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PLASMA FREE AMINO ACID CONCENTRATIONS OF BREAST‐FED INFANTS
Author(s) -
LINDBLAD B. S.,
ALFVÉN G.,
ZETTERSTRÖM R.
Publication year - 1978
Publication title -
acta pædiatrica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 115
eISSN - 1651-2227
pISSN - 0803-5253
DOI - 10.1111/j.1651-2227.1978.tb17819.x
Subject(s) - taurine , valine , cystine , medicine , endocrinology , amino acid , excretion , lactation , urine , breast milk , glycine , urinary system , biochemistry , pregnancy , chemistry , biology , enzyme , cysteine , genetics
. Photometric determination of alpha‐amino nitrogen in peripheral venous plasma and urine from 20 healthy, full‐term infants, 1–5 months of age, showing normal growth and development during an uncomplicated lactation, revealed lower plasma levels than what has been found in adults, or 3.7±1.1 mg/100 ml, and a urinary excretion of 41 + 14 mg/24 hours. Ion‐exchange chromatography of deproteinized peripheral venous plasma showed low valine concentrations, an increased glycine/valine ratio and high cystine and very high taurine levels when compared to the levels of healthy American infants of comparable ages fed 3‐3.5 g/kg of cow‐milk protein. The findings indicate that a formula based on cow‐milk protein should optimally contain only 1.0–1.2 g protein/100 ml provided that it is “humanized” not only with regard to the lactalbumin/casein ratio, but also to the cystine and taurine content. The pattern of the plasma concentrations of free amino acids reported in the present investigation may be used as a normal reference for breast‐fed infants.