Milk protein quantity and quality in low-birth-weight infants. IV. Effects on tyrosine and phenylalanine in plasma and urine

David K. Rassin, Gerald E. Gaull, Neils C R Räihä, Kirsti Heinonen

Research output: Contribution to journalArticle

85 Scopus citations


Well, appropriate-for-gestational age, low-birth-weight infants were divided into three gestational agegroups and assigned randomly within each age group to one of five feeding regimens: pooled human milk (BM); formula 1 (F1)=1.5 gm/dl protein, 60 parts bovine whey proteins: 40 parts bovine caseins; F2=3.0 gm/dl, 60:40; F3=1.5 gm/dl, 18:82; F4=3.0 gm/dl, 18:82. Plasma and urine concentrations of tyrosine and phenylalanine were far higher in the infants fed F1 to F4, especially F2 and F4, than in the infants fed BM. These findings offer further evidence for the limited capacity of the low-birth-weight infant to catabolize tyrosine. Infants fed F3 had significantly higher plasma tyrosine concentrations than infants fed F1, and those fed F4 had higher concentrations than those fed F2. Thus, increased plasma tyrosine concentrations in low-birth-weight infants are related directly both to the quantity and to the quality of the protein in their diets.

Original languageEnglish (US)
Pages (from-to)356-360
Number of pages5
JournalThe Journal of pediatrics
Issue number3
StatePublished - 1977
Externally publishedYes


ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health

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