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:
- Plays an essential role in vision
- Plays an important role in cell differentiation and cell division
- Helps in the formation and maintenance of healthy skin and hair
- Helps with proper bone growth and tooth development
- Helps the body regulate the immune system
- Plays an essential role in the reproduction process for both men and women
The recommended daily dietary allowance for vitamin A is measured in Retinol Activity Equivalents (RAE).
|Age Group (in years)||Recommended Dietary Allowance|
|1 – 3||300 RAE||300 RAE|
|4 – 8||400 RAE||400 RAE|
|9 – 13||600 RAE||600 RAE|
|14 – 18||700 RAE||900 RAE|
|14 – 18 Pregnancy||750 RAE||n/a|
|14 – 18 Lactation||1,200 RAE||n/a|
|19+||700 RAE||900 RAE|
|19+ Pregnancy||770 RAE||n/a|
|19+ Lactation||1,300 RAE||n/a|
Vitamin A Deficiency
Here are symptoms of vitamin A deficiency (rare in the US):
- Night blindness
- Dry skin
- Dry hair, broken fingernails
- Follicular keratinosis–hardened, pigmented goose bumps on the arms, legs, and hair follicles
- Decreased resistance to infections
- Loss of appetite
- Decreased growth rate
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 2,800 RAE daily. Symptoms of toxicity include the following:
- Dry, itchy skin
- Hair loss
- Loss of appetite
- Bone and muscle pain
- Liver damage
Vitamin A toxicity can cause severe birth defects. . Pregnant women, and those who may become pregnant, should limit their intake of vitamin A from dietary sources and supplements.
Major Food Sources
Vitamin A content
|Beef liver, cooked||3.5 ounces||8,025|
|Milk, fat-free||8 ounces||150|
|Whole egg, boiled||1 large||70|
|Milk, whole||8 ounces||70|
The following foods contain carotenoids, which the body converts into vitamin A.
Vitamin A content
|Sweet potato, mashed||1/2 cup||1,290|
|Carrots, raw||1 medium||515|
|Collards, frozen, boiled||½ cup||490|
|Red bell pepper, raw||½ cup||115|
|Kale, boiled||½ cup||445|
|Spinach, raw||1 cup||140|
Populations at risk for vitamin A deficiency
The following populations may be at risk for vitamin A deficiency and may require a supplement:
- People with a reduced ability to absorb dietary fat. Because vitamin A is a fat-soluble vitamin, fat is required for its absorption. Some conditions that can cause fat malabsorption include ]]>Crohn's disease]]> , ]]>cystic fibrosis]]> , ]]>celiac disease]]> , pancreatic enzyme deficiency, and liver disease.
- Children living in developing countries.
Tips for Increasing Your Vitamin A Intake:
Here are some tips to help increase your intake of vitamin A:
- Pack cut carrots in your lunch for an afternoon snack.
- Slice a peach, mango, or apricot on to your breakfast cereal or oatmeal.
- Substitute a sweet potato for your baked potato. Just poke holes in the sweet potato and cook at 350 degrees Fahrenheit for about 45 minutes to an hour (or microwave for 6 to 8 minutes).
- Eat fruits and vegetables raw whenever possible. Vitamin A can be lost during preparation and cooking.
- Steam vegetables, and braise, bake, or broil meat instead of frying. This will help retain some of the vitamin content.
Canadian Council on Food and Nutrition
Dietitians of Canada
Dietary Supplement Fact Sheet: Vitamin A and Carotenoids. Office of Dietary Supplements website. Available at: http://www.ods.od.nih.gov/factsheets/vitamina.asp . Accessed January 2, 2008.
Duyff RL. T he American Dietetic Association's Complete Food & Nutrition Guide . 3rd Ed. Hoboken, NJ: John Wiley & Sons, Inc; 2006.
Facts about dietary supplements. National Institutes of Health website. Available at: http://www.nih.gov .
Fairfield KM, Fletcher RH. Vitamins for chronic disease prevention in adults: scientific review. JAMA . 2002;287(23):3116-26.
Food and nutrition information center. US Department of Agriculture website. Available at: http://www.usda.gov .
The Nutrition Desk Reference . Keats Publishing; 1995.
Last reviewed February 2009 by ]]>Maria Adams, MS, MPH, RD]]>
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