Dietary sialic acids: distribution, structure, and functions

Abstract

Sialic acids (Sias), a group of over 50 structurally distinct acidic saccharides on the surface of all vertebrate cells, are neuraminic acid derivatives. They serve as glycan chain terminators in extracellular glycolipids and glycoproteins. In particular, Sias have significant implications in cell-to-cell as well as host-to-pathogen interactions and participate in various biological processes, including neurodevelopment, neurodegeneration, fertilization, and tumor migration. However, Sia is also present in some of our daily diets, particularly in conjugated form (sialoglycans), such as those in edible bird’s nest, red meats, breast milk, bovine milk, and eggs. Among them, breast milk, especially colostrum, contains a high concentration of sialylated oligosaccharides. Numerous reviews have concentrated on the physiological function of Sia as a cellular component of the body and its relationship with the occurrence of diseases. However, the consumption of Sias through dietary sources exerts significant influence on human health, possibly by modulating the gut microbiota’s composition and metabolism. In this review, we summarize the distribution, structure, and biological function of particular Sia-rich diets, including human milk, bovine milk, red meat, and egg.

Keywords:

• Human milk oligosaccharide
• N-glycolylneuraminic acid
• sialic acid
• sialoglycan
• sialoglycoprotein

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Key Research and Development Program of China (2021YFC2101402) and the National First-Class Discipline Program of LigNational Key Research and Development Program of China (2021YFC2101402)ht Industry Technology and Engineering (LIT E2018-17).