The composition of polyunsaturated fatty acids in erythrocytes of lactating mothers and their infants

Abstract

Long‐chain polyunsaturated fatty acids (LCPUFA) in breastmilk, specifically docosahexaenoic acid (DHA), are important for infant brain development. Accretion of DHA in the infant brain is dependent on DHA‐status, intake and metabolism. The aim of this study was to describe changes in maternal and infant erythrocyte (RBC) DHA‐status during the first four months of lactation. We examined 17 mothers and their term infants at 1, 2 and 4 months of age. Milk samples and RBC from the mothers and infants were obtained and analysed for fatty acid composition. Comparative analysis of the results showed that the content of DHA in maternal RBC‐phosphatidylcholine (PE) decreased over the four month period and this was not accompanied by a decrease in DHA in infant RBC‐PE (P = 0.005). The ratio of n‐6 PUFA to n‐3 PUFA increased over time in maternal RBC‐PE, but not in infant RBC‐PE (P < 0.001). The level of 22:5n‐6 and the ratio of LCPUFA to precursor PUFAs in infant RBC was higher than in maternal RBC phospholipids. (P = and P < 0.001 respectively). We found a decrease in the level of LCPUFA in milk, specifically AA. However, we did not observe a significant decrease in milk DHA, which may have been due to two outliers. These results indicate better DHA‐status and a higher n‐3/n‐6 PUFA in RBC of infants than in mothers. Whether these differences reflect preferential n‐3 PUFA transfer via breastmilk or differences in PUFA‐metabolism and utilization remains to be shown.