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:
American Society for Nutrition
Eat Right—Academy of Nutrition and Dietetics
Dietitians of Canada
Vitamin A. Oregon State University Linus Pauling Institute website. Available at: http://lpi.oregonstate.edu/mic/vitamins/vitamin-A. Updated February 2015. Accessed February 24, 2016.
Fairfield KM, Fletcher RH. Vitamins for chronic disease prevention in adults: Scientific review.
Vitamin A. Office of Dietary Supplements website. Available at:
https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional. Updated August 31, 2016. Accessed February 24, 2017.
Vitamin A deficiency. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T115371/Vitamin-A-deficiency. Updated February 16, 2017. Accessed February 24, 2017.
Vitamin A Toxicology. EBSCO DynaMed website. Available at: http://www.dynamed.com/topics/dmp~AN~T526141/Vitamin-A#Toxicology. Updated February 6, 2017. Accessed February 24, 2017.
Last reviewed February 2017 by Michael Woods, MD, FAAP
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