The effects of acidification on human milk's cellular and nutritional content

Fortification of human milk for preterm infants is necessary and a common newborn intensive care practice. Currently, acidified human milk as part of a human milk fortifier is being fed to preterm infants. However, there are little data on the acidification effects on mother's milk. The aim of this study is to determine the effects of acidification on human milk's cellular and nutritional composition.

One hundred milk samples were collected from eight mothers who had infants in the neonatal intensive care unit. All milk samples were frozen at 4 °C. The frozen samples were thawed and divided into two equal aliquots, control and acidified. The control milk sample had its pH determined while the other sample was acidified to pH 4.5. Each milk sample was examined for pH, white cells, total protein, creamatocrit, lipase activity and free fatty acids.

Mean pH of the human milk control was 6.8 ± 0.1 (M ± s.d.) with the acidified milk at 4.5 ± 0.1. Acidification caused a 76% decrease in white cells, a 56% decrease in lipase activity and a 14% decrease in the total protein but a 36% increase in the creamatocrit.

Acidification of human milk causes significant changes of the milk's cellular and nutritional components that may not be beneficial to preterm infants.