[Determination of protein nitrogen utilization with (15N) yeast protein in short bowel syndrome].

The digestive and absorptive capacity for food protein was studied in 8 infants with short bowel syndrome by means of [15N] yeast protein as a tracer substance. The extent of resection ranged from total removal of the small bowel to partial closures of the large bowel by colostomies. The tracer substance was administered as single oral pulse labeling in a dosage of 5 mg 15N/kg. The fecal losses of 15N were extremely high in cases of total and subtotal resection of the small bowel as well as after operative removal of the Bauhins valve. In the entirety they ranged between 3 and 95% of the intake. The corresponding 15N-retention in the protein pool was in the range between 0.1 and 91.6%. Operative findings, nutritional state and passage time were of limited value for the prediction of food protein assimilation. Even residual lengths of 25 cm of the small bowel turned out to be compensated, which was shown in one of the infants by an absorption of 97% and a retention rate of 84%. The oral [15N] yeast protein loading can be considered a reliable test for the evaluation of protein nitrogen absorption and utilization in short bowel syndromes.