Vitamin A is a fat-soluble vitamin, naturally present in foods. It plays an important role in vision, the immune system and reproduction. It also optimizes the heart, lung and kidney functions.
There are two types of vitamin A: the one that is already formed in foods, such as beef, chicken, fish and dairy products, and provitamin A. The latter is found in fruits and vegetables, as well as in other plant foods. The type of provitamin A most commonly found in foods is beta-carotene.
Vitamin A deficiency is very frequent in developing countries. The most common sign of this deficiency in children and pregnant women is and eye disease called xerophtalmia. This condition is characterized by a difficulty seeing in low lighting and, if untreated, can lead to blindness.