This is a fat soluble vitamin absorbed from the small intestine along with dietary fat. It is well known that carrots contain beta carotene, a substance that is converted into vitamin a by our body. But beta carotene is also found in most orange yellow fruits and vegetables, along with dark green vegetables.
Vitamin A functions:
Vit A has three basic functions
1. Vision : In medical terminology vitamin a combines with a protein called opsin to form rhodopsins in the rod cells of retina. When vit A inadequate , the lack of rhodopsin makes it difficult to see in dim light.
2. Growth and development of tissues : It is involved in normal cell differentiation; a process through which the embryonic cells develop and transform into mature tissue cells highly specific and different functions. Vit A also supports male and female reproductive processes and bone growth.
3. Immunity : Vit A is essential for immunity functions and its deficiency is associated with decreased resistance to infections. The severity of some infections, such as measles and diarrhea, is reduced by vit A supplementation among those who suffer from vitamin A deficiency.
Vitamin A deficiency symptoms:
Knowing the vitamin A functions, the deficiency symptoms are accordingly.
Poor growth
Night blindness
Blindness
Dry skin
Vitamin A rich foods:
Liver
Fortified milk
Fish liver oils
Red, green, and yellow vegetables ( spinach, lettuce, cabbage, sweet potatoes, green beans, fresh peas, tomatoes, pumpkin )
Orange fruits
Wheat bran, wheat bread
Another important fact about vitamin A is its toxicity. As the fat soluble vitamins are excreted more slowly than the water soluble vitamins, with the exception of vit K, vit A and D tend to accumulate in the body and cause toxic effects. So vit A supplementation without doctor’s advice is not prescribed. And in fact the deficiency of vit A is not so common in developed countries as in developing nations.