Carotenoids are a class of natural fat-soluble pigments found principally in plants, algae, and photosynthetic bacteria, where they play a critical role in the photosynthetic process. They also occur in some non-photosynthetic bacteria, yeasts, and molds, where they may carry out a protective function against damage by light and oxygen. Although animals appear to be incapable of synthesizing Carotenoids, many animals incorporate Carotenoids from their diet. Within animals, Carotenoids provide bright coloration, serve as antioxidants, and can be a source for vitamin A activity. Carotenoids are responsible for many of the red, orange, and yellow hues of plant leaves, fruits, and flowers, as well as the colors of some birds, insects, fish, and crustaceans.
In human beings, Carotenoids can serve several important functions. The most widely studied and well-understood nutritional role for Carotenoids is their provitamin A activity. Deficiency of vitamin A is a major cause of premature death in developing nations, particularly among children. Vitamin A, which has many vital systemic functions in humans, can be produced within the body from certain Carotenoids, notably beta-carotene. Dietary beta-carotene is obtained from a number of fruits and vegetables, such as carrots, spinach, peaches, apricots, and sweet potatoes. Other provitamin A Carotenoids include alpha-carotene (found in carrots, pumpkin, and red and yellow peppers) and cryptoxanthin (from oranges, tangerines, peaches, nectarines, and papayas). Carotenoids also play an important potential role in human health by acting as biological antioxidants, protecting cells and tissues from the damaging effects of free radicals and singlet oxygen. Other health benefits of Carotenoids that may be related to their antioxidative potential include enhancement of immune system function, protection from sunburn, and inhibition of the development of certain types of cancers.
References:
http://www.astaxanthin.org/carotenoids.htm
