Excretion of amino acid residues from diets based on wheat flour or oat bran in human subjects with ileostomies.
OBJECTIVE
The effect of consumption of a wheat-flour bread-based low-fibre diet (7.8 g/day fibre; 1.0 portion) or the same diet in which the wheat bread was exchange for a bread based on oat bran with a high fibre content (31.9 g/day fibre; 1.0 portion) on the ileal excretion of amino acid residues and crude protein was studied.


METHODS
The study was performed as a cross-over design.


METHODS
The subjects were studied as outpatients except on the sampling days when all subjects were admitted to the research ward and stayed in a nearby patient hotel overnight.


METHODS
Seven men and three women, all proctocolectomised for ulcerative colitis, volunteered to participate in the study. One female subject was withdrawn from the study because of inflammation of the ileal stoma.


METHODS
During each dietary period of 3 weeks, food and excreta were collected and analysed on days 3 and 17.


RESULTS
No significant differences in excretion of crude protein or amino acids (free and bound) were found between the two sampling days. Intake as well as excretion of all analysed amino acids was higher during the high-fibre diet period, although the relative proportion of amino acids was comparable in the two diets and their corresponding ileal effluents. 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 concentrations 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%) showed a more pronounced decrease than the mean decrease in amino acid digestibility (6.6%) when subjects consumed the high-fibre diet.


CONCLUSIONS
Intake of the oat bran high-fibre diet resulted in significantly lower amino acid and crude protein digestibility. The relative amino acid proportions in the diets and their corresponding excretas were, however, comparable for the two diets.
Abrahamsson
M
M
Department of Food Science, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Aman
P
P
Hallmans
G
G
Zhang
J X
JX
Tidehag
P
P
D000368:Aged; D000596:Amino Acids / Q000378:metabolism*; D018554:Avena / Q000378:metabolism*; D004043:Dietary Fiber / Q000008:administration & dosage* / Q000378:metabolism*; D004044:Dietary Proteins / Q000378:metabolism; D005243:Feces / Q000737:chemistry; D005260:Female; D006801:Humans; D007081:Ileostomy / Q000009:adverse effects*; D007408:Intestinal Absorption; D008297:Male; D008875:Middle Aged; D014908:Triticum / Q000378:metabolism*
D000596:Amino Acids; D004043:Dietary Fiber; D004044:Dietary Proteins