Polyunsaturated fatty acid composition of human milk in France: changes during the course of lactation and regional differences.

Milk samples were collected 2-5, 15, 30, 60 and 90 days postpartum from 41 individual mothers recruited in three French cities in order to obtain a general view of the polyunsaturated fatty acid (PUFA) composition in France. Considering the overall results, linoleic acid (18:2 n-6) represented between 11.6% and 13% of total fatty acids in human milk. In contrast alpha-linolenic acid (18:3 n-3) accounted only for about 0.6%, and hence the 18:2 n-6 to 18:3 n-3 ratio was close to 20. Amounts of n-6 and n-3 long-chain PUFAs (LCPs) regularly decreased from postpartum days 2-5 (3.09%) to day 30 (1.67%), and then remained unchanged up to postpartum day 90; the n-6/n-3 LCP ratio ranged between 2.5 and 2. According to regional areas, there were significant differences (P < 0.05) only for colostrum contents of 18:3 n-3 and LCPs, the LCP ratio remaining unchanged. These data are discussed with regard to recent data on human milk fatty acid composition from Western countries and to the mechanisms involved in milk LCP balance.