vitamin A


vitamin A

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.

Variants of VITAMIN A

vitamin A also called retinol

This entry comes from Encyclopædia Britannica Concise.
For the full entry on vitamin A, visit Britannica.com.

Seen & Heard

What made you look up vitamin A? Please tell us what you were reading, watching or discussing that led you here.

Get Our Free Apps
Voice Search, Favorites,
Word of the Day, and More
Join Us on FB & Twitter
Get the Word of the Day and More