Vitamin A Food Sources, Deficiency, Supplements and Dosages

What is vitamin A?

Vitamin A is essentially a fat soluble vitamin, meaning that it requires fat for its absorption into the body. Vitamin A us needed by organs such as the retina of the eye, where it is required for promoting good vision and helps eliminate the problem of night blindness. It is also required for reproduction, immunity, normal growth in children and development of the unborn child.

Forms of Vitamin A

Vitamin A is found in two different forms in foods :

  • Retinol which is the active form of vitamin A.
  • Carotenoids or more precisely ? carotene, the inactive form which  is present in all yellow-orange coloured fruits and vegetables. It is converted to vitamin A in the body.

Sources of Vitamin A

The food sources rich in vitamin A are of animal origin and includes

  • fish and fish oils
  • eggs
  • meat
  • cheese
  • milk and dairy products
  • kidney
  • liver

Plant sources rich in vitamin A include :

  • carrots
  • pumpkin
  • sweet potatoes
  • cantaloupe
  • spinach
  • broccoli
  • squash

Plant sources of vitamin A are seen as the better option by health conscious patients as they have zero in fat and cholesterol.

Vitamin A Deficiency

Deficiency of Vitamin A is fairly common and rampant in the developing countries. Vitamin a deficiency occurs in several stages :

  1. Initially night blindness is obvious wherein the individuals are unable to clearly visualize objects in dim light.
  2. If the deficiency is not treated, it may progress to cause xeropthalmia (dryness of the eyes), Bitot’s spot and keratomalacia (destruction of the cornea).
  3. As the deficiency worsens, it may eventually lead to complete blindness.

Apart from these deficiencies of vitamin A, it may also cause decrease immunity which causes a person to become prone to infections, damaged teeth enamel and hyperkeratosis. Hyperkeratosis is a condition marked by the formation of white lumps at hair follicles.

Dosage of Vitamin A Supplements

In order to correct the effects of vitamin A deficiency, immediate supplementation is advisable. The supplementation dose varies with the age of the individual. It is always better to adhere to the supplementation guidelines provided by the Food and Nutrition Board of the Institute of Medicine. RDA (Recommended Dietary Allowances) is the amount of vitamin A or any other nutrient that a person should get from their diet or supplements each day. The guidelines based on age groups are as follows :

  • Infants :
    – 0 to 6 months : 400mcg / day (400 micrograms per day)
    – 7 to 12 months : 500 mcg/day.
  • Children :
    – 1 to 3 years : 300mcg/day
    – 4 to 8 years : 400 mcg/day
    – 9 – 13 years: 600 mcg/day
  • Adolescents and adults :
    – Males aged 14 and above : 900mcg/day
    – Females aged 14 and above : 700mcg/day

It needs to be understood that during certain biological conditions such as pregnancy and lactation the requirements are different from the dosages mentioned above. Always consult with a medical doctor if you think that you have a vitamin A deficiency. The necessary tests will first be conducted to confirm the extent of the deficiency. Your doctor will the prescribe the appropriate dosage for supplementation.

Eating a healthy and balanced diet is one way of preventing a deficiency before it starts and is often the better option for correcting any nutritional deficiency in the very early stages.