Vitamin A Deficiency
Vitamin A is a substance known as retinol. It is a fat-soluble vitamin, which is important for vision, proper function of immunity and integrity of mucosal surfaces. Vitamin A is present in a variety of animal and plant foods. A large amount of it is in the liver, fish oils, in carrots, broccoli, spinach, eggs, sweet potatoes and many others. The natural resource is their mother's milk.
The cause of vitamin A deficiency is usually its unsatisfactory dietary intake, which is especially the problem of developing countries of Africa. In addition, the lack of vitamin A is more common in patients with malabsorption of nutrients in the digestive tract, typically in disrupted fat absorption.
Vitamin A is essential for proper formation of visual pigment called rhodopsin, which is essential for vision in darker environment. Therefore, vitamin A deficiency leads to visual impairment, which is evident in dim-lighted environment. More serious is dysfunction of mucosal tear ducts leading to drying up of the conjunctiva and cornea. If this condition is not solved, it may eventually cause an irreversible eye damage and permanent loss of vision. People with vitamin A deficiency have generally reduced mucosal immunity, which is accompanied with recurring respiratory and urinary infections.
Regular intake of the vitamin A in the diet is needed. If necessary, the vitamin may be administered in dietary supplements. However, cautious approach is advised as inadequately high intake may cause severe overdose with multiple organ failure and fatal consequences.