Sust. MASC. Vitamin A, also known as axeroftol ( alcohol against dryness ) anti-infection factor and antixeroftálmico ( against the dryness of the 41 eyes;. Oily hydrocarbon ( oily ) insoluble in water and soluble in oils and fats ( fat-soluble ) formula C20H30O. Their precursors or provitamins-A are the carotenes: yellowish Orange pigments which in most plants coexist with the chlorophyll. The carotenes denomination comes from the taxonomic carrot species name: «Daucus carotta». Esterified by fatty acids, vitamin A exists in milk, butter and various bodies - mainly in the liver of animals whose foods are rich in carotenes. Likewise obtained from the liver of cod and hypoglossal ( the family of the sole ). Retinol comes from the Latin «retina»: redecita ( ocular membrane with abundant nerve fibers that radiate from the optic nerve ) and the "ol" suffix: own in organic chemistry of compounds containing hydroxyl radical: OH, of alcohols.