Vitamin+A




 * __ What is Vitamin A? __**

Vitamin A is a fat soluble vitamin.


 * __ Name __**** : **

The IUPAC name of Vitamin A is [|3,7-dimethyl-9-(2,6,6-trimethylcyclohexen-1-yl)nona-2,4,6,8-tetraen-1-ol] and its chemical formula is C20H30O.


 * __ Structure __**** : **

Figure A

Figure B

Figure A is a skeletal formula representation of vitamin A and Figure B is a space-filling representation of vitamin A.


 * __ How Vitamin A is Made __**** : **

Vitamin A is usually found to occur naturally in food products produced from animals. It is also possible to make vitamin A from compounds, called beta-carotene, that are derived from plants. Beta-carotene is a phytonutrient found in both vegetables and fruits and the compound is present in varying amounts. This compound is a form of pre-vitamin A and it can be easily converted to vitamin in the body. Vegetable and fruit based food sources that are coloured brightly in colours such as orange, yellow, dark green and red contain a greater amount of beta-carotene. Eggs, meat, milk, cheese, cream, liver, kidney, cod, and halibut fish oil are some main food products from animal based sources that contain vitamin A. Plant food sources that contain beta-carotene include sweet potatoes, pumpkins, carrots, spinach, winter squashes, apricots, broccoli and cantaloupe.




 * __ How Vitamin A Affects Us __**

Vitamin A is a part of two main functions within the body. Vitamin A affects vision ability and regulates tissue development ability within the body. An active form of vitamin A is retinol and it is related to the light sensitivity components of the eye that allows for vision during the night and during dim-lit conditions. Retinoic acid is another form of vitamin A that regulates the development of different tissues within the body, such as skin cells, and the lining of both lungs and intestines. Vitamin A is also an important component during the embryological development in the sense that without vitamin A, the fertilized egg cannot develop into a fetus.




 * Vitamin A Deficiency **

Deficiency in vitamin A occurs when food diets lack both vitamin A and the pre-vitamin form of vitamin A. Vitamin A deficiency usually occurs in people who consume large amounts of alcohol and those with an inability to absorb fat in the intestine. When an insufficient amount of vitamin A is consumed, infectious disease and problematic vision can occur.


 * Too much Vitamin A **

After consuming large doses of vitamin A, sickness can follow and birth defects might occur as well. Vitamin A poisoning is common when an adult consumes several hundred thousand IU of vitamin A or those that consume more than 25,000 IU of vitamin A each day. When infants take smaller doses of vitamin A or vitamin A-containing products, such as retinol, sickness can follow. Consuming large amounts of beta-carotene can turn the skin to a colour of yellow or orange and once the increase amount of beta-carotene being taken is reduced, the skin returns back to a normal colouration.

(0-13 years) || Male (14 years & up) || Female (14 years & up) || Pregnancy (14-15 years) || Lactation (14-50 years) ||
 * Recommended Dietary Allowance of Vitamin A**
 * Infants and Children
 * Infants and Children
 * 300-600 µg || 900 µg || 700 µg || 750-770 µg || 1200-1300 µg ||
 * __ Interesting Facts About Vitamin A __**

Although vitamin A can be found mainly in food products of animals, several animal types that live in polar environments have vitamin A that is poisonous for humans. This toxic vitamin A is found in the livers of these animals. For example, if the liver of a polar bear was eaten, there would be an adequate amount of vitamin A intoxicate and lead to death for a person.



Deficiency of vitamin A occurs when sufficient amounts of either vitamin A or beta-carotene are consumed. Night blindness is one of the first symptoms of vitamin A deficiency when there is a shortage of vitamin A within the body. Ultimately, when vitamin A is deficient within the body for a long period of time, blindness can become permanent and irreversible.

"Recommended Daily Allowances :: RDA Chart | RDA Table." //Guide to Health Supplements & Nutritional Healing//. Web. 04 June 2010. "Vitamin A, CAS Number: 68-26-8." //Chemindustry//. Web. 03 June 2010. . "Vitamin A Deficiency." //Encyclopedia - Online Dictionary | Encyclopedia.com//. Web. 04 June 2010. . "Vitamin A Interesting Facts." //NutrientFacts.com//. Web. 03 June 2010. . "Vitamin A: MedlinePlus Medical Encyclopedia." //National Library of Medicine - National Institutes of Health//. Web. 03 June 2010. . "Vitamin A." //Wikipedia, the Free Encyclopedia//. Web. 03 June 2010. . "Vitamin A." Web 04 June 2010. . “Vitamin A.” Web 04 June 2010. . "Vitamin A." Web 04 June 2010. . “Vitamin A.” Web 04 June 2010 . "Vitamin A." Web 04 June 2010 . "What You Need to Know about Vitamin A." //Eat Right Ontario//. Web. 03 June 2010. .
 * __ Sources __**** : **

Rebecca Hu Block D