Laits maternels et formules lactées 1er âge : péroxydation lipidique

Abstract

Human milk is rich in polyunsaturated fatty acids (PUFA) that are prone to oxidation. We have measured a global (MDA) and specific end-markers of n–6 and n–3 PUFA oxidation, respectively: 4-HNE and 4-HHE, from 7 breast milk samples. Analyses were performed on milk fresh or stored 1 day at 18°C or 7 days at 4°C. Ten infant formulas, liquids or in powder, some supplemented in long chain PUFA, were also studied. The ratio [4-HHE/n–3 PUFA] was 20-fold higher in liquid infant formula than in human milk (0.19 ±0.01μg.g−1). The ratio [4-HNE/n–6 PUFA] was 300-fold higher in liquid infant formula than in human milk (0.004 ±0.000μg.g−1). Storage of human milk did not increase significantly lipid peroxidation, on the contrary to infant formula where MDA increased. The native structure of fat globules in breast milk can take part in its greater protection against oxidation compared to the artificial fat droplets in infant formulas. The health consequences of chronic infant exposure to low dietary doses of lipid peroxidation products should be investigated and infant formulas should be stored in appropriate conditions.