Multi-omics analysis reveals alterations of breastmilk metabolites and proteins in Hong Kong lactating mothers

The nutritional contents of breastmilk (BM) directly participate in neonatal metabolism via breastfeeding. Currently, there is limited research on BM metabolites and proteins compositions, and their alterations during the long lactation period in Hong Kong mothers. In this study, liquid chromatography-mass spectrometry-based metabolomics, lipidomics and proteomics studies were applied to compare the compositions in BM of Hong Kong lactating mothers at the 2nd, 6th, and 12th months after delivery. Distinct metabolomics and lipidomics signatures in 6th month versus 2nd month and 12th month versus 2nd month were observed, and a total of 19 differential metabolites and 105 lipids were identified. Metabolomics study showed the significant alterations in key pathways involved in biotin metabolism, amino acid, and fatty acid-associated metabolisms. Lipidomics analysis indicated the accumulation of triglyceride and ceramide during the lactation period. The remodeling of glycerophospholipids was also observed during 12-month period. Moreover, 28 differentially expressed proteins were identified and mainly associated with GO functions and KEGG pathways of ribosome and complement and coagulation cascades, which were validated by network analysis. Our research contributes to the understanding of the BM compositions and differences during the long lactation period in postpartum women of Hong Kong.