title: Vitamin A value of plant food provitamin A - evaluated by the stable isotope technologies.
abstract: Humans need vitamin A and obtain essential vitamin A by conversion of plant foods rich in provitamin A and/or absorption of preformed vitamin A from foods of animal origin. The determination of the vitamin A value of plant foods rich in provitamin A is important but has challenges. The aim of this paper is to review the progress over last 80 years following the discovery on the conversion of β-carotene to vitamin A and the various techniques including stable isotope technologies that have been developed to determine vitamin A values of plant provitamin A (mainly β-carotene). These include applications from using radioactive β-carotene and vitamin A, depletion-repletion with vitamin A and β-carotene, and measuring postprandial chylomicron fractions after feeding a β-carotene rich diet, to using stable isotopes as tracers to follow the absorption and conversion of plant food provitamin A carotenoids (mainly β-carotene) in humans. These approaches have greatly promoted our understanding of the absorption and conversion of β-carotene to vitamin A. Stable isotope labeled plant foods are useful for determining the overall bioavailability of provitamin A carotenoids from specific foods. Locally obtained plant foods can provide vitamin A and prevent deficiency of vitamin A, a remaining worldwide concern.
authors.affiliation: Carotenoids and Health Laboratory, Jean Mayer USDA Human Nutrition Research on Aging, Tufts University, Boston, MA, USA.
authors.forename: Guangwen
authors.initials: G
authors.lastname: Tang
mesh_terms: D003903:Deuterium; D006801:Humans; D007553:Isotope Labeling; D009752:Nutritional Status; D014801:Vitamin A / Q000378:metabolism*; D019207:beta Carotene / Q000378:metabolism*
chemical_list: D019207:beta Carotene; D014801:Vitamin A; D003903:Deuterium
keywords: bio absorption; bio conversion; intrinsic labeling; provitamin A carotenoids; stable isotopes; vitamin A; β-carotene