Human milk protein and medium-chain triglyceride oil supplementation of human milk: plasma amino acids in very low-birth-weight infants.

Fifty-one very low-birth-weight infants (birth weight less than 1,520 g) randomly fed either human milk or human milk supplemented with human milk protein and/or with medium-chain triglyceride (MCT) oil were observed. Plasma amino acids from these infants were studied at 2, 8, and 10 weeks. Medium-chain triglyceride oil supplementation had minimal or no influence on plasma amino acids. Human milk protein supplementation resulted in increased concentrations of all amino acids at all ages studied. The concentrations were 1.5- to threefold as compared with values in infants not given protein supplements. However, the concentrations of methionine, tyrosine, phenylalanine, and lysine remained far below values considered harmful. The age at which maximal plasma amino acid concentrations in infants given human milk protein supplementation occur coincides with the age of the lowest serum albumin concentrations in infants fed only human milk. This suggests that high plasma amino acid concentrations may hasten albumin synthesis in very low-birth-weight infants.