Vitamin A is a general term encompassing various fat-soluble substances such as retinol, retinyl palmitate, and beta-carotene. Its various metabolites are essential for vision, cellular differentiation, epithelial barrier function, and immune function. Vitamin A is obtained through the diet in two forms. Preformed vitamin A (retinol and retinyl ester) is derived from animal sources such as meat, dairy products, and fish. Provitamin A (beta-carotenoid) is derived from colorful fruits and vegetables. Both ingested forms of vitamin A must be converted to retinal and retinoic acid after absorption to support biological processes. This activity outlines the indications, mechanism of action, methods of administration, important adverse effects, contraindications, toxicity, and monitoring, of vitamin A so providers can direct patient therapy in treatment or supplementation where it is indicated as part of the interprofessional team.
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