The World Health Organization (WHO) estimates that over four million children under five years of age are affected by vitamin A deficiency, resulting in increased vulnerability to common childhood diseases (such as measles, diarrhea, and malaria) and leading to the deaths of one million children each year.
Vitamin A deficiency is among the most common and serious of all nutritional deficiency diseases. But it is also the one for which there is the greatest hope for control and prevention within the forseeable future. In recent years, startling scientific discoveries have been made that reveal how vitamin A functions as a hormone at the cellular level in many systems of the body.
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Some years ago it was believed that disease resulted only from severe vitamin A deficiency and that it was confined to being a major cause of blindness in young children (xerophthalmia). Although xerophthalmia is much less common than it used to be, due in part to the many prevention programs that have been set up, many children still go blind every year. However, over and above this, vitamin A deficiency can lead to a much greater risk of death and also predispose those affected to contracting infectious diseases.
Of great importance is the fact that these risks occur when the level of vitamin A deficiency is “subclinical” – that is to say, there is no clinical disease and the deficiency can be revealed only by carrying out biochemical or other laboratory tests. This subclinical deficiency is much more common and widespread than clinical deficiency, like xerophthalmia. It affects mainly young children and their mothers during pregnancy and lactation. This means that the greatest emphasis now needs to move away from blindness and the eye to the area of Maternal and Child Health (MCH).
All health workers need to be aware of what is going on in the field of vitamin A. Compared to the common occurrence of its deficiency, an excess of vitamin A is very rare but it can lead to disease and caution should be practiced. Hence the importance of ensuring that vitamin A supplementation is administered according to international standards and guidelines.
SIGHT AND LIFE released various books on Vitamin A deficiencies. Additionally, SIGHT AND LIFE supported a program to develop a simple calculation of vitamin A intake. | |
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