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P208. Abnormal fibre utilisation and gut transit in ulcerative colitis in remission: A potential new target for dietary intervention

S. James1, P. Gibson1

1Box Hill Hospital, Department of Medicine, Level 5, Clive Ward Building, Victoria, Australia

Background: Dietary supplements of wheat bran (WB) and resistant starch (RS) have potential anti-inflammatory and anti-neoplastic effects on the colonic mucosa by increasing butyrate delivery, and by decreasing phenol exposure and transit time. Such effects have potential benefit in patients with ulcerative colitis (UC). This study aimed to determine the effects WB/RS supplementation on clinical, fermentative and physiological indices.

Methods: An 8 week, single-blind, randomised, cross-over study of 14 patients with ulcerative colitis (UC) in remission (CAI ≤4) and 10 matched healthy subjects comparing the effects from baseline of dietary supplementation with low (5/2 g/day) and high (12/15 g/d) amounts of WB/RS on bowel symptoms, tolerability and disease activity as well as faecal characteristics, fermentative features, whole gut transit time (WGTT) and microbiology (fluorescent in situ hybridisation (FISH) and denaturing gradient gel electrophoresis and polymerase chain reaction (DGGE-PCR)) was undertaken.

Results: Compared with controls, patients with UC had lower mean±SEM dietary fibre intake (17±1 vs 23±3 g/d; p = 0.020, t test) in the background diet, despite a higher faecal output of non-starch polysaccharides (NSP) (9.4±1.8 vs 3.4±0.4 g/d; p = 0.004) and starch (1.3±0.2 vs 0.45±0.08 g/d; p = 0.013). Faecal weight, pH, and concentrations of SCFAs and phenols were similar between the diets in both groups. However, faecal starch and NSP paradoxically fell with high WB/RS supplements in UC, representing an increase of estimated fibre utilisation from 63±5% to 71±5% (p = 0.027) compared with no change in controls (91±1% to 89±2%, p = 0.570). WGTT in UC on the low WB/RS supplements showed wide variation (17 to 96 h) compared with controls (39 to 96 h). With high WB/RS, WGTT consistently decreased (mean 51 to 40 h; p = 0.02) in controls, while its variance in UC considerably reduced (mean 42 h, range 24 to 77 h). Faecal microbiota were unchanged by diets and a prebiotic effect of WB/RS was not observed. Supplements were well tolerated and had no effect on clinical measures of symptoms, disease activity or faecal lactoferrin.

Conclusions: Fibre utilisation in the gut of patients with UC in remission is impaired. High WB/RS supplementation enhanced fibre utilisation and normalised WGTT. As it is well tolerated, its corrective effect on fermentation and transit may translate into therapeutic benefits during remission in patients with UC.