Fatty acid composition of human milk during the 1st month after term and preterm delivery

The fatty acid composition of human breast milk was determined longitudinally after term and preterm delivery by high resolution gas liquid chromatography. Milk samples were obtained at days 5, 10, 20 and 30 after term (n = 38) or preterm (n = 19) delivery. The saturated fatty acids C10:0 and C12:0 and the polyunsaturates linoleic acid (C18:2 omega-6) and alpha-linolenic acid (C18:3 omega-3) increased significantly from day 5 to day 10, whereas arachidonic acid (C20:4 omega-6), total omega-6 long-chain polyunsaturates (LCP), docosahexaenoic acid (C22:6 omega 3) and total omega-3 LCP decreased significantly. Term and preterm milk did not differ in percentage content of linoleic acid, alpha-linolenic acid and LCP at any time point. Preterm milk contained significantly more medium and intermediate chain fatty acids (C10:0, C12:0 and C14:0) than term milk on days 5 (12.28 vs 9.78%; P > 0.05), 10 (16.25 vs 12.62%; P > 0.05) and 20 (17.29 vs 13.47%; P > 0.005).

The milk of mothers of preterm infants is not better suited to meet the high LCP requirements of their infants during the first weeks after birth. The slightly higher proportion of medium and intermediate chain fatty acids in preterm milk during the 1st month after birth might be advantageous for the fat and calcium absorption of preterm infants.