Protein quality and quantity in preterm infants receiving the same energy intake.
Fifteen low-birth-weight appropriate for gestational age infants, weighing 1.3 to 1.6 kg, were assigned to three isocaloric formulas differing in the quantity and form of nitrogen delivered. A balance study was done between 21 and 30 days after birth. Nitrogen retention expressed as milligram per kilogram per 100 kcal of metabolizable energy was greater with the 60:40 whey/casein and with the casein hydrolysate preparations than with the 20:80 whey/casein formula, which provided the same amount of energy (150 kcal/kg/day) but smaller quantities of protein (3.5 g/kg/day) than the two others (4.3 g/kg/day and 4.4 g/kg/day). Weight gain until discharge from the hospital and increment of height and head circumference over a three-month period showed an advantage of the two formulas providing higher intakes of protein. This study suggests that with high-energy intakes, protein quality does not affect nitrogen retention and growth unless the quantity of protein ingested falls below a critical level.
D002364:Caseins / Q000008:administration & dosage; D004041:Dietary Fats / Q000378:metabolism; D004044:Dietary Proteins / Q000008:administration & dosage*; D002149:Energy Intake; D004734:Energy Metabolism; D006128:Growth; D006801:Humans; D007225:Infant Food; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007234:Infant, Premature; D007785:Lactose / Q000008:administration & dosage; D009584:Nitrogen / Q000378:metabolism; D009753:Nutritive Value; D011492:Protein Hydrolysates / Q000008:administration & dosage; D011897:Random Allocation
D002364:Caseins; D004041:Dietary Fats; D004044:Dietary Proteins; D011492:Protein Hydrolysates; C026375:trypticase-soy broth; D007785:Lactose; D009584:Nitrogen