Dietary protein absorption of the small intestine in human neonates

The intestine plays a key role in the absorption of dietary proteins, which determines growth of human neonates. Bowel resection in the neonatal period brings loss of absorptive and protective surface and may consequently lead to malabsorption of dietary nutrients. However, there are no data on net dietary protein absorption of the small intestine in the period after intestinal surgery in human neonates. We therefore evaluated dietary feeding tolerance and quantified net dietary protein absorption capacity of the small intestine in human neonates in whom a temporary jejunostomy or ileostomy was created.

Seventeen patients were included in the study. We collected small intestinal outflow fluid at the level of the enterostomy weekly for 24-48 hours during weeks 3 through 6 postoperatively. Protein levels in the intestinal outflow fluid were determined by bicinchoninic acid (BCA) assay.

In 14 patients, an enteral intake of >100 mL/kg/d was reached at a median of 17 days (range, 8-32 days) postoperatively. Three patients did not reach this level within the study period. Overall, the net dietary protein absorption capacity was 70%-90% of the total enteral protein intake.

This study demonstrates that the dietary protein absorption capacity of the small intestine is intact in most human neonates after intestinal surgery in a very critical period of their lives. Furthermore, our results do not support the use of hydrolyzed or elemental formula in newborns with an enterostomy to improve amino acid uptake.