Vitamin A: Key Facts and Health Benefits | Nutrition & Dieting slideshows | Well Being center

Why do people take vitamin A?

Vitamin A supplements are given to those patients that present a dietary deficiency of this compound. It is mainly used in children, pregnant women and elderly people of developing countries, where the diet does not fulfill the daily requirements of Vitamin A and other nutrients. Vitamin A is also present in face and body creams, as it helps to keep it nice and moist, and it helps in the healing process of wounds and burns. Vitamin A supplements can be found combined with other vitamins, as in multivitamin supplements, or alone, but its use should be monitored, as it can be toxic in high doses.

Sources & Links

Important notification about information and brand names used in this slideshow!
Photo courtesy of SOCIALisBETTER by Flickr : www.flickr.com/photos/27620885@N02/2603600928/
ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/#en1
http://www.cancer.org/treatment/treatmentsandsideeffects/complementaryandalternativemedicine/herbsvitaminsandminerals/vitamin-a-and-beta-carotene
SHILS, M. E. & SHIKE, M. 2006. Modern nutrition in health and disease, Philadelphia, Lippincott Williams & Wilkins.

Vitamin A: Retinoids and carotenoids.

Vitamin A refers to a group of fat-soluble compounds, known as retinoids and carotenoids, that are a basic component of our diet. Vitamin A participates in several body processes, including growth and development, reproduction, bone maintenance, vision and the immune response. In recent years, scientists have also shown that it has a role in learning and memory processes, which are controlled by the central nervous system. Because of this, its deficiency can cause severe health problems, from night blindness and skin alterations, to complete blindness and death. Vitamin A deficiency is mainly seen in children and pregnant women of developing countries.

Sources & Links

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Photo courtesy of Colin Dunn by Flickr : www.flickr.com/photos/colindunn/4398689374/
www.healthdiaries.com/eatthis/7-health-benefits-of-vitamin-a.html
http://www.organicfacts.net/health-benefits/vitamins/health-benefits-of-vitamin-a-or-retinol.html
http://www.webmd.com/vitamins-and-supplements/lifestyle-guide-11/supplement-guide-vitamin-a
http://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/#en1

How much vitamin A should you take?

The amount of Vitamin A that you should take depends on your age and sex. Children of 2 years old or younger and adults of 70 yo or older have major Vitamin A requirements than the rest of the population; also, men normally need a higher intake of this vitamin than women. During pregnancy, Vitamin A requirements increase as well, as many other nutrients do. A healthy balanced diet that includes meat, fish, dairy products, fruits and vegetables should be enough to fulfill Vitamin A requirements in both children and adults. However, if a nutrient deficiency is identified, Vitamin A supplements can be used to avoid health problems.

Sources & Links

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Photo courtesy of sotheavy by Flickr : www.flickr.com/photos/teeves/3677026849/
www.niams.nih.gov/Health_Info/Bone/Bone_Health/Nutrition/vitamin_a.asp
http://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/#en1

Deficiency symptoms of vitamin A

Vitamin A deficiency affects mainly children, pregnant women and elders living in developing countries, where the nutritional conditions are far from being optimal. The main symptoms that arise due to lack of vitamin A are related to alterations in vision, such as night blindness and alterations in the cornea. A lack of Vitamin A can also cause rashes, dry hair and skin, broken fingernails and weak bones and teeth. Because Vitamin A is required for the immune system to function properly, its deficiency diminishes the efficacy of the immune response, making people vulnerable to bacterial and viral infections.

Sources & Links

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Photo courtesy of Community Eye Health by Flickr : www.flickr.com/photos/communityeyehealth/5492473278/
www.merckmanuals.com/professional/nutritional_disorders/vitamin_deficiency_dependency_and_toxicity/vitamin_a.html
http://www.patient.co.uk/doctor/Vitamin-A-Deficiency.htm

Vitamin A improves immunity

Our immune system requires Vitamin A to fight against infections, especially in the intestine. It helps in the production of specialized cells that are in charge of stopping bacteria and viruses from getting into our system by favoring the response to the site of infection and maintaining a protective intestinal environment. Vitamin A also possess anti-inflammatory and anti-oxidant properties. The first one helps to modulate the immune response and avoid tissue damage when the immune system is fighting against a pathogen. The anti-oxidant properties, on the other hand, are useful in persons with atherosclerosis and heart disease, as they prevent and protect from damaged caused by free radicals.

Sources & Links

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Photo courtesy of Mike Baird by Flickr : www.flickr.com/photos/mikebaird/3627042669/
www.nlm.nih.gov/medlineplus/antioxidants.html
MORA, J. R., IWATA, M. & VON ANDRIAN, U. H. 2008. Vitamin effects on the immune system: vitamins A and D take centre stage. Nat Rev Immunol, 8, 685-98.

Important sources of vitamin A

Vitamin A can be found as retinol in meat, eggs, dairy products, like milk and cheese, fish and fish oils. The main animal source of vitamin A is the liver, because, even in humans, vitamin A and its precursors are stored in the liver. Carotenoids, mainly beta carotenoid, are pro-vitamin A compounds that are transformed into vitamin A once they are in our system. These are found in vegetables and fruits like carrots, squash, green leaves, broccoli, apricots and mango. Even though there are vitamin A supplements available, a healthy person should be able to acquire vitamin A from these sources, unless there is a problem of poor absorption that is not allowing vitamin A to reach the organs.

Sources & Links

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Photo courtesy of essie by Flickr : www.flickr.com/photos/64148767@N00/6867298356/
www.cancer.org/treatment/treatmentsandsideeffects/complementaryandalternativemedicine/herbsvitaminsandminerals/vitamin-a-and-beta-carotene
http://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/#en1

Vitamin A can aid in improved vision

Retinoids and carotenoids are absorbed in our intestine and transported to our organs in the form of Vitamin A. Vitamin A is a chromophore, a colored substance that absorbs and transmits light, and is needed for vision. People lacking Vitamin A tend to develop night blindness, so it is important to fulfill our nutritional requirements of Vitamin A in order to maintain a good vision. It is known that eating carrots can help in the maintenance of a good your vision, and it does, however, increasing the ingest of food rich in Vitamin A will not make a huge difference. A normal diet containing both animal and plant sources of Vitamin A should be enough to prevent any alterations in our vision.

Sources & Links

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Photo courtesy of Matt-Richards by Flickr : www.flickr.com/photos/45511562@N04/4978455939/
www.dukehealth.org/health_library/health_articles/myth_or_fact_eating_carrots_improves_eyesight
VON LINTIG, J. 2012. Metabolism of carotenoids and retinoids related to vision. J Biol Chem, 287, 1627-34.

For stronger bones and teeth

Vitamin A is also needed to maintain healthy bones and teeth, however, scientists have seen that an excessive intake of this vitamin is not beneficial at all. Because it promotes the formation of osteoclasts, the cells that break down bone tissue, it can cause bone fractures and may be related to the development of osteoporosis. It is also possible that vitamin A interacts with vitamin D, making it not available for normal bone production. The two main vitamin A forms, retinol and beta carotenoid, are contained in many supplements and preparations used as skin treatments, but is the retinol the one that has been linked to toxicity and bone damage.

Sources & Links

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Photo courtesy of indrarado by Flickr : www.flickr.com/photos/indrarado/5537718519/
ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/#h3
http://www.niams.nih.gov/Health_Info/Bone/Bone_Health/Nutrition/vitamin_a.asp

Prevents acne and keeps the skin soft and supple

Vitamin A helps in the maintenance of the outer skin layer and keeps the skin smooth and healthy. It also participates in the protection of the mucosal tissue present in the gastrointestinal tract. Because of this properties, vitamin A in the form of retinol is is used for the treatment of acne, psoriasis and eczema, as well as burns, scars and warts. Anti- aging creams, for example, contain retinoids, because vitamin A can help in the process of avoiding skin aging and the formation of wrinkles. Medications that contain vitamin A should be prescribed by a physician, because they require supervision.

Sources & Links

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Photo courtesy of Don LaVange by Flickr : www.flickr.com/photos/wickenden/2533952752/
umm.edu/health/medical/altmed/supplement/vitamin-a-retinol

Other health benefits of Vitamin A

In recent years, based on the role that vitamin A plays in cell growth and proliferation, scientists have studied Vitamin A as a potential compound for the treatment of skin, breast, liver, colon, prostate, and other types of cancer; however, there is still no evidence that can fully support this idea. Synthetic vitamin A is nowadays used for the treatment of leukemia, retinitis pigmentosa and skin diseases. Also, vitamin A has been identified as a very important compound for the central nervous system activities, including learning and memory, and its antioxidant properties makes it a compound able to prevent oxidative damage to any tissue.