| Many
Eastern cultures, and perhaps some Western cultures, believed
that a baby should be exposed to the sun so that the baby will
develop strong bones. This belief is now backed by science. What
actually happens is that the sun’s ultraviolet rays activate a
certain substance in the skin. This substance is a precursor of
vitamin D. Once vitamin D is formed, it helps the body absorb
all the calcium it needs for forming and strengthening the bones,
the cartilage, and the teeth. In an indirect way, vitamin D or
calciferol helps a person have strong bones and teeth.
However, not everyone can use
sunlight in forming the needed vitamin D. Some people live in
places (such as North Pole) where there is no sun for quite
a long period. And some people live in places (such as Gobi
desert) where the rays of the sun are dangerous, even in the
early morning. Luckily, there are other sources of vitamin D,
such as fishes and egg yolks. Milk, which is often described
as a complete food, usually does not have vitamin D. But to
make milk a true complete food, some manufacturers fortify their
milk and other dairy products with vitamin D.
A lack of vitamin D leads to
imbalances in the biochemical and physiological make-up of the
human body. The formation and mineralization of bones and teeth
go awry. As a result, children suffer from rickets while adults
develop osteomalacia.
To detect early the presence
of rickets in a child, a parent must look for known symptoms
such as restlessness, profuse sweating and lack of muscle tone.
The child or baby will take a long time before he or she learns
to sit, crawl or walk. A child with rickets may have bowlegs
or knock-knees. It was through the study of rickets that Edward
Mellanby discovered vitamin D in 1922.
Osteomalacia is a condition
in which the bones of adults are progressively losing the calcium
mineral. Aside from this disease, a person who lacks vitamin
D may also suffer osteoporosis. This disease will make the bones
of a person prone to fracture.
Since vitamin D is fat soluble,
it is a vitamin that can be stored by the body. It implies that
vitamin D should not be ingested in large doses. When there
is too much of it, vitamin D becomes toxic. It will make a person
lose his appetite and his weight. He will experience nausea,
vomiting, and a general weakness. And he will suffer diarrhea. |
