Vitamin A

Vitamin A is an essential fat-soluble vitamin that plays a crucial role in various physiological processes, including vision, immune function, reproduction, and cellular growth and differentiation. It exists in several forms: * **Preformed Vitamin A (retinoids):** Found in animal products like meat, dairy, and fish. The most common form is retinol, which can be converted to retinal and retinoic acid in the body. * **Provitamin A carotenoids:** Found in plant-based foods, such as fruits and vegetables. Beta-carotene is the most well-known provitamin A carotenoid, which the body can convert into retinol. Retinol is stored in the liver and transported throughout the body as needed. Due to its fat-soluble nature, excessive intake can lead to accumulation and potential toxicity, particularly with preformed vitamin A. The body's ability to convert provitamin A carotenoids into vitamin A is regulated, making toxicity from plant-based sources less likely (NIH ODS).