Description
Vitamin A is a group of unsaturated nutritional organic compounds that includes retinol, retinal, retinoic acid, and several pro-vitamin A carotenoids. This vitamin has multiple functions: it is important for growth and development, for the maintenance of the immune system, and for good vision. Vitamin A needed by the retina of the eye in the form of a specific metabolite, the light-absorbing molecule retinal that is necessary for both low-light (scotopic vision) and color vision. Vitamin A also functions in a very different role as an irreversibly oxidized form of retinol known as retinoic acid, which is an important hormone-like growth factor for epithelial and other cells