Retinol (Vitamin A)

 

Vitamin A has the distinction of being the first fat-soluble vitamin to be recognized. Today, after almost a century of research, Vitamin A and its plant-derived cousin, beta-carotene, are still very much a focus of research. Vitamin A is one of the most versatile vitamins, with roles in such diverse functions as vision, immune defenses, maintenance of body linings and skin, bone and body growth, normal cell development, and reproduction. In addition to being crucial for eye health, Vitamin A is needed by all epithelial tissue; that is the tissue which has an external surface, and an internal lining; such as the nose, eyes, mouth, genitalia, and so on. The skin and all of the protective linings of these areas serve as barriers to infection by bacteria and to damage from other sources. Vitamin A works at the genetic level to promote the process of cell differentiation, which allows each type of cell to mature so that it is capable of performing a particular function to help bar infections from taking hold. Another emerging area of research concerns the roles of Vitamin A in the regulation of the genes that produce proteins involved in immunity. Without sufficient Vitamin A, these complex genetic interactions produce an altered response to infection that weakens the body's defenses against disease. Vitamin A also assists in bone growth. Normal children's bones grow longer, and the children grow taller, by remodeling each old bone into a new bigger version. To do so, the body dismantles the old bone structures and replaces them with new, larger bone parts. Growth cannot take place just by adding on to the original small bone; Vitamin A is needed in the crucial dismantling steps. In some children, failure to grow is one of the first signs of Vitamin A deficiency