Which two amino acids are higher in standard parenteral amino acid solutions for neonates than those from standard adult parenteral amino acids?

• A. Taurine
• B. Tyrosine
• C. Taurine and Tyrosine
• D. Cysteine and Methionine

Answer: (C)

Neonatal parenteral nutrition commonly includes higher amounts of certain amino acids because newborns, especially preterm infants, have immature metabolism and rapid growth that make some amino acids conditionally essential. Tyrosine becomes essential in neonates because the enzyme that converts phenylalanine to tyrosine is not fully developed, so providing extra tyrosine supports protein synthesis and growth. Taurine is also supplied in higher amounts because it plays important roles in bile acid conjugation, retinal and neurodevelopment, and neonates cannot synthesize it in sufficient quantities. These developmental needs explain why both tyrosine and taurine are increased in neonatal PN compared with standard adult PN.