Vitamin A
What is vitamin A?
Vitamin A was the first so-called "fat-soluble" vitamin to be recognised in 1913.
This vitamin is also known as retinol (also called retinal or retinoic acid), a word much favoured by manufacturers of skin preparations that aim to retard the ageing process.
It also has the chemical names retinol palmitate and retinol acetate. "Vitamin A" is actually the collective name for compounds with the biological activity of retinol, which was originally isolated from the retina in the eye. Vitamin A is absorbed by the body in the form of retinol.
Plant pigments called carotenoids, converted to retinol by the body through the process of metabolism, are found in various vegetables and fruits. These compounds are also referred to as "provitamins A" as they are precursors of the useful form of the vitamin. Not all of the carotenoid varieties have significant provitamin A activity.
The most active form of these provitamins is beta-carotene. This precursor has been the subject of many a research study during the last couple of years, as it is believed to have strong anti-cancer properties.
What does vitamin A do for you?
Your body needs vitamin A to produce rhodopsin, the pigment that helps you to see in the dark.It also helps the mucosal linings of the mouth, digestive, urogenital and respiratory systems to stay moist, to prevent intrusion of foreign organisms and toxins, and to heal after infection or inflammation, as well as ensuring the development of strong bones, a functional reproductive system and healthy skin.
The vitamin plays an important role in reproduction and also helps your immune system, enabling you to ward off bacterial, parasitic or viral infections. For this reason, vitamin A supplements help children to recover more quickly from measles, and lower the risk of developing serious complications from measles.
Vitamin A is also a potent antioxidant. The word "antioxidant" refers to a substance that can inhibit the activity of free radicals - unusually reactive, strongly oxidising atoms capable of causing a wide range of biological damage in the body, of which the most pronounced is cancer.
