Vitamin A is a fat-soluble vitamin that is essential for humans. Ideally, vitamin A and its precursors are taken in with food. Vitamin A is only found in animal foods, such as milk, cheese, fish and liver. There are also provitamins, beta-carotene and alpha-carotene. Beta-carotene is considered to be better absorbed by the body. Provitamins A are found in plants such as carrots and green vegetables. Vitamin A and its precursors are absorbed into the body from food in the small intestine. The precursors of the vitamin are converted in the body and are then available as active vitamin A. This process is closely related to fat metabolism. Since vitamin A is a fat-soluble vitamin, the body can store it. For the most part, this happens in the liver. Vitamin A has a number of functions in the body. For example, it plays an important role in iron metabolism and in the formation of red blood cells.