Introduction
breast milk fortifiers
The supply of the essential nutrient choline is often insufficient, especially in preterm infants [Prenatally, choline is actively transported to the fetus via the placenta, resulting in high plasma-free choline concentrations of ⁓ 40 µmol/L [During the third trimester, volume of parenchyma, being rich in PC/SPH, increases. Particularly, brain gray matter becomes enriched in PUFA-PC [The US Food and Drug Administration defined choline as an essential nutrient in 1998 and adequate intakes (AI) were defined by the National Academy of Medicine of the USA (NAM) and the European Food Safety Authority (EFSA). The requirements are defined by age, sex, life conditions and genetics, with tightly defined AI and high upper tolerable limit (UL) values [Total choline intake through breastmilk and current formulas is lower than prenatal supply. Choline content of breast milk fortifiers varies greatly, resulting in infants’ plasma-free choline concentrations being only half those of the fetus, and even decreasing postnatally [In this study, we aimed to investigate potential differences in the plasma kinetics of choline, betaine and PC following supplementation of ‘free’ choline as a salt compared to its major physiologic water-soluble and lipophilic organic esters. We used their stable-isotope-labeled derivatives, namely D9-choline chloride, D9-phosphoryl-choline, D9-GPC and D9-POPC. This was to inform future enteral choline supplementation in preterm infants’ nutrition.