Maternal n-3 fatty acid supplementation has an immediate impact on the human milk fatty acid composition.

Background. Fatty acids are essential components in breast milk with mutable characteristics. The fatty acid profiles of breast milk varied with lactating women's intake of long-chain polyunsaturated fatty acids (LCPUFAs) including DHA, EPA, and ALA. Objective. This study aimed to investigate the correlation between dietary n-3 PUFA supplementation and the hourly variation of the fatty acid compositions in breast milk. Materials and methods. The fatty acid profiles were analyzed in 600 human milk samples from 8 hospitals in 8 different Chinese areas. Blood and breast milk samples were obtained from a group of seventy-five lactating mothers, all within 6 to 9 months postpartum. Each mother collected 8 dried milk samples (DMSs) within 2 days: half an hour before breakfast; 2 and 3 hours after breakfast every day; and 2 and 3 hours after lunch on day 1. One fingertip blood sample was collected 10 minutes before the breakfast on the first day. The mothers took supplements containing about 3 grams of n-3 PUFAs at 10 minutes before the breakfast on day 2. Results. (1) In breast milk, oleic acid (C18:1n9c, OA) was the most abundant fatty acid (35.55%) followed by C18:2n6c (linoleic acid, LA, 24.45%); (2) the breast milk DHA of the inland participants (0.26%) was lower than that from coastal participants (0.57%), but compensated with much higher ALA (inland 3.19% vs. coastal 2.21%), and thus provided higher total milk n-3 PUFAs (inland 3.88% vs. coastal 3.28%); (3) the breast milk EPA and DHA increased from the baseline (EPA 0.17% and DHA 0.44%) after supplementation in 2 hours (EPA 0.18% and DHA 0.44%) and 3 hours (EPA 0.19% and DHA 0.46%). Conclusions. Dietary supplementation of n-3 PUFAs had an immediate impact on the breast milk fatty acid composition. The concentration of ALA, LA and OA was strengthened in breast milk compared to that in maternal blood.