Vitamin A or Retinol

Vitamin A is a fat-soluble vitamin that occurs in two forms in nature.
It is found in its true form (also called retinol) in animal foods such as fish oils and liver. The body readily uses this form.

Vitamin A can be found in vegetables in the form of beta-carotene or provitamin A. This form is found in plants and is the precursor of the actual vitamin. Beta-carotene has to be converted in the body in order to be used by it. Fat and bile are needed for the conversion.

The liver regulates the blood level of vitamin A. It needs a special protein carrier to be transported throughout the body.
An adequate protein and fat intake is required for a good absorption of vitamin A.

It is an anti-oxidant, a compound that may protect against disease by neutralizing unstable oxygen molecules, called free radicals, within the body.
This vitamin is involved in the night vision, growth, cell differentiation and reproduction. It also maintains the health of the skin (prevents acne and dermatitis) and surface tissues especially those with mucous linings. These linings are the body first defense against infection that is why vitamin A helps fight colds and infections, particularly in the mucous membranes of the eyes, ear, nose, throat, lungs and bladder.
It may also reduce breast cancer.

Units of measurement
Vitamin and mineral amounts are usually expressed in milligrams (mg) or micrograms (mcg).
Vitamin A values are expressed in different ways.
The nutriment was originally measured in I.U (international unit) but in 1974 the United States began using a measurement called Retinol Equivalents (REs).

1 RE = 1 mcg. of retinol
1 RE = 6 mcg. of beta-carotene
1 RE = 3.333 U.I of vitamin A


Recommended Dietary Allowance (RDA) for the French population.
RE per day
Babies 0 to 1 years
Children 1 to 3 years
Children 4 to 6 years
Children 7 to 9 years
Children 10 to 12 years
Teenager boy 13 to 15
Teenager girl13 to 15
Teenager boy 16 to 19
Teenager girl 16 to 19
Pregnant women
Nursing mother

Deficiency symptoms

A deficience in vitamin A can lead to:

Good vegetarian sources
Animal products are good sources of vitamin A. Vegetarians have to know where to find beta-carotene (the precursor of vitamin A) to insure their intake in vitamin A.
Beta-carotene is found in abundance in bright yellow, orange, red and dark green fruits and vegetables.

RE per 100 grams
Carrots, raw 2574
Carrots, cooked 2455
Spinach, raw 674
Spinach, cooked 743
Sweet potato, cooked 2180
Squash, cooked 714
Dandelion, raw 1400
Red pepper, raw 580
Red pepper, cooked 558
Mash, raw 708
Mango, fresh 523
Apricots, dry 730
Apricots, fresh and pitted 260
Cantaloup 322
Wheat germ 160
Spirulina 28333
Nori 4895
Kombu 1623
Dulse 266
Aonori 150

Vitamin A is a fat-soluble vitamin, which means it can be stored in the body and can lead to over doses.
Very high doses of vitamin A can cause side effects such as headache, vomiting, blurred vision, hair loss, liver damage and aching bones.

Realized by Laurence LIVERNAIS-SAETTEL, Dietitian.
© Copyright L. Livernais-Saettel 2000
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