by Calvagna M

salad spinach eating pregnancy 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.

Functions

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

Recommended Intake:

The recommended daily dietary allowance for vitamin A is measured in micrograms (mcg) of Retinol Activity Equivalents (RAE).

Age Group (in years) Recommended Dietary Allowance
Females Males
1 – 3 300 mcg of RAE 300 mcg of RAE
4 – 8 400 mcg of RAE 400 mcg of RAE
9 – 13 600 mcg of RAE 600 mcg of RAE
14 – 18 700 mcg of RAE 900 mcg of RAE
14 – 18 Pregnancy 750 mcg of RAE n/a
14 – 18 Lactation 1,200 mcg of RAE n/a
19+ 700 mcg of RAE 900 mcg of RAE
19+ Pregnancy 770 mcg of RAE n/a
19+ Lactation 1,300 mcg of RAE n/a

Vitamin A Deficiency

Vitamin A deficiency is rare in the US, but it is common in developing countries. Here are some of the symptoms:

  • Night blindness
  • Decreased resistance to infections
  • Decreased growth rate
  • Problems with the cornea of the eye, including ulceration and scarring
  • Diarrhea

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:

  • Nausea
  • Vomiting
  • Headache
  • Blurred vision
  • Lightheadedness
  • Poor coordination

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

Food Serving size Vitamin A content
(mcg of RAE)
Beef liver, cooked 3 ounces 6,582
Milk, fat-free 8 ounces 149
Whole egg, boiled 1 large 75
Sockeye salmon, cooked 3 ounces 59

The following foods contain carotenoids, which the body converts into vitamin A.

Food Serving size Vitamin A content
(mcg of RAE)
Sweet potato, baked in skin 1 whole 1,403
Carrots, raw ½ cup 459
Mango, raw 1 whole 112
Red bell pepper, raw ½ cup 117
Cantaloupe, raw ½ cup 135
Apricots, dried, sulfured 10 halves 63
Spinach, cooked ½ cup 573
Tomato juice, canned 12 ounces 42

Health Implications

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.
  • 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.

RESOURCES

American Society for Nutrition  http://www.nutrition.org 

Eat Right—Academy of Nutrition and Dietetics  http://www.eatright.org 

CANADIAN RESOURCES

Dietitians of Canada  http://www.dietitians.ca 

Health Canada  http://www.hc-sc.gc.ca 

References

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. 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.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.

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