Breast milk retinol concentration in mothers of preterm newborns

Background: Preterm newborns have low vitamin A reserves at birth, which increases their risk of morbidity and mortality. In the absence of supplementation, breast milk is the only source of this nutrient for exclusively breastfed infants. Aims: To assess retinol concentration in preterm milk and the relationship between this retinol concentration and lactation phase, degree of prematurity, and maternal serum retinol level. Study design: Longitudinal study. Subjects: Fifty-eight preterm mothers. Outcome measures: Colostrum (1-3 d), transitional (7-15 d), and mature human milk (30-55 d) samples were collected. Maternal blood was collected once at postpartum. Retinol level was measured using high-performance liquid chromatography. Results: Milk retinol concentration was statistically different between lactation phases (p < 0.001): 2.84 +/- 1.05 mu mol/L in colostrum (58), 3.47 +/- 1.28 mu mol/L in transitional (58), and 2.03 +/- 0.61 mu mol/L in mature milk (30). No difference was found in milk retinol levels between groups with different degrees of prematurity (p > 0.05). Maternal serum retinol (1.82 +/- 0.50 mu mol/L) did not correlate with milk levels (p > 0.05). Conclusions: Retinol level in preterm milk seems to be independent of the degree of prematurity and maternal serum status. A significant increase in micronutrient levels in transitional milk was observed, which is likely to contribute to reserves in the premature liver. (C) 2017 Elsevier Ireland Ltd. All rights reserved.