Facts

	Vitamin A is a fat-soluble vitamin that occurs in two forms: either as preformed vitamin A and provitamin A or carotene.1
	Vitamin A is primarily absorbed in the upper intestinal tract where bile and enzymes convert vitamin A into a form that the body can utilise. Carotene will be converted to vitamin A and will be absorbed in the same way as preformed vitamin A.
	Approximately 90 % of the vitamin A is stored in the liver with smaller amounts deposited in fat tissues, lungs, kidneys and the retinas of the eyes.

Functions

	Vitamin A prevents night blindness and has been shown, in therapeutic doses, to help with other eye problems.1,2
	Vitamin A has been shown to be helpful with some skin disorders such as acne.2 Applied externally, it also helps with impetigo, boils and open ulcers. Applied to wounds, it also speeds the healing process.1
	It is important for proper formation of teeth and bones, protects against colds, flu and infections of the kidneys, bladder, lungs and mucous membranes.1
	Vitamin A acts as an antioxidant, which has implications for cancer and cardiovascular disease.2

Requirements
The Recommended Daily Allowance has been set at 800 µg for Vitamin A.


Signs of Deficiency
Symptoms of a vitamin A deficiency include: dry hair or skin, sties of the eyes, loss of sense of smell, loss of appetite, skin blemishes (acne), diarrhoea, fatigue, poor growth and night blindness.1,2


Signs of Toxicity
Consuming large amounts of vitamin A over time can be toxic to the body, especially the liver. Symptoms of toxicity include: nausea, vomiting, diarrhoea, dry skin, hair loss, abdominal pain. Persons with liver disease, pregnant women should not take more than 10,000 IU of vitamin A daily. Children shouldn't take more than 18,000 IU.3


Current Research

Acne
In a study involving 100 patients, 100,000 IU of vitamin A was administered orally at bedtime. Of the 100 patients, researchers reported 36 were relived of acne, 43 reported an occasional outbreak.1 However, it is important to note the doses administered are nearly 20 times the RDA.

Stress Ulcers
In a study involving severely injured burn patients, researchers found that high doses of vitamin A reduced the risk of upper gastrointestinal bleeding ulcers.

Vitamins Home

1 Dunne, L.J. Nutrition Almanac, 3rd ed. McGraw-Hill Publishing Company, 1990: pp.12-17.

2 Balch, J.F. and P.A. Prescription for Nutritional Healing. Avery Publishing, 1997: pp. 13-14.

3 Erdman, J., Furr, H. Vitamin A. http://www.nutrition.org/nutinfo/content/via.shtml.

4 Barney, P. Doctor's Guide to Natural Medicine. Woodland Publishing, 1998: pp. 33.