by 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
Vitamin A deficiency is rare in the US, but it is common in developing countries. Here are some of the symptoms:
Vitamin A Toxicity
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.
Major Food Sources
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:
Tips for Increasing Your Vitamin A Intake:
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:
...(Click grey area to select URL)
Updated February 2015. Accessed February 24, 2016.
Fairfield KM, Fletcher RH. Vitamins for chronic disease prevention in adults: Scientific review. JAMA. 2002;287(23):3116-3126.
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.... 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
Last Updated: 2/24/2017
EBSCO Information Services is fully accredited by URAC. URAC is an independent, nonprofit health care accrediting organization dedicated to promoting health care quality through accreditation, certification and commendation.
This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.
To send comments or feedback to our Editorial Team regarding the content please email us at firstname.lastname@example.org. Our Health Library Support team will respond to your email request within 2 business days.
All rights reserved.