Exclusive elemental diet impacts on the gastrointestinal microbiota and improves symptoms in patients with chronic pouchitis.

Background: Treatment resistant chronic pouchitis causes significant morbidity. Elemental diet is effective treatment for Crohn's disease. Since pouchitis shares some similarities to Crohn's disease we hypothesised that elemental diet may be an effective treatment.

Method: Seven pouchitis patients (with ulcerative colitis) were studied. All had active pouchitis with a pouch disease activity index (PDAI) ≥7. Exclusion criteria were recent NSAIDs, antibiotics or probiotics. Sufficient elemental diet to achieve energy requirements was provided. Flexible-pouchoscopy was performed, and the Cleveland Global Quality of Life score (CGQoL), Pouch Disease Activity Index (PDAI) and BMI were recorded at baseline and following 28 days of elemental diet. Faecal samples were also collected at these time points and analysed for major bacterial groups using culture independent fluorescence in situ hybridisation. Data were analysed using Wilcoxon's signed-rank test.

Results: Following 28 days of exclusive elemental diet, median stool frequency decreased from 12 to 6 per day (p=0.028), median clinical PDAI decreased from 4 to 1 (p=0.039). There was no significant difference in quality of life scores or PDAI before and following treatment. There was a trend towards an increase in the concentration of Clostridium coccoides-Eubacterium rectale (median 7.9 to 8.5 log₁₀/g, p=0.08) following exclusive elemental diet.

Conclusion: Treatment with four weeks elemental diet appeared to improve the symptoms of chronic pouchitis in some patients but is not an effective strategy for inducing remission. Although a potential symptom modifier, elemental diet cannot be recommended for the routine treatment of active pouchitis.