EXCRETION OF AMINO-ACID-RESIDUES FROM DIETS BASED ON WHEAT-FLOUR OR OAT BRAN IN HUMAN-SUBJECTS WITH ILEOSTOMIES

Objectives: The effect of consumption of a wheat-flour bread-based low -fibre diet (7.8g/day fibre; 1.0 portion) or the same diet in which th e wheat bread was exchanged for a bread based on oat bran with a high fibre content (31.9 g/day fibre; 1.0 portion) on the ileal excretion o f amino acid residues and crude protein was studied. Design: The study was performed as a cross-over design. Setting: The subjects were stud ied as outpatients except on the sampling days when all subjects were admitted to the research ward and stayed in a nearby patient hotel ove rnight. Subjects: Seven men and three women, all proctocolectomised fo r ulcerative colitis, volunteered to participate in the study. One fem ale subject was withdrawn from the study because of inflammation of th e ileal stoma. Interventions: During each dietary period of 3 weeks, f ood and excreta were collected and analysed on days 3 and 17. Results: No significant differences in excretion of crude protein or amino aci ds (free and bound) were found between the two sampling days. Intake a s well as excretion of all analysed amino acids was higher during the high-fibre diet period, although the relative proportion of amino acid s was comparable in the two diets and their corresponding ileal efflue nts. Aspartic acid, glycine, threonine, alanine and serine were found in considerably higher relative proportions in the effluents from the subjects when they consumed each of the two diets than their concentra tions in the diets. The apparent digestibilities were significantly (P < 0.05) lower for all analysed amino acids during the high-fibre diet period. Aspartic acid (10.7%), alanine (9.9%) and glycine (8.5%) show ed a more pronounced decrease than the mean decrease in amino acid dig estibility (6.6%) when subjects consumed the high-fibre diet. Conclusi on: Intake of the oat bran high-fibre diet resulted in significantly l ower amino acid and crude protein digestibility. The relative amino ac id proportions in the diets and their corresponding excretas were, how ever, comparable for the two diets. Sponsorship: This project was supp orted by the Swedish Council of Forestry and Agricultural Research (SJ FR) and Wasabrod AB. Descriptors: amino acids, digestibility, human, i leostomy, oat bran.