Review: absorption and metabolism of beta-carotene.
To better understand the potential function of beta-carotene (beta-C) in the prevention of cancer, greater knowledge of beta-C metabolism and a suitable animal model to mimic human beta-C metabolism are necessary. The small intestinal mucosa contains beta-C cleavage enzyme(s), thereby playing an important role in both the provitamin A activity and anti-cancer properties of beta-C. The ability of the ferret (Mustela putorius furo) to absorb intact beta-C makes it an appropriate model for studying human beta-C absorption. This article reviews the absorption and cleavage mechanisms of beta-C in both the human and the ferret. The biosynthesis of retinoic acid (RA) from beta-C via central and eccentric cleavage pathways is reviewed. The possible significance of the conversion of beta-C to RA as an anticancer mechanism is discussed.
Gastroinestinal Nutrition Laboratory, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111.
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D000818:Animals; D002338:Carotenoids / Q000378:metabolism*; D005289:Ferrets / Q000378:metabolism; D006801:Humans; D007408:Intestinal Absorption; D008954:Models, Biological; D012176:Retinoids / Q000378:metabolism; D014212:Tretinoin / Q000378:metabolism; D019207:beta Carotene
D012176:Retinoids; D019207:beta Carotene; D002338:Carotenoids; D014212:Tretinoin