Proton nmr studies of betaine excretion in the human neonate: consequences for choline and methyl group supply

Changes in the choline content of human breast milk in the first 3 weeks after birth

“…We showed that betaine (N-trimethylglycine), a breakdown product of choline oxidation, is excreted in large quantities during the neonatal period in humans [6,7,15], reaching a maximum between 2 and 3 months of age (1 mol/mol creatinine), then falling to <0.1 mol/ mol creatinine at 1 year [7]. The same eect is also seen in rats over a similar developmental time scale [6].…”

“…The apparent de®cit between our measurements of urinary betaine output and Zeisel's data for the choline content of breast milk [24], which we found originally [7], seems now to be accounted for by the above data for full-term infants. However, this is not true for premature infants.…”

“…If more than one sample was expressed and analysed on a particular day the bar represents the mean of each of the metabolites and the number above the bar indicates the number of samples included choline per kilogram of body weight is much greater than at 40 weeks. Certain organs have a greater demand for choline at this time, particularly brain and liver [7], which are growing the fastest. Conversely, the intake of choline may be negligible over the ®rst 4 days of life, regardless of the type of nutrition oered, due to sucking immaturity and to frequent intolerance of the required volumes, caused by sluggish gastric and gut motility.…”

“…Previously we investigated the contribution of dietary choline to betaine production in neonates, calculating intake from the data of Zeisel et al [24] and using our own data for betaine output [7]. In this way we calculated that the excretion of betaine exceeded the intake of choline regardless of the type of milk used for feeding during the neonatal period.…”

Nuclear Magnetic Resonance Spectroscopy: A Non-Invasive Probe of Kidney Metabolism and Function

“…In support of the evolutionary concept of osmolyte function, preliminary data derived from the NMR analysis of fetal and pre-term infant urines have led to the hypothesis that myo -inositol, TMAO and taurine may serve as novel biochemical indices of medullary function in the developing human kidney [13]. This metabolic profile changes after birth and betaine is a major urinary metabolite, a pattern not normally found in adult human urine, and possibly related to the immaturity of the neonatal renal cortex to metabolize betaine from dietary choline [14]or to leakage of this compound from cells in the renal medulla. Taken together, these data suggest that osmolytes play an important role during kidney development.…”