Amino acid composition in parenteral nutrition

Abstract

Commercial parenteral nutrition (PN) solutions contain L-amino acid preparations that typically include all nine essential amino acids (AA) and varying numbers of nonessential amino acids over a range of concentrations. Data remain limited from rigorous randomized clinical trials (RCTs) and comparative effectiveness research (CER) on optimal doses of amino acids in PN. In addition, with some exceptions (e.g., glutamine (GLN)), little rigorous research on the clinical and metabolic impact of altered specific amino acid composition of the PN amino acid component has been performed in children or adults. An exception is the growing number of studies on the efficacy of GLN added to PN and emerging amino acid dose-response studies in very low birth weight infants requiring PN. Parenteral GLN added to complete PN may confer benefit in selected patients; however, several recent studies show no difference in clinical outcomes in intensive care unit (ICU) patients with use of PN supplemented with GLN dipeptides, while high-dose intravenous GLN dipeptide combined with high-dose enteral GLN in adult critically ill patients with multiple organ failure and/or shock may be deleterious. Additional data to define optimal GLN dosing and the patient subgroups may benefit after organ recovery are needed. Very limited data on the efficacy of PN supplemented with branchedchain amino acids (BCAA), arginine, taurine, or cysteine are available. Few clinical efficacy data are available to conclusively guide total or specific amino acid dosing in adult and pediatric patients in PN. Adequately powered RCTs are needed to better determine optimal amino acid dosing and PN amino acid composition in critically ill patients who require PN support.