14] Human metabolism of carotenoid analogs and apocarotenoids

Abstract

Publisher Summary This chapter describes the procedures for the preparation of carotenoid analogs, for the administration of doses, for blood sampling, for the high-performance liquid chromatography analysis of serum samples, and for the characterization of metabolites. Studies of the absorption and metabolism of carotenoids have been stimulated by claims of their anticarcinogenic properties independent of their provitamin A activity. Many epidemiological studies have indicated a possible association between increased dietary consumption of foods rich in carotenoids and a lower cancer risk. Carotenoids have been shown to have potent antioxidant activities, to stimulate the immune response and to protect cells and animals from cancerous events. However, little is known about the metabolism of carotenoids in humans, other than the cleavage of β -carotene to retinal in the gut, liver, and some other tissues. Studies on the metabolism of carotenoids in humans are complicated by the presence of dietary carotenoids and the slow clearance of endogenous carotenoids from human serum.