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Dr. Kenneth Walker
The Vitamins
QUESTION # 1
Discuss
the history of vitamins and their discovery?
Dr.
Kenneth Walker was a consultant surgeon in London. He has a neat simple and
straightforward style that suits his purpose excellently. "The Vitamins" is an extract from
his research work, "Human physiology". It is written in his typical
plain prose style.
In the beginning only five basic
ingredients of food were known. People tried to include all these ingredients
in food to make it a balanced diet. In 1906
Sir F. Gowland Hopkins conducted some experiment on rats. He kept these rats on a diet of pure
proteins, fats, carbohydrates, salts and water but still they developed the
signs of malnutrition. It diverted the
attention of scientists to another ingredient that was still not known. This ingredient was needed to keep ones body
perfectly healthy. Later experiments
discovered it and it was named as the vitamin.
In 1906 a disease called scurvy
invaded the ships of East India Company.
In order to combat this scourge, lemons and oranges were used, which are
a rich source of vitamins. Another
disease, which is thought to be due to vitamin deficiency, is beri-beri. It is characterized by weakness and even
complete paralysis of legs associated with dropsy.
The research on all these diseases
solidified the existence of vitamins and their importance for human body. The true nature of vitamins is still not
completely known and researches are still going on.
Q. No. 2: What
are the main types of vitamins?
The vitamins are divided in two
categories. This division is on the
basis of their solubility in fats or in water.
The letters of the alphabet are employed to distinguish them. The
fat-soluble vitamins are A, D, and E. The water-soluble vitamins are B and
C.
The first fat-soluble vitamin is
A. It is found in cod-liver oil in large
quantity. Its smaller amounts are present in butter and green vegetables. Deficiency of this vitamin results in stunted
growth and reduces the natural resistance offered by the body to invading
organisms. Its deficiency produces a dry
condition of eye known as Xerophthalmia.
The second fat-soluble vitamin is D.
It is found in cod-live oil and in lesser amounts in other animal fats but is
not present in vegetable oils. Its
absence from food interferes with the growth and calcification of bones and is
the cause of rickets. Rickets is cured
by adding vitamin D to diet or by exposing the patient to sunlight because
another major source of vitamin D is sunlight
The main water-soluble vitamins are
B and C. Vitamin B is found in yeast and
in the outer layers of rice and wheat.
Its absence causes beri-beri and pellagra. Vitamin B actually contains six different
substances of varying importance.
The second water-soluble vitamin C
is present in fresh vegetables, in germinating peas and beans and in some
fruits especially in lemons and oranges.
It is important as anti-scorbutic vitamin.
Still more vitamins are being
discovered and their efficacy is also being elucidated.
Q. No. 3: Discuss
the reasons of rickets?
Rickets is a disease characterized
by softening and bending of bones.
During the research on rickets, two completely divergent theories were
presented about its causes. According to
some investigators, it was purely a diet-deficiency disease. They proved that it could by readily cured by
adding a small quantity of cod-liver oil to diet of the patient. At the same
time, some investigators believed that it was related to the physical
environment of the patient because rickets almost always attacked children
living in dark industrial cities and was quickly cured when they were brought
into the sunlight.
On further investigations, it was
proved that the main cause was the deficiency of vitamins D and it can be
obtained either by mouth or skin. That's
why rickets may be caused by shortage of vitamins D or by the lack of sunlight.
Vitamin D is present in cod-liver
oil and animal fats. Similarly it can be
obtained through sunlight that transforms a certain fat found in the skin to
vitamin D.
So
this disease can be cured in these two ways.
Q. No. 4: What
should be done to fulfill the deficiency of vitamins?
Today we fully know the importance
of vitamins and we also know that the use of alkalis in flour grinding and in
the milling of rice is strongly helping in the destruction of vitamins found in
different foodstuffs. The governments and authorities do not pay attention to
it. So people should take steps to rectify
the situation by compensating the loss of vitamins by taking them in the form
of tablets. In this way the interests of
the government, millers and masses will be secured at the same time.