Milk Letdown and the Concentration of Fat in Breast Milk

Abstract

Fat contributes 54% of the gross energy content of human milk1- but is by far the most variable component of breast milk. Although the concentration of milk fat has been reported to vary over the course of 24 h 2,3,4,5 by far the largest changes in the concentration of fat in milk occur between the beginning and the end of a single breast feed3 Indeed, visible compositional changes occur, with fore milk at the beginning of a breast feed usually appearing a watery bluish-white and hind milk at the end of a breast feed usually appearing white and creamy.