| Beta carotene
is a compound that occurs naturally in carrots and gives this
vegetable its orange color. It was first isolated by Wackenroder
in 1831 and its chemical structure was explained by Karrer, who
won the Nobel Prize for it. Then, another scientist, named Steenbock,
suggested that beta-carotene is a pro-vitamin. A pro-vitamin is
a compound that can be changed by the human body to form a vitamin.
Beta-carotene is a pro-vitamin or precursor of Vitamin A, which
is also known as retinol. Vitamin
A is known for three important functions. It is excellent for
maintaining good vision. It helps in bone and teeth development.
And it is effective in maintaining the youthfulness of the skin.
There is, however, another important function of vitamin A.
This vitamin can help the body build resistance against certain
types of cancer. Studies have revealed that among people who
are deficient in vitamin A, most of them suffer from lung cancer.
And many scientists tend to believe that it is the effect of
vitamin A which is responsible for the anti-cancer action of
beta-carotene.
The known sources of vitamin A are eggs, milk,
spinach, sweet potatoes, apricots, cantaloupe, and carrots.
Since beta-carotene is a precursor of vitamin A, cruciferous
vegetables that are rich in beta-carotene can also be considered
as sources of vitamin A. Some cruciferous vegetables are broccoli,
cauliflower, brussels sprouts and cabbage. Vitamin A can also
be found in butter. The margarine, a substitute for butter,
is fortified with vitamin A so that the margarine’s nutritional
value will nearly be equal to that of butter. Both beta-carotene
and vitamin A are used as food additives – as vitamin additive
and as color additive.
Children who eat foods rich in vitamin A can
store this vitamin in their bodies for many years. As they grow
older and develop their bones, they use up some vitamin A. Thus
it is important for adults to replenish their stock of vitamin
A in the body. But for children who had less intake of vitamin
A, they suffer abnormal bone development. They have rough and
dry skin. And they experience night blindness, a blurring of
vision that starts at every dusk and this may eventually lead
to a complete loss of sight. They develop xerophthalmia, a condition
in which the cornea of the eye has dried.
However, too much vitamin A can be toxic. A
vitamin A poisoning is indicated by nausea, fatigue, and drowsiness.
A person may also feel pain in his bones, and may lose his hair.
His skin also becomes dry and scaly. Some adults will have blurred
vision and headache. While children become irritable. The children’s
growth becomes stunted and their livers will be abnormally large. |
