What is Vitamin A?

We all know that vitamins are organic compounds needed to provide vital nutrients to the body. Vitamin A is one such fat soluble vitamin. They are similar in structure and biologic activity of retinol. It is commonly found in two forms: Retinol and Carotenes

Functions of Vitamin A:

There are numerous functions of Vitamin A. Some of them are mentioned below:

  • Good Vision:

    Vitamin A is needed to maintain good vision. It is used for the treatment of such eye disorders as glaucoma, age-related macular degeneration (AMD) and cataracts. Vitamin A is needed for the formation of a specific metabolite-retinal which is crucial for low light vision.

  • Healthy Skin:

    Vitamin A is required for the maintenance of healthy skin. Beta carotene acts as a powerful antioxidant, weakening the molecules that are responsible for damaging the healthy cells. It is also used during the treatment of such skin conditions as eczema, cold sores, burns, sunburn, wounds, acne, pityriasis rubra pilaris etc.

  • Healthy Bone and Tooth Growth:

    It helps in the formation and maintenance of strong teeth and bones.

  • Cancer:

    Intake of Vitamin A supplements are known to be associated with lower risk of lung cancer.

  • Formation of new cells:

    Vitamins are also needed for the formation of new cells in the body, which are required for the development of normal brain and good functioning of the nerve.

Good Sources of Vitamin A:

 Some of the good sources of Vitamin A are:

  • Vitamin A from animal sources

    (Retinol): Eggs, meat, cheese, cream, butter, liver, kidney, cod, fortified milk, halibut fish oil, fortified margarine etc.

  • Vitamin A from plant sources

    (Beta-Carotene): Dark green vegetables, sweet potatoes, yellow and orange fruits (apricots, cantaloupe), carrots, winter squash, pumpkin, leafy vegetables, broccoli, spinach etc.

Vitamin A Deficiency:

Vitamin A deficiency is prevalent in many developing and poor countries. According to World Health Organization, the most common sign of vitamin A deficiency among pregnant women and young children is night blindness; inability to see in low light or darkness. Vitamin A deficiency can also lead to xerophthalmia (dry eyes) and even complete blindness. Vitamin A deficiency can lead to such infectious diseases as measles in young children. It can also lead to slow bone formation, respiratory infections and diarrhea. Pregnant women with vitamin A deficiency can die during pregnancy or childbirth.

Recommended Intake of Vitamin A:

Age Group Adequate Intake mcg/day Upper Limit mcg/day
Infants0-6 months7-12 months  400500  600600
Children 1-3 years4-8 years  300400  600900
Males9-13 years14-18 years19 -70 years  600900900  1, 7002,8003,000
Females9-13 years14-18 years19-70 years  600700700  1, 7002, 8003, 000
PregnancyUp to 19 years19 to 50 years  750770  2, 8003, 000
Lactation Up to 19 years19 to 50 years  1, 2001, 300  2, 8003, 000

 *The above chart applies to products coming from animal sources and from vitamin A supplements coming from retinol or ester forms.

Side Effects of Excessive Vitamin A: Constant intake of excess vitamin A can make you sick. While it may cause congenital birth defects in pregnant women, it may lead to poisoning in adults. Other side effects include dizziness, skin irritation, pain in bones and joints, headaches, nausea. It may take you to a coma and may even lead to death. These conditions are usually as a result of excessive vitamin A which contains product such as retinol. Large amount of beta- carotene can turn the skin yellow or orange.

Tips and Warnings:

  • Take vitamin A along with fatty foods for easy absorption.
  • For proper metabolism, take vitamin E along with your doses of vitamin A.
  • While taking vitamin A, avoid the use of mineral oil laxatives.
  • Decrease the intake of alcohol while consuming vitamin A.
  • Avoid the intake of vitamin A supplements or any cosmetic or skin care products containing retinols during pregnancy as that can act as a toxic to the fetus resulting in birth defects.
  • Always consult with your doctor if you are taking prescription medicines.