Vitamin A
Topics covered:
- What is vitamin A?
- What does vitamin A do for us?
- What types of foods contain vitamin A?
- What is the Recommended Daily Allowance (RDA)?
- Are there health risks associated with vitamin A?
- How does our body convert precursor vitamin A (beta-carotene) into retinal? (coming soon)
- References
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Vitamin A is a fat-soluble essential micronutrient. Vitamin A can be derived from animal-based compounds called retinoids, or plant-based compounds called carotenoids.
Retinoids: retinol, retinoic acid
Carotenoids: alpha-carotene, beta-carotene, beta-cryptoxanthin, and gamma-carotene
What does vitamin A do for us?
Vitamin A is essential for vision, cell functions, our immune system, bone development, and skin maintenance (epithelial tissue). It can also enhance a man’s sperm count and act as an antioxidant by neutrilizing free radicals. As noted above, Vitamin A is either derived from a retinoid or carotenoid:
- Retinoids are animal based chemical compounds that consist of either retinol or retinoic acid. Once consumed, retinol can be converted to retinal. Retinal is essential for vision because it produces pigments in the retina of the eye. Pigments are needed for seeing colors and at nighttime. Retinoic acid, on the other hand, promotes skin and bone growth. Retinoids can be found in milk, liver, and eggs.
- Carotenoids are plant based compounds (phytonutrients) that can act as antioxidants or can be converted to retinol (see Retinoids). Carotenoids can also help boost our immune system and enhance the male’s sperm count. Caroteniods can be found in fruits like cantaloupe, apricots, and pink grapefruit, as well as vegetables like spinach, broccoli, squash, pumpkins, and carrots; rule of thumb, the more intense the fruit or vegetable color, the more carotene it has.
What types of foods contain vitamin A?
Vitamin A can naturally be found in spinach, carrots, cantaloupe, and potatoes, as well as milk, cod, liver and eggs.
What is the Recommended Dietary Allowance (RDA)?
Ages 1-3 years: 300 mcg – 600 mcg
Ages 4-8 years: 400 mcg – 900 mcg
Ages 9-13 years: 600 mcg – 1,700 mcg
Ages 14+ years (females)*: 700 mcg
Ages 14+ years (males)*: 900 mcg
*If you are pregnant or breast feeding, consult with a dietitian for your RDA.
Are there health risks associated with vitamin A?
Vitamin A deficiency leads to impaired vision (especially night blindness), slowed bone development, and a weaker immune system
- Boyle, Marie A., and Sara Long. Personal Nutrition, Seventh Edition California, Wadsworth College Learning, 2010.
- “Fortify your knowledge about Vitamins.” U.S. Food and Drug Administration. February 21, 2009. Retrieved May 10, 2011 <http://www.fda.gov>
- “Vitamin A.” U.S. National Library of Medicine. March 19, 2011. Retrieved April 15, 2011 <http://www.nlm.nih.gov/medlineplus>
- “Vitamin A and Beta Carotene.” American Cancer Society. February 23, 2010. Retrieved April 15, 2011. <http://www.cancer.org>
- “Vitamin A” Harvard School of Public Health. 2011. April 15, 2011 <http://www.hsph.harvard.edu/nutritionsource/index.html>
- “Vitamin A.” Health Supplements Nutritional Guide. 2008. Retrieved April 15, 2011 <http://www.healthsupplementsnutritionalguide.com>
- “Vitamin A and Carotenoids.” Office of Dietary Supplements. 2011. Retrieved May 01, 2011 <http://ods.od.nih.gov>
- Griffin, Morgan R. “Vitamin A (Retinoid).” WebMD. David C Leopold, MD. December 8, 2010. Retrieved April 21, 2011 <http://www.WebMD.com>
Disclaimer
Reasonable care has been taken in preparing this document, and the information provided herein is believed to be accurate. However, this information is not intended to constitute an “authoritative statement” under Food and Drug Administration rules and regulations.
General Safety Advisory
This information is not intended to be a substitute for professional medical advice. It is important to seek the advice of a physician about any medical condition or symptom. It is also important to seek the advice of a physician, registered dietitian, pharmacist, or other qualified health professional about the appropriateness of taking dietary supplements and their potential interactions with medications.