Plasma concentrations of carbohydrates and sugar alcohols in term newborns after milk feeding

Abstract

Nonglucose carbohydrates such as galactose, mannose, and inositol play a clinically important role in fetal and neonatal nutrition, though little is known about their metabolism in the neonate. The aim of this study was to determine whether postprandial changes in plasma carbohydrate and sugar alcohol concentrations are affected by clinical variables such as postnatal age (PNA), milk type, feeding volume, or feeding duration in term newborns. Neonates (n = 26) taking intermittent enteral feedings were enrolled. Blood samples were obtained at baseline (immediately before the start of a feeding) and at 2-3 subsequent time points up to 110 min. Postprandial rise was only observed for plasma glucose concentrations [Glu] and plasma galactose concentrations [Gal] and clinical variables did not predict this change. Despite equimolar delivery in milk, the median of [Glu] rise minus [Gal] rise from baseline to second postprandial plasma sample was 674 microM (-38, 3333 microM; p < 0.0001), reflecting efficient hepatic first-pass metabolism of galactose. A significant PNA effect on [Gal] was observed such that for each day PNA there was an 18% decrease in [Gal] (p = 0.03). [Gal] are a function of PNA, suggesting maintenance of a significant ductus venosus shunt in term infants.

Figure 1

Change in [Glu] and [Gal] from baseline to second postprandial plasma sample. Bold horizontal bars show median change for each carbohydrate. Data points with same symbol and shade of gray represent the same subject. For the six patients without a change in [Glu], three patients demonstrated a peak in [Glu] at the first postprandial plasma sample and three patients did not demonstrate a rise in [Glu]. One of the three infants without a [Glu] peak did not have clinical data available on duration of feed or volume of intake. The remaining two patients did not demonstrate significant differences in median duration of feed time or volume of intake compared with the 17 infants with a [Glu] peak (p = 0.60 and 0.79, respectively).

Figure 2

Estimated mean [Gal] (bold line) with 95% confidence intervals (shaded area) and subject specific postprandial data (gray lines) in (A) infants 2 d of age; (B) infants >2 d of age; (C) estimated mean [Gal] over time for PNA 2, 5, 9, 12, and 16 d.