by
Ranjani Ramesh,
B. Sc., Pg Dip. in clinical nutrition Sri Ramachandra Medical College
Article date:June 2002
Fresh
food vitamin - Vitamin 'C'
Vitamin-c
has been called the fresh food vitamin since it is found in highest
concentration fresh as the food is fresh from the plant. Vitamin-c is a
water soluble vitamin which cannot be synthesized in the body and hence
has to taken in the diet. Vitamin c is known as ascorbutic vitamin,
because it cured a deficiency disease called scurvy which was prevalent
among sailors who could not get fresh fruits and vegetables for long
periods when they were in ship.
Role of Vitamin-C in our body
It is
an important antioxidant and thus has a role in the protection of
Vitamin A and E and the polyunsaturated fatty acids from excessive
oxidation.
It
also plays a role in the conversion of cholesterol to bile acids.
It
plays an important role in the wound healing by its role in the
formation of collagen.
It
builds up the resistance against infection by inactivating bacterial
toxins.
It
enhances the absorption of iron and also helps in the utilisation of
iron from its storage form.
It is
required for the normal maturation of red blood cells.
Vitamin
C also plays a role in some hydroxylation reactions one of which is
in the conversion of tryptophan to serotonin an important
neurotransmitter and vasoconstrictor. It is also involved in the
formation of tyrosine from norepinephrine. These reaction may
suggest the abnormalities in vascular and neurologic activity in
person deficient in vitamin C.
It is
also said to have a role in the synthesis of mucopolysacharides,
microsomal drug metabolism, leucocyte function and synthesis of anti
inflammatory steroids by the adrenal gland.
Effects
of Deficiency of Vitamin C:
A diet history, the concentration of ascorbic acid in blood plasma and
the white cells and a measure of the excretion of a test dose in the
urine help to establish the diagnosis.
A deficiency of this vitamin results in defective formation of the
intracellular cement substance, fleeting joint pains, irritabilities,
retardation of growth in the infant or child, anemia, shortness of
breath, poor wound healing and increased susceptibility to infection are
among the signs of deficiency.
Scurvy :
the incident of scurvy is uncommon in infants but a gross deficiency of
this vitamin results in scurvy during the second six months of life.
Scurvy in adults results after several months of diet devoid of vitamin
C. Symptoms include petechia or hemorrhagic spots on the skin, swelling,
infection and bleeding of the gums, tenderness of the legs and anemia.
the teeth may become loose and may be lost. As the disease progresses
the slightest injury produces excessive bleeding and large hemorrhages
may be seen underneath the skin.
Acute scurvy responds within few days to the administration of 100-200mg
of ascorbic acid given in the synthetic form or as orange juice.
Sources of this vitamin
Raw, canned or frozen citrus fruits such as orange, grape, lemons are
excellent sources of vitamin C. orange sections including the thin white
peel contains more vitamin C than an equal weight of strained fruit
juice.
Rich sources of Vitamin C.
Almost all the daily intake of ascorbic acid / vitamin C is obtained
from the vegetables and fruits. In general the active part of the plant
contains appreciable amounts and mature or resting seeds are devoid of
vitamin C.
Orange, lemon, grapes, fresh strawberries, cantaloupe, pineapple and
guava.
Small amt can be obtained from peaches, bananas, pears, apple
blueberries.
In vegetables Broccoli, Brussels, sprouts, spinach, kale, green pepper,
cabbage and turnips are excellent - good sources of vitamin C.
Milk,
eggs, meat, fish and poultry are devoid of vitamin C.
Retention of the vitamin in the food :
A
warm environment, exposure to light and solubility in water, heat,
alkalies and dehydration are detrimental to the retention of vitamin
C or ascorbic acid in the food
Cutting
of vegetables releases oxidative enzymes and increases the surfaces
exposed to leaching by water. Since the vitamin is so soluble,
losses are considerable when large amounts of water is used
Vegetables
should be added to a small quantity of boiling water, covered
tightly and cooked until just tender for high retention of vitamin
C.
Retention
is also good when the vegetables are pressure cooked. the practice
of adding baking soda is to retain the colour of the vegetable but
it reduces the vitamin level in the vegetable and may also change
the taste and flavour. Instead if turmeric powder is used it retains
colour and adds taste to vegetable, Turmeric powder is said to have
medicinal properties too.
Vegetables
left over should be covered tightly and refrigerated to preserve the
vitamin C
On
the other hand , citrus fruits and tomatoes retain practically all
the vitamin C value for several days
Now that
u all know that this vitamin has so many functions in our body, do
include ascorbic acid in your diet everyday in the form of fruits or
vegetables.
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