title: Bioavailability of carotenoids.
abstract: Our current knowledge about the bioavailability of provitamin A carotenoids in foods is insufficient, fragmentary and difficult to interpret. Past methods of estimating the vitamin A value of food carotenoids suffer both from uncertainty about the meaning of bioavailability and from the inadequacy of the indicators used in its determination. Reported conversion ratios of beta-carotene to vitamin A in humans in vivo, depending on conditions, range from 2:1 to 26:1 (microgram/microgram). Thus, the ratio of 6:1, devised by the World Health Organization, must be considered as a rough average estimate that is not applicable to all diets. Strategies to increase the dietary intake of carotenoid-containing foods should include measures to enhance carotenoid bioavailability.
authors.affiliation: Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Olson
mesh_terms: D000042:Absorption; D000818:Animals; D001682:Biological Availability; D002338:Carotenoids / Q000493:pharmacokinetics*; D004032:Diet; D006801:Humans; D014801:Vitamin A / Q000008:administration & dosage / Q000493:pharmacokinetics*; D019207:beta Carotene / Q000493:pharmacokinetics
chemical_list: D019207:beta Carotene; D014801:Vitamin A; D002338:Carotenoids