Abstract

Fat in human milk forms the main energy source for infants and is the most variable component in terms of concentration and composition. Knowledge on changes in human milk lipid composition and conformational state during a single breastfeed contributes to an in-depth understanding of lipid synthesis in the mammary gland. Therefore, the objective of this study was to evaluate the differences in fatty acid length, degree of unsaturation (lipid composition) and lipid phase (lipid conformational state) of milk released at different stages during a breastfeed (fore-, bulk- and hindmilk). A total of 30 samples from 10 lactating subjects were investigated using confocal Raman spectroscopy. No significant differences in lipid composition were observed between fore-, bulk- and hindmilk samples, which is consistent with literature. A new finding from this study is that the lipid conformational state in human fore-, bulk- and hindmilk was significantly different at room temperature. The lipid phase of foremilk was almost crystalline and the lipid phase of hindmilk was almost liquid. Based on this observation, we hypothesize that lipid synthesis in the mammary gland changes during a single breastfeed.

© 2021 The Author(s)