|
Vitamin A resides exclusively in yellow animal fats, such as egg
yolks, milk, and cheese. It is particularly abundant in fish liver oils, which
are utilized to prevent and cure ailments resulting from a deficiency of vitamin
A. In a well-nourished and healthy individual, the liver can store an ample
supply of vitamin A to satisfy the body's requirements for half a year.
While plants themselves do not contain vitamin A, many of them produce a
substance called carotene, derived from the green pigment in leaves, which our
bodies can convert into vitamin A. Carotene is the reddish-yellow pigment found
in carrots. Generally, the greener a leaf is, the greater the quantity of
carotene it contains. This underscores the significance of including green,
leafy vegetables in one's diet as a source of carotene. Tomatoes, papayas,
mangoes, and bananas contain more carotene compared to most other fruits. Red
palm oil possesses such a high concentration of carotene that it is used as a
substitute for cod liver oil, rendering it highly valuable both as a dietary fat
and for deep-frying.
Both vitamin A and carotene are insoluble in water and are resistant to
destruction by heat unless exposed to oxygen. Therefore, boiling in water does
not cause significant loss of vitamin A or carotene.
Vitamin A promotes robust growth and physical well-being. Young animals cease
growing and perish if they lack vitamin A in their diet. This vitamin sustains
the health of the moist surfaces lining the digestive tract, lungs, and airways.
It also aids in the proper functioning of glandular ducts, the tissue that
covers the eyelids and envelops the front of the eyeball. Because vitamin A
enhances the resistance of these tissues against infections, it is often
referred to as the anti-infective vitamin.
A scarcity of vitamin A frequently leads to common disorders in individuals,
characterized by dry and roughened moist tissues. This often results in severe
eye ailments followed by infections in the airways. The skin may also become dry
and rough. Another deficiency caused by inadequate vitamin A is
"night-blindness," where affected individuals experience clear vision only in
bright light.
Since the body is unable to produce vitamin A on its own, it must be obtained
from external sources. Therefore, a well-rounded diet is essential and generally
sufficient to meet the required intake. Consequently, there is no need to
supplement this necessity in the form of pills. |
