Distribution and metabolism of dietary carotenoids in humans as a criterion for development of nutritional supplements*
Frederick Khachik
Department of Chemistry and Biochemistry, Joint Institute for Food Safety and Applied Nutrition (JIFSAN), University of Maryland, College Park, 20742 MD, USA
Abstract: There are approximately 40-50 carotenoids in commonly consumed fruits and vegetables in a typical U.S. diet. These can be divided into carotenoid epoxides, mono- and dihydroxycarotenoids, hydrocarbon carotenoids, and carotenol acyl esters. However, among these, only a selected group of carotenoids are routinely found in human plasma, breast milk, major organs, and ocular tissues. In addition, several carotenoid metabolites have also been isolated and characterized from human plasma, tissues, and ocular tissues. The proposed metabolic transformation of carotenoids in humans will be discussed. Dietary carotenoids and their metabolites have been implicated in the prevention of cancer, cardiovascular disease, and age-related macular degeneration (AMD). An approach for the development of a nutritional supplement that is based on the distribution of carotenoids and their metabolites in humans will be discussed.
Keywords: food carotenoids; human plasma carotenoids; carotenoid metabolism; carotenoid oxidation products; HPLC analysis of carotenoids; multicarotenoid nutritional supplement.
*Paper based on a presentation at the 14th International Symposium on Carotenoids, Edinburgh, Scotland, 17-22 July 2005. Other presentations are published in this issue, pp. 1477-1557.