Akademik

A substance that can be converted into a vitamin; e.g., β-carotene.

- p. A trivial name for carotenoids exhibiting qualitatively the biologic activity of β-carotene, i.e., vitamin A precursors (α-, β-, and γ-carotene and cryptoxanthin); contained in fish liver oils, spinach, carrots, egg yolk, milk products, and other green leaf or yellow vegetables and fruits.

- p. D₂ any substance that can give rise to ergocalciferol (vitamin D₂); e.g., ergosterol.

- p. D₃ SYN: 7-dehydrocholesterol.

pro·vi·ta·min (')prō-'vīt-ə-mən n a precursor of a vitamin convertible into the vitamin in an organism <ergosterol is a \provitamin of vitamin D>

a substance that is not itself a vitamin but can be converted to a vitamin in the body. An example is b-carotene, which can be converted into vitamin A.