In a preterm infant, which amino acid is separately added to parenteral nutrition solutions due to solubility concerns?

In a preterm infant, which amino acid is separately added to parenteral nutrition solutions due to solubility concerns?

• A. Glycine
• B. Cysteine
• C. Methionine
• D. Phenylalanine

Answer: (B)

In preterm parenteral nutrition, keeping minerals like calcium and phosphate in solution is a major challenge. Cysteine, a sulfur-containing amino acid, is added to the PN solution because it lowers the solution’s pH, which increases the solubility of calcium phosphate and helps prevent its precipitation. This is particularly important in preterm infants, who often require higher mineral intakes and have limited endogenous cysteine synthesis, making exogenous cysteine support essential. Other amino acids like glycine, methionine, or phenylalanine provide nutritional value but do not specifically address the mineral solubility issue in PN solutions.

In preterm parenteral nutrition, keeping minerals like calcium and phosphate in solution is a major challenge. Cysteine, a sulfur-containing amino acid, is added to the PN solution because it lowers the solution’s pH, which increases the solubility of calcium phosphate and helps prevent its precipitation. This is particularly important in preterm infants, who often require higher mineral intakes and have limited endogenous cysteine synthesis, making exogenous cysteine support essential. Other amino acids like glycine, methionine, or phenylalanine provide nutritional value but do not specifically address the mineral solubility issue in PN solutions.