Mary Calvagna, MS
Vitamin A, also called retinol, is a fat-soluble vitamin. Our bodies store fat-soluble vitamins in the liver and fatty tissues. The active form of vitamin A is found in animal tissue. Red, orange, and dark green vegetables and fruits contain precursor forms of vitamin A called carotenoids. Our bodies can convert some of these carotenoids into vitamin A.
Here are some of vitamin A's functions:
The recommended daily dietary allowance for vitamin A is measured in micrograms (mcg) of Retinol Activity Equivalents (RAE).
Vitamin A deficiency is rare in the US, but it is common in developing countries. Here are some of the symptoms:
As a fat-soluble vitamin, vitamin A is stored in the body and not excreted in the urine like most water-soluble vitamins. Therefore, it is possible for vitamin A to accumulate in the body and reach toxic levels. For adults, the tolerable upper intake level (UL) for vitamin A from dietary sources and supplements combined is 3,000 RAE daily. It is less in children. Symptoms of toxicity include the following:
Too much vitamin A can cause severe birth defects. Pregnant women, and those who may become pregnant, should not take too much vitamin A from dietary sources and supplements.
The following foods contain carotenoids, which the body converts into vitamin A.
Populations at risk for vitamin A deficiency
The following populations may be at risk for vitamin A deficiency and may require a supplement:
Here are some tips to help increase your intake of vitamin A:
Academy of Nutrition and Dietetics
American Society for Nutrition
Dietitians of Canada
Health Canada Food and Nutrition
Dietary Supplement Fact Sheet: Vitamin A. Office of Dietary Supplements website. Available at:
http://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/. Updated July 25, 2012. Accessed February 7, 2013.
Fairfield KM, Fletcher RH. Vitamins for chronic disease prevention in adults: scientific review.
Vitamin A deficiency. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what. Updated November 22, 2011. Accessed February 7, 2013.
Vitamin A overdose. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what. Updated June 22, 2010. Accessed February 7, 2013.
Last reviewed February 2013 by Brian Randall, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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