BACTERIAL FERMENTATION OF FRUCTOOLIGOSACCHARIDES AND RESISTANT STARCHIN PATIENTS WITH AN ILEAL POUCH-ANAL ANASTOMOSIS

Patients with large bowel disease may undergo heal pouch-anal anastomo sis, in which the colon is removed and part of the distal ileum is use d to construct a pelvic reservoir. Competence of the ileal pouch to fe rment carbohydrates is associated with the absence of pouchitis. Howev er, the extent to which bacterial fermentation takes place and whether it is affected by diet are unclear. We investigated fermentation of t wo nondigestible carbohydrates, fructooligosaccharides and resistant s tarch, in 15 healthy patients with an ileal pouch by using a placebo-c ontrolled crossover design (with glucose as the placebo). Apparent fer ment ability of fructooligosaccharides was 83%; that of resistant star ch was 46%. Resistant starch increased fecal excretion of butyrate by 69% whereas fructooligosaccharides reduced excretion of amino acid-der ived isobutyrate by 94% and of isovalerate by 77%. Fructooligosacchari des also significantly increased fecal weight (651 compared with 541 g /d) and breath-hydrogen excretion (286 compared with 85 ppm x h). Bact erial fermentation of nondigestible carbohydrates in pouches takes pla ce to an appreciable extent and in a substrate-specific manner. The re lation between such fermentation and inflammation of the pouch (pouchi tis) deserves study.