*Vitamin A is one of the essential trace elements for the human body. Vitamin A can promote the synthesis of immune proteins, maintain the normal metabolism of epithelial cells, and promote the synthesis of immunoglobulins. This function is mainly because it participates in the synthesis of glycoproteins. In maintaining or regulating normal immune functions, it will plays a key role. Vitamin A is an essential nutrient for the human body. Vitamin A can maintain the health of the surface of tissues or organs, and can restore rough skin to normal.