A vitamin A deficiency occurs when a person consistently consumes or retains less vitamin A than the body requires to properly function. Vitamin A deficiency most commonly occurs in people that live in developing and under-resourced nations around the world and is not commonly seen in nations that are generally considered to be more affluent. A deficiency in vitamin A can be avoided or addressed by consuming foods rich in vitamin A or by taking vitamin A supplements.
Vitamin A is a fat-soluble vitamin, which means that it dissolves in fat. Once absorbed in the body, fat-soluble vitamins are stored in the liver and in the body’s fatty issue. This is in contrast to water-soluble vitamins, which are dissolvable in water and are quickly eliminated from the body. Vitamin A helps the body maintain a healthy immune system, is an important component of healthy hair and skin, preserves the lining of the body’s organs and helps in maintaining vision.
It is estimated that somewhere between 250,000 and 500,000 children in impoverished nations lose their vision due to a vitamin A deficiency each year. Blindness from a lack of vitamin A typically occurs because vitamin A helps to keep the cornea and retina moist. Without sufficient levels of vitamin A, the cornea or retina may be more susceptible to damage from a lack of moisture, which can lead to blindness. A vitamin A deficiency can also lead to a condition known as night blindness, which inhibits the eye’s ability to adjust to dark conditions.
The main cause of a vitamin A deficiency is the inadequate consumption of foods that contain vitamin A. Foods that are rich in vitamin A include vegetables such as sweet potatoes, carrots, spinach, romaine lettuce and turnips and fruits such as mangoes, papayas, apricots and cantaloupes. Other foods that provide a good amount of vitamin A include milk, eggs, and foods that have been fortified, or have had vitamin A added to it.
While vitamin A consumption is important, too much vitamin A can be harmful. As with all fat-soluble vitamins, the body stores excess amounts of vitamin A in the liver and fatty tissues for future use. Excessive levels of vitamin A in the body can cause problems with the liver, lead to birth defects, cause itchy or dry skin, affect the central nervous system, lead to headaches, dizziness, blurred vision and osteoporosis. An excessive amount of vitamin A in the body is typically caused by the overuse or unnecessary consumption of vitamin A supplements.