STARCH AND DIETARY FIBER COMPONENTS ARE EXCRETED AND DEGRADED TO VARIABLE EXTENTS IN ILEOSTOMY SUBJECTS CONSUMING MIXED DIETS WITH WHEAT OROAT-BRAN BREAD

The study was conducted to determine if the excretion of starch and di etary fiber components varies in ileostomy subjects consuming diets hi gh or low in dietary fiber. Excretion of starch, enzyme-resistant star ch and dietary fiber components was studied in nine human subjects wit h ileostomies, who consumed (in a crossover design) a wheat bread-base d diet (daily intake 274 g starch, 2.4 g enzyme-resistant starch and 1 4.4 g total dietary fiber) and a high fiber diet based on oat-bran bre ad (daily intake 243 g starch, 2.7 g enzyme-resistant starch and 40.2 g total dietary fiber). Food and excreta were collected on d 3 and 17. No significant differences in excretion of starch, enzyme-resistant s tarch or dietary fiber components were found on these 2 d in each diet ary period. When subjects consumed the wheat bread-based diet they exc reted (mean +/-SD) 3.3 +/- 1.7 g starch and 2.4 +/- 0.4 g enzyme-resis tant starch daily, whereas when consuming the oat bran-based diet they excreted 4.5 +/- 3.1 g starch and 2.5 +/- 0.4 g enzyme-resistant star ch. During both dietary periods subjects excreted significantly greate r amounts of certain dietary fiber polysaccharide residues (fucose, ga lactose and uronic acid) than they ingested. This indicates a contribu tion of endogenous and/or microbial material to the dietary fiber valu e in ileostomy effluents. However, significantly less excretion of som e dietary fiber polysaccharide residues, especially glucose residues, during the oat-bran bread-based dietary period was also noted. This wa s presumably caused by a degradation of mixed-linked (1,3),(1,4)-beta- D-glucans.