The three main forms of vitamin A are retinol (as shown to the right), retinal and retinoic acid.  Sources of vitamin A can be found as retinol in milk, fortified margarine, butter, cheese, egg yolk, liver and fatty fish.  Bright orange and deep green vegetables eg. carrots and broccoli as well as milk and tomatoes  contain the vitamin A precursor beta carotene, a disease fighting antioxidant.