| Vitamin A deficiency is one of the most serious
nutritional deficiency diseases in the world today. It is wide spread in South East Asia,
the Middle East, Africa, Central and South America, particularly in children and is
associated with general malnutrition. It is one of the most prevalent deficiencies in
India and is seen among children. Causes of Deficiency
Inadequate intake of vitamin A, malabsorption disorders like sprue, faulty metabolism
of fats and protein energy malnutrition can cause vitamin A deficiency.
Signs and Symptoms
Night blindness is the most recognisable manifestation of vitamin A deficiency.
This occurs when there is insufficient vitamin A to bring about complete regeneration of
rhodopsin or visual purple.
Epithelial changes:
Keratinization - this is a noticeable shrinking, hardening and degeneration of cells which
increases susceptibility to severe infection of the eye, nasal passages, ears, lungs, and
urinogenital tract.
In severe deficiency, follicular hyperkeratosis occurs, i.e. the skin becomes rough, dry
and scaly.
The first mild symptoms are mild sensitivity to bright light called photophobia. Sometimes
itching, burning and inflammation of the upper eyelids occur.
The final stage is keratomalacia, which is softening of the cornea. At this stage,
permanent blindness sets in which is incurable.
Prevention and treatment
A diet rich in carotene should be consumed and care should be taken for the vulnerable
group (children from 0-5 years of age). In areas where vitamin deficiency is endemic, then
an improved diet does not have much scope. Prophylactic (large) doses of vitamin A can be
administered. In conditions of obvious symptoms of the vitamin deficiency, therapeutic
doses of one Lac I.U. (international units) = 0.3 I.U. of retinol is given daily for 3
days.
Vitamin A
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