Vitamin A can maintain skin and mucous membrane integrity and promote immune function

Maintaining skin and mucous membrane integrity: Vitamin A is a coenzyme that regulates glycoprotein synthesis, which stabilizes the cell membrane of epithelial cells and maintains the morphological integrity and function of epithelial cells. This effect of vitamin A on tissue function and integrity is achieved by mediating the exchange of information between adjacent cells. Vitamin A deficiency causes epithelial tissue to dry out, and normal columnar epithelial cells transform into horny squamous cells, leading to keratinization of the cells. Epithelial cells of various tissues of the body are affected, but the earliest involvement is the conjunctival, corneal and lacrimal gland epithelial cells. The reduction of lacrimal gland secretion leads to dry eye, conjunctiva or cornea dry, softened and even perforated. Epithelial cells such as skin hair follicles, sebaceous glands, sweat glands, tongue buds, respiratory and intestinal salvage membranes, urinary and reproductive sacs are affected, resulting in impaired clinical manifestations and impaired mucosal barrier function.
Maintaining and promoting immune function: Retinoids are essential for maintaining immune function, which relies on cell differentiation and proliferation triggered by immune stimulation. The regulation of target genes by nuclear receptors by retinoic acid can improve cellular immune function, promote the production of antibodies by immune cells, and promote the production of certain lymphokines by T lymphocytes. Retinoic acid is extremely important for maintaining a sufficient level of natural killer cells in circulating blood, which has antiviral and antitumor activity. Retinoic acid has been shown to increase the phagocytic activity of murine macrophages and increase the production of interleukin-1 and other cytokines, which are mediators of inflammatory responses and activators of T and B lymphocyte production. In addition, retinol is also required for the growth, differentiation and activation of B lymphocytes. When vitamin A is deficient, the expression of retinoic acid receptor in immune cells is decreased, which affects the immune function of the body. Children with vitamin A deficiency and marginal deficiencies have an increased risk of infectious disease and increased mortality.