Long-term double-blind study on the influence of dietary fibres on faecal bile acid excretion in juvenile ulcerative colitis

Abstract

A double-blind cross-over long-term trial (18 months) with randomized supplementation with wheat fibre or ispaghula for two periods of six months, separated by a six-month wash-out period with placebo, was performed in ten patients with juvenile ulcerative colitis to study the effect on faecal bile acid (BA) excretion. All patients were in remission since 0.5–2 years and orally treated with sulphasalazine. The average intake of either fibres was 16 g day⁻¹. Faecal samples were collected (72 h) before and after each fibre period. Faecal water were prepared by centrifugation of faeces at 15 000 g for 2 h. BA in faeces and faecal water were studied using capillary column gas-liquid chromatographymass spectrometry. Faecal excretion of total BA were not significantly changed by the two fibres. Supplementation with wheat fibre, but not with ispaghula, decreased the faecal concentration of total BA by 43% (p < 0.05), unconjugated BA by 41% (p < 0.01), and taurine conjugated BA by 58% (p < 0.05). Addition of wheat fibre decreased the concentration of chenodeoxycholic acid by 66% (p < 0.05) and isomers of cholic acid by 51% (p < 0.05) in faeces. The mean faecal water concentration of taurine-conjugated BA decreased by 55% when wheat fibre was added (p < 0.05) and the concentration of isomers of deoxycholic acid increased by 39% when ispaghula was supplemented (p < 0.05). The ratio isomeric deoxycholic acid to deoxycholic acid in faecal water increased significantly when wheat fibre was added (p < 0.05). The percentage distribution of secondary and ketonic BA was not influenced by the dietary fibre supplementation. The concentration of BA in faeces and faecal water decreased only by wheat fibre, suggesting that it is superior in obtaining an affect on faecal BA concentration.

Key Words:

• faecal water
• ispaghula
• mass spectrometry
• remission
• wheat fibre