Vitamin A is also known as retinol, it is a fat-soluble vitamin, it has two biologically active compounds namely retinaldehyde and retinoic acid. Retinaldehyde is an essential form of Vitamin A which is necessary for normal vision, whereas retinoic acid is necessary for cell differentiation and growth. Retinoic acid does not have a role in vision and in reproduction. Retinoids are required for fetal development, fertility, immune functions, deficiency of retinoid in children results in respiratory infections and gastroenteritis.

Vitamin A also have a role in T-cell mediated immunity ,humoral immunity,iron utilization,phagocytosis.

Vitamin A is available in the market as acetate or palmitate. Beta carotene is one of the most prevalent carotenoids in food that has provitamin A activity. The liver contains 90% of vitamin A reserves.and secretes Vitamin A in the form of retinol. Retinol is found only in food derived from animal origin and its richest source is liver. Vit A is also found in the intestine by splitting of carotenes, which is found in green vegetables, carrots, and some other fruits.

Deficiency of Vitamin A leads to :

1. Blindness.
2. Xerophthalmia.
3. Night blindness, it is the earliest sign of deficiency.
4. Hyperkeratotic skin.
5. Children with Vit A deficiency have an increased mortality rate, which is primarily from infectious disease, measles, diarrhea, respiratory disease.

Children are more susceptible to Vit A deficiency because breast and cow milk are not rich in vit A.

Diagnosis of Vitamin A deficiency:

Serum retinol tells about deficiency its normal range is 30 -60 microgram per decilliter.

Toxicity of Vitamin A :

Chronic toxicity of vit. A is seen in an adult who ingests 15 milligrams per day of vit A for several months and 6 milligrams per day for several months in children.

Dietary Source :

1. Beef liver > Lamb liver >Liver sausage (High to low)
2. Cheese (Goat cheese >Limburger Cheese>Blue Cheese> Cream Cheese) (High to low)
3. Fish like salmon and bluefin tuna.
4. Fish oil, like cod liver oil.
5. Hard-boiled egg.
6. Skimmed Milk (fortified milk), light whipping cream.
7. Butter.
8. Dark green leafy vegetables
9. Sweet Potato, Pumpkin.
10. Carrots.
11. Spinach.
12. Black-eyed pea.
13. Brocolli.
14. Mango.
15. Papaya.
16. Cantaloupe.
17. Trout.
18. Orange and yellow fruits.
19. Dried apricot, red bell pepper, pistachio, goji berries, tomato.
20. Grapefruit.