Cyst(e)ine Requirements in Enterally Fed Very Low Birth Weight Preterm Infants

Abstract

These data do not support the hypothesis that endogenous cyst(e)ine synthesis is limited in very low birth weight preterm infants with gestational ages of <29 weeks, both at 32 and 35 weeks postmenstrual age. It is safe to conclude that cyst(e)ine requirement is <18 mg/kg per day in enterally fed very low birth weight preterm infants who are older than 32 weeks' postmenstrual age and whose methionine intake is adequate. Therefore, cyst(e)ine is probably not a conditionally essential amino acid in these infants.