Totally Around Vitamin A
Vitamins are essential for good health and well being. They
are defined as any group of substances required in small quantities for healthy
growth and development. They cannot be manufactured in the body so they are
therefore vital constituents of the diet.
There are two types of vitamins according to whether they
are soluble in water or fat. Vitamin A (Retinol) is usually an excess fat
soluble vitamin and this isn't excreted from the body in the urine so excessive
intake can have a negative effect on health. Vitamin A is present in animal
origin foods eg. liver, milk and egg yolk. It is formed in the body from the
pigment Beta-carotene which is present in certain vegetables eg. carrots,
cabbage and lettuce.
Vitamin A has a number of roles in the body. It is necessary
for normal cell division and growth. It is important for maintenance of mucous
membranes of the repiratory, digestive and urinary tracts. Retinol is usually a
pale yellow solid which dissolves very easily in oil and excess fat and it is
essential for good eye sight, particularly vision in dim light and also having
an important role in normal development of the embryo. It can be produced
synthetically and therefore used to enrich margarines.
The best source of retinal is liver and a small amount 3g
meets the body’s daily requirements. 700mcg per day is an adequate amount per
adult which can also be derived from the beta carotene foods eg. 2oz raw
carrots.
Deficiency of Vitamin A causes stunted growth, night
blindness and drying up of mucous membranes which increases the risk of
contamination. A continued lack of Vitamin A can lead to worsening of vision an
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