Role of breast milk lipid composition in postnatal brain development.

Lipids in the brain play a crucial role as structural and signaling molecules, accounting for approximately 60% of the brain’s dry weight. Several lipid classes exhibit concentration profile differences between humans and other species, including closely related primates, with the most pronounced differences occurring during the first year of life. The long-chain polyunsaturated fatty acids (LC-PUFAs) that accumulate specifically in the brain are largely derived from nutrition – primarily breast milk during infancy. In this study, we analyze 837 milk samples from seven mammalian species and 194 brain samples from four mammalian species across two brain regions using liquid chromatography coupled with mass spectrometry (LC-MS). We show that differences in brain fatty acid composition are reflected in milk fatty acid composition and identify human-specific lipids present in both breast milk and the brain. Our findings highlight the influence of milk composition on brain development and suggest its potential role in shaping the unique cognitive features of the human brain.