Vitamin A Information

There are two groups of Vitamin A, depending on whether the food source is an animal or a plant.

Vitamin A found in foods that come from animals is called Preformed Vitamin A. It is absorbed in the form of retinol, one of the most utilizable forms of vitamin A. Sources include liver, whole milk, and some fortified food products such as breakfast cereal.

Vitamin A that is found in colorful fruits and vegetables is called provitamin A carotenoid. They can be made into retinol in the body. Common provitamin A carotenoids found in foods that come from plants are beta-carotene, alpha-carotene, and beta-cryptoxanthin. Orange and yellow vegetables contain significant quantities of carotenoids. Major food plant sources of provitamin A carotenoids are carrots, sweet potatoes, cantaloupes, and spinach. Green vegetables also contain carotenoids, although the pigment is masked by the green pigment of chlorophyll.

The Institute of Medicine suggests consumption of all carotenoid-rich fruits and vegetables for their health-promoting benefits.

Even children who are only mildly deficient in vitamin A have a higher frequency of respiratory disease and diarrhea as well as a higher rate of mortality from infectious disease compared to children who consume sufficient vitamin A.

Source: Field CJ, Johnson IR, Schley PD. Nutrients and their role in host resistance to infection. J Leukoc Biol. 2002;71(1):16-32. (PubMed)