Abstract
Background: Irritable Bowel Syndrome (IBS) affects 7-10% of the population. Patients have identified that food is a trigger for their symptoms. There is emerging evidence that a diet low in fermentable oligosaccharides, monosaccharides, disaccharides and polyols (FODMAP) is beneficial. This Randomised Controlled Trial (RCT) aimed to compare symptom severity and quality of life of participants following a low FODMAP diet and those following their customary diet at three months. The hypothesis was that a reduction in dietary FODMAP molecules would cause a reduction in symptom severity and an improvement in quality of life in participants with IBS.
Methods: Participants with IBS according to Rome III criteria were recruited from gastroenterology outpatients, general practice and through advertising in a community newspaper. Participants completed the IBS SS (IBS symptom severity scoring system,0- 500 points), IBS QoL (IBS quality of life questionnaire, 0-100) and a FODMAP specific food frequency questionnaire at baseline and three months. They were randomised to either education with the dietitian on a low FODMAP diet or a waiting list control.
Results: Out of 117 screened patients, 50 participants were recruited for the study, 32 of whom had diarrhoea predominant IBS. In the intervention group (n=23) there was a statistically significant reduction in IBS SS from 275.6 (±63.6) to 128.8 (±82.5) (p<0.0001) which remained significant when controlling for the reduction in the control group (n=27) (p=0.002). There was also a significant improvement in the IBS QoL in the intervention group from 68.5 (±18.0) to 83.0 (±13.4) (p<0.0001). This remained statistically significant when controlling for the change in the control group (p<0.0001). There was a statistically significant relationship between the reduction in FODMAP intake and the reduction in IBS SS score (p=0.02). There was no difference in bloating and the severity of pain when compared to the control group but there was a significant reduction in the frequency of pain when compared to the control group (p<0.0001). The low FODMAP diet consumed by participants was nutritionally adequate.
Conclusion: This study demonstrated that a low FODMAP diet reduced symptom severity and improved quality of life in participants with IBS while ensuring a nutritionally adequate diet.