Fatty acids and their sn-2 positional distribution in breast milk and their association with edible oils in maternal diet: a study of five regions in China

This study analyzed total fatty acids (FAs) and their sn-2 positional distribution in triacylglycerol (TAG) in breast milk (n = 300) from three lactational stages in five regions of China, and further investigated their association with the effect of the type of edible oil consumed by lactating mothers. A total of 33 FAs including 12 saturated fatty acids (SFAs), 8 monounsaturated fatty acids (MUFAs), and 13 polyunsaturated fatty acids (PUFAs) were determined using GC. Breast milk from different regions showed significant differences in MUFAs, sn-2 MUFAs, and PUFAs (P < 0.01, P < 0.001, and P < 0.001). The results showed that 10 : 0, 18 : 0, 18 : 1 n-9, 18 : 2 n-6 (LA), and 18 : 3 n-3 (ALA) were mainly esterified at the sn-1 and sn-3 positions; 20 : 4 n-6 (ARA) seemed homogeneously esterified at all sn-positions in TAG, while 14 : 0, 16 : 0, and 22 : 6 n-3 (DHA) were primarily esterified at the sn-2 position. In breast milk, major FAs (16 : 0, 18 : 1 n-9, LA, and ALA) and the ratio of PUFAs (LA/ALA and n-6/n-3) were obviously influenced by maternal edible oils. Breast milk from mothers consuming rapeseed oil had the lowest LA (∼19%) and the highest ALA (∼1.9%). The MUFAs, especially 18 : 1 n-9, in breast milk from mothers consuming high oleic acid oils were significantly higher than those in breast milk from mothers consuming other types of edible oils. These results provide a potential nutritional strategy for better breastfeeding by specifically adjusting maternal edible oils despite other fat sources being part of the diet of lactating women.