More than 70% of proteins in breast milk are glycosylated, and glycosylation enzymes cleave specific structures that connect proteins to polysaccharides. However, the human digestive system does not secrete glycosylation enzymes. Therefore, glycosylated proteins are more likely to retain their activity and exert their functions in the digestive system compared with non-glycosylated proteins. This article introduces the types, composition and content of glycoproteins in breast milk, analyzes the mechanism underlying their biological functions, and reviews recent progress in glycoproteomics. We expect that this review will provide a reference for research on the biological functions of glycoproteins in breast milk
