Fatty acid composition of human breast milk. Changes during the first week after delivery

Breast milk was collected daily from 11 healthy Polish mothers during the first week after delivery. The method of Folch was found suitable for fat extraction from breast milk. The concentration of total fat and of triglycerides and the fatty acid composition of total fat were determined. The concentration of total fat was 2.4 g/100 ml on the second day after delivery and 4.4 g/100 ml on the seventh day. There was a similar rise in the triglyceride concentration. No relation was found between the concentration of total fat and the relative concentrations of fatty acids. The major fatty acids were 18:1 and 16:0, which comprised about 70 per cent of the fatty acids. The essential fatty acids comprised about 10 per cent of the total fatty acids. The fatty acid spectrum changed during the sampling period. The proportions of 10:0, 12:0, 14:0 and 16:1 increased, those of 16:0, 18:2, 20:0 and 22:0 were unchanged, and those of 18:0 and 20:4 decreased. Very long-chained polyunsaturated fatty acids, e.g. 22:6, were also present. All the polyenoic acids - except 18:2 showed the highest concentrations on the first day after delivery.