Definition of vitamin a in English English dictionary
Any of several closely related fat-soluble vitamins that are essential for normal vision; retinol
A fat-soluble vitamin or a mixture of vitamins, especially vitamin A, occurring principally in fish-liver oils, milk, and some yellow and dark green vegetables, and functioning in normal cell growth and development. Its deficiency causes hardening and roughening of the skin, night blindness, and degeneration of mucous membranes. Also called retinol. also called retinol Fat-soluble alcohol, most abundant in fatty fish and especially in fish-liver oils. It is not found in plants, but many vegetables and fruits contain beta-carotene (see carotene), which is readily converted in the body to vitamin A. It functions directly in vision, especially night vision. A derivative, retinaldehyde, is a component of the visual pigments, including rhodopsin, in the retina. Humans require vitamin A in very small amounts. Unlike carotenes, it is toxic in large amounts and is readily destroyed by exposure to heat, light, or air
{i} retinol, yellow fat-soluble terpene alcohol found in liver oil and carotenoids (essential for growth and good vision)
any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyes