The term Vitamin A actually refers to a broad group of important compounds. As with most vitamins, Vitamin A cannot be made directly by the body it can be obtained only through food and supplements. Preformed retinoids come to us from animals, particularly in the form of liver, kidney, egg and other dairy products. We absorb these retinoids as retinol, which is later converted into retinal and retinoic acid in the body. These retinoids are called preformed because we take them in ready to go we don't have to manufacture the Vitamin A ourselves. Pro-vitamin carotenoids come to us from plants although plants do not provide Vitamin A directly. Instead, they contain pro-Vitamin A carotenoids which are then transformed into Vitamin A. Carotenoids are beneficial antioxidants. Of all the carotenoids, beta-carotene is the most common, has the highest level of Vitamin A activity, and is the easiest to convert into retinol.
There are two main forms of Vitamin A:
Natural retinoids are present in all living organisms either as preformed Vitamin A or as carotenoids. They are important to a large number of biological processes such as bone growth, vision, and immune defense.
Vitamin A deficiency is rare in the United States and other developed nations, but it remains a concern in many developing countries, particularly those where malnutrition is common. A prolonged deficiency of Vitamin A can lead to blindness as well as many other complications.
- Vitamin A is the general name for substances that include retinol, retinal and the carotenoids.
- Vitamin A is essential for new cell growth and healthy tissue.
- Vitamin A is essential for good vision.
- Retinol from Vitamin A is used to form rhodopsin, an important part of the retina that provides information about color and visual images.
- Vitamin A contributes to immune health by supporting the integrity of the respiratory, gastrointestinal and urinary tracts.
- Vitamin A is believed to help regulate important immune response elements, including immunoglobulin production, lymphocyte and natural killer cell function, and interleukin production.
- Vitamin A is essential for healthy skin and hair.
- Vitamin A supports antioxidant health.
- Vitamin A helps fight cell-damaging free radicals in the body.
- Free radicals can contribute to oxidative stress, which in turn may contribute to the premature aging of cells.
- As an antioxidant, Beta-Carotene is a natural way to deal with the stresses of everyday living.
- Vision: The role of Vitamin A in promoting good vision is largely related to the retina the thin, sensitive membrane lining the back of the eye which receives the image from the lens. One form of Vitamin A is a protein called 11-cis retinol which absorbs light and begins the chemical reaction which allows the eye to see.
This process called isomerization transmits a signal along the optic nerve to the visual center of the brain. Vitamin A also contains a retinoid which inhibits macular degeneration (the loss of vision in the center of your view), and other types of damage to the retina.
- Immune response: Vitamin A helps support our immune system and is also believed to help regulate important immune response elements.
- Skin: Vitamin A encourages healthy skin while also supporting hair health.
Vitamin A is found naturally in many foods, especially animal livers, fish oils, and green/yellow fruits and vegetables.
| || |
| || |
| || |
| || |
| || |
| || |
| || |
The structure function claims made on this website have not been evaluated by the Food and Drug Administration. These dietary supplement products are not intended to diagnose, treat, cure, or prevent any disease.