Longitudinal study of vitamins A, E and lipid oxidative damage in human milk throughout lactation

Little is known about the intensity of oxidative damage in human milk resulting from maternal oxidative stress. The aim of our study was to explore the changes in Total Antioxidant Status (TAS) and concentrations of antioxidative vitamins and isoprostanes (markers of oxidative stress) in human colostrum and mature milk.

The study included 49 postpartum women with normal, spontaneous full term delivery. The exclusion criteria included active and passive smoking, acute and chronic disorders, and pharmacotherapy other than vitamin supplementation. Colostrum samples were collected on the 3rd day after delivery and breast milk samples between the 30th and the 32nd day after delivery. TAS of colostrum/breast milk was determined by Rice-Evans and Miller method. The amount of vitamins A and E was measured by HPLC. Isoprostane concentrations in colostrum/mature milk and urine were determined immunoenzymatically.

No significant differences were observed in maternal dietary intakes of vitamins A and E determined prior to the colostrum and mature milk sampling. The TAS of mature milk was significantly higher compared to colostrum (P=0.002), while vitamin A and E concentrations were significantly lower (P=0.003 and P=0.001). Although the isoprostane concentration of mature milk was significantly higher than the colostrum concentration, this difference was not significant (P=0.129).

Human milk is a source of antioxidative vitamins and their concentrations decrease throughout the lactation, while their total antioxidative properties increase. The phase of lactation does not affect the degree of human milk's lipid oxidative damage.