Ratio of non-protein calories to grams of amino acids and amino acid blood levels in preterm infants receiving parenteral nutrition.

This article focuses on the impact of the non-protein calorie to grams of amino acids ratio (NPKcal:g AA) in parenteral nutrition solutions on amino acid and acylcarnitine levels in preterm infants ≤31 weeks postmenstrual age. The study found that lower NPKcal:g AA ratios were associated with higher levels of ornithine, citrulline, and blood urea nitrogen, suggesting increased amino acid oxidation and urea cycle activation, while higher ratios correlated with better metabolic profiles and possibly improved head circumference growth. Despite no significant differences in weight and length growth velocities among groups, the findings indicate that inadequate non-protein caloric intake in parenteral nutrition may impair amino acid metabolism and affect growth outcomes. The authors suggest an optimal NPKcal:g AA ratio of at least 18–20:1, potentially greater than 21:1, to support amino acid utilization and recommend further research on growth and neurodevelopmental outcomes in very low birth weight infants receiving parenteral nutrition.