Vitamin A deficiency can have two different causes. The first cause of vitamin A deficiency is called a primary deficiency which is when not enough vitamin A is consumed by the individual. A secondary deficiency in vitamin A is when the individual consumes enough vitamin A, but the vitamin A is either not absorbed correctly or utilized correctly. Because vitamin A has many functions throughout the body, a vitamin A deficiency will have a large number of seemingly random symptoms. These symptoms can be both temporary and easily reversible, or the symptoms can be permanent.
The primary source of vitamin A deficiency is not enough vitamin A or beta carotene in the diet. Vitamin A rich foods can be both from animal and plant sources. Liver, eggs, cheese are all animal sources of vitamin A while carrots, broccoli and leafy vegetables such as spinach provide large amounts of beta carotene, which is converted by the body into vitamin A. A lack of proper daily intake of vitamin A will result in symptoms of vitamin A deficiency.
A secondary cause of vitamin A deficiency and its symptoms is when the ingested vitamin A is not absorbed by the small intestines or when it is not released by the liver when needed. Because vitamin A is fat soluble, it can be stored by the liver, but certain diseases, especially damage to the liver from alcoholism can reduce the ability of the liver to release vitamin A properly. There are a large number of conditions that can cause vitamin A to not be absorbed from food sources in the small intestines. Zinc is needed by the small intestines to absorb vitamin A, therefore a deficiency in zinc will often lead to a deficiency in vitamin A. Because vitamin A is transported into the body along with fats, any condition that impairs fat absorption can lead to vitamin A deficiency. The most common of these is liver disease that results in poor bile quality.
Because vitamin A has so many roles in the body, a deficiency will results in a large number of seemingly unrelated symptoms. The most common short-term and reversible symptoms include poor dim light vision, poor hair and skin quality, and muscle fatigue. Because of vitamin A’s role in mucous production, a short term deficiency can also lead to increased instances of upper respiratory infections. If the vitamin A deficiency is prolonged, these symptoms can turn into permanent problems.
There are many long-term, irreversible symptoms of vitamin A deficiency that can occur. The most common, especially in underdeveloped countries is blindness. Vitamin A is necessary to the proper maintenance of the retina and a deficiency will result in the retina drying out and become permanently damaged. Another permanent symptom of vitamin A deficiency in underdeveloped countries is improper muscular development in children. Vitamin A is an important nutrient in the growth and development of muscles and bones in children, and a vitamin A deficiency during crucial growing years results in permanently undersized individuals. Finally, vitamin A deficiency can result in permanent damage to the respiratory tract and lungs, which would result in increased infections along with poor oxygen, carbon dioxide exchange.
Symptoms of short term vitamin A deficiency include poor vision, poor hair and skin quality and weak muscles. A prolonged deficiency, especially in children can result in the symptoms of total blindness and decreased body size. The most common cause of vitamin A deficiency is improper nutrition, especially the consumption of vitamin A or beta carotene. A zinc deficiency, or damage to the liver or small intestines can also result in symptoms of vitamin A deficiency, even in individuals eating foods high in vitamin A.
