The lipid content and the fatty acid pattern in human colostrum, transitional and mature milk and in pasteurised cow's milk and in "Vorzugsmilch" (special untreated milk) were investigated. The analyses were done in pooled daily milk of 15--20 women to archieve representative mean values for human milk.
The lipid content amounted to 1.87 g/100 ml in human colostrum, 2.82 g/100 ml in transitional milk and 3.45 g/100 ml in mature human milk. The increase of lipid content during lactation is attributed to maturation of the milk and is not influenced by maternal diet. During maturation of human milk decreases the portion of the unsaturated fatty acids from 57 to 53~o, the portion of saturated fatty acids increases accordingly from 43 to 47%. The decrease of the unsaturated fatty acids is mainly due to the decrease of oleic acid while the portion of linoleic acid increases from 10.8 to 12.0%. In the same duration the linoleic acid portion of the energy content of human milk increases there with from 3.3 kc~l ~o in colostrnm to 5.6 kcal ~o in mature human milk.
Lipid content and fatty acid pattern of pasteurised cow's milk ~nd "Vorzugsmilch" were compared with the corresponding values in human milk.
The importance of the differences in lipid content and fatty acid pattern of human milk and cow's milk for the nutrition of healthy young infants is discussed.