1. Introduction
breast milk, term-born
PREMATURE BIRTH, CHOLINE DEFICIENCY, SECONDARY, PRETERM DELIVERY, VERY LOW BIRTH WEIGHT INFANT
Choline is essential for cell membrane formation and methyl transfer reactions, impacting parenchymal and neurological development. It is therefore enriched via placental transfer, and fetal plasma concentrations are high. In spite of the greater needs of very low birth weight infants (VLBWI), choline content of breast milk after preterm delivery is lower (median (p25–75): 158 mg/L (61–360 mg/L) compared to term delivery (258 mg/L (142–343 mg/L)). Even preterm formula or fortified breast milk currently provide insufficient choline to achieve physiological plasma concentrations. This secondary analysis of a randomized controlled trial comparing growth of VLBWI with different levels of enteral protein supply aimed to investigate whether increased enteral choline intake results in increased plasma choline, betaine and phosphatidylcholine concentrations. We measured total choline content of breast milk from 33 mothers of 34 VLBWI. Enteral choline intake from administered breast milk, formula and fortifier was related to the respective plasma choline, betaine and phosphatidylcholine concentrations. Plasma choline and betaine levels in VLBWI correlated directly with enteral choline intake, but administered choline was insufficient to achieve physiological (fetus-like) concentrations. Hence, optimizing maternal choline status, and the choline content of milk and fortifiers, is suggested to increase plasma concentrations of choline, ameliorate the choline deficit and improve growth and long-term development of VLBWI.Choline is essential for the synthesis of the predominant phospholipids phosphatidylcholine and sphingomyelin of cell membranes, for the formation of secretions like bile, surfactant and lipoproteins and for the synthesis of the neurotransmitter acetylcholine [Free, water-soluble choline, due to its high metabolic rate and rapid intracellular uptake, accounts for barely 1% of the total plasma choline pool. However, its availability is crucial to enable the described metabolic processes and the formation of phosphatidylcholine (main fraction of the plasma pool with approx. 88%).The fetus shows a particularly high growth rate between the 24th and 34th week of pregnancy [In case of premature birth, the trans-placental supply of choline via the umbilical cord is suddenly interrupted, so that plasma levels of preterm infants have dropped already by 50% after 48 h; in term infants, this postnatal decline occurs more slowly [The current standard diet of premature infants consists of breast milk enriched with multi-component supplements to meet the infants’ increased nutritional needs. However, an optimization of the choline concentration of both components may be necessary to address choline deficiency in VLBWI.Choline content (median (p25–p75): 158 mg/L (61–360 mg/L)) of breast milk in mothers of preterm infants is lower than in mothers of term-born infants (258 mg/L (142–343 mg/L)), contrasting the higher metabolic needs of VLBWI. Whereas median milk content further decreases during lactation, short term concentrations are relatively stable and can be low or high [