Simplified and rapid methods for the determination of protein, fat and lactose in human milk and the energy intake by the breast-fed infant.

Triacylglycerides constitute the bulk of fat in human milk. By centrifuging the milk a layer of fat is obtained, the cream, the fraction of which correlates very well with the total triacylglyceride concentration. It is determined in analogy to the haematocrit and is called galactocrit). Protein is determined with the biuret method in defatted milk. The interference due to lactose in this assay is on average 2 g/l. Lactose is determined with an enzyme kit. The amount of macronutrients in milk determines the energy value. A protocol is proposed, which makes it possible to measure the quantity of human milk drunk by the infant and to calculate the daily energy intake.