with irritable bowel syndrome, and its correlation to a standard fructose breath test.

OBJECTIVES: To perform a validation of dairy registrations for use as diagnostic tool in IBS and fructose malabsorption (FM). To investigate the precision of the fructose breath test (FBT) as compared with symptom score reduction on fructose-reduced diet (FRD) in a cohort of patients with Rome II defined irritable bowel syndrome (IBS). DESIGN: IBS patients diagnosed according to the Rome II criteria and with no organic gastrointestinal disease were enrolled. The patients were randomized in an open study design with a 2 week run-in on IBS diet, followed by 4 weeks w/wo additional FRD. FBT was performed in all patients. Dairy registrations of stool frequency and consistency as well as abdominal pain/discomfort and bloating on a visual analog scale (VAS) were performed during the whole study. RESULTS: A total of 182 subjects performed the study according to protocol (88 FRD, 94 controls). The VAS symptom registration performed well in validation procedures, whereas stool data showed less impressive characteristics. FRD improved symptom scores (abdominal pain/discomfort and bloating) significantly whereas no changes were observed in the control group. The effect of FRD on the stool frequency was modest but no effect was observed on the stool consistency. The FBT did not discriminate between patients with and without effect of FRD, and even in the group with a negative FBT significant improvement of symptom scores was observed. CONCLUSION: VAS measures yield reliable symptom evaluation in dairy registrations of IBS. FRD improves symptom scores in IBS patients independent of results from the FBT.