Influence of casein feeding to very-low-birth weight infants on the plasma amino acid concentrations and the renal amino acid excretion.
The response of plasma and urine amino acid concentrations to a casein formula and to supplemented human milk (both 1.4 gm protein/100 ml) was measured in very-low-birth weight (VLBW) infants (less than 1500 gm) at a postconceptional age of 36 and 40 weeks, respectively. A control group of infants was fed exclusively with fresh human milk (HM). Casein feeding to VLBW infants resulted in prefeeding plasma amino acid profiles and renal amino acid excretions which were not markedly different from those found in infants fed supplemented HM. In comparison with the control feeding group, the infants fed casein or supplemented HM responded with higher total plasma amino acid concentrations (114.4 +/- 33.7 vs 171.0 +/- 36.1 or 167.1 +/- 27.1 mumol/100 ml, respectively) reflecting the higher amount of protein provided by these two feedings. The critical amino acids (sulfur-containing and aromatic amino acids) were metabolized efficiently in infants fed the casein formula. Furthermore, a highly significant relationship (r = 0.795; p less than 0.001) between the plasma concentrations of tyrosine and valine was achieved in all infants independent of the food applied. This relationship could represent a control mechanism to prevent an inordinate influx of aromatic amino acids into the brain. In VLBW infants at a postconceptional age of 36-40 weeks, the metabolic and functional maturity reaches levels which were similar to those found in term newborns.
Noack
J
J
Central Institute of Nutrition, Potsdam-Rehbrücke, Bergholz-Rehbrücke.
Boehm
G
G
D000375:Aging; D000596:Amino Acids / Q000097:blood* / Q000652:urine; D001724:Birth Weight; D002364:Caseins; D004044:Dietary Proteins; D002149:Energy Intake; D005527:Food, Fortified; D006801:Humans; D007225:Infant Food; D007230:Infant, Low Birth Weight / Q000502:physiology*; D007231:Infant, Newborn; D007668:Kidney / Q000502:physiology*; D008895:Milk, Human; D011446:Prospective Studies
D000596:Amino Acids; D002364:Caseins; D004044:Dietary Proteins