What is vitamin A?

Advertisement
Advertisement
Marjorie Nolan Cohn
Nutrition & Dietetics
Vitamin A is a fat-soluble vitamin. It also called retinol, mainly because it produces pigments in the eye's retina. The eye needs a specific metabolite of vitamin a, called retinal which is important for vision. Vitamin A is also important for healthy teeth, skeletal tissue, soft tissue, the skin, and mucous membranes.

Vitamin A comes from two main types of foods:
  • Retinol -- It is the form of vitamin A absorbed when eating animal foods, such as cod liver oil, butter, liver, eggs, cheese and milk.
  • Carotenes -- such as alpha-carotene, beta-carotene, gamma-carotene, and xanthophyll beta- cryptoxanthin. Carotene is an orange photosynthetic pigment crucial for plant photosynthesis. The orange colors of carrots, sweet potatoes and cantaloupe melons come from its carotene content. Lower carotene concentrations are what give the yellowish coloration to butter and milk-fat. Some omnivores have yellow-colored body fat, such as chickens and humans.
Vitamin A is actually a family of substances called retinoids that includes retinol, retinal, and retinoic acid. These are called preformed vitamin A because they are in a form that your body readily uses. Retinol is the most usable of the three forms and can be converted to both retinal and retinoic acid in your body.

Preformed vitamin A is found only in foods from animal sources, such as liver and eggs, and is added to all processed milk. Plant food sources do not contain preformed vitamin A, but some do contain provitamin A carotenoid, which can be converted to retinol in your body. Carotenoids are the yellow-red pigments that give carrots, butternut squash, and cantaloupe their vibrant, deep orange color.
Picture of cantaloupe

Vitamin A is a fat-soluble vitamin needed for the growth of cells and bone, reproduction, healthy eyes and skin, and the maintenance of healthy respiratory, intestinal, and urinary tracts. This vitamin occurs in foods such as dark green and yellow vegetables, milk, eggs, cheese, squash, carrots, and in fruits such as apricots and cantaloupe. Vitamin A is used as a supplement for treatment of vitamin A deficiency, and it can also be used for other purposes.

Continue Learning about Vitamin A

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.