title: The role of provitamin A carotenoids in the prevention and control of vitamin A deficiency.
abstract: That beta-carotene is the main source of vitamin A in fruits and vegetables has been known for many years. Many studies have been conducted to assess bioconversion of beta-carotene to vitamin A in animals. More recently, bioconversion studies using stable-isotopically labeled beta-carotene have been used to assess bioconversion in humans. The efficiency of the bioconversion of beta-carotene to vitamin A has been accepted to be six but this value may vary depending on vitamin A status and the amount of beta-carotene consumed. This paper reviews the human studies on purified beta-carotene supplements and/or consumption of fruits and vegetables conducted to ascertain whether beta-carotene can alter the vitamin A status of deficient populations. The conclusion is that data are lacking from well-designed studies to show that, with the possible exception of red palm oil, beta-carotene-rich foods are as effective as vitamin A supplements for eliminating vitamin A deficiency. Nevertheless, the data do show that beta-carotene-rich foods may be important for preventing vitamin A deficiency.
authors.forename: P
authors.initials: P
authors.lastname: Nestel
authors.forename: P
authors.initials: P
authors.lastname: Trumbo
mesh_terms: D002338:Carotenoids / Q000627:therapeutic use*; D016022:Case-Control Studies; D006801:Humans; D010938:Plant Oils / Q000627:therapeutic use; D015995:Prevalence; D014675:Vegetables; D014801:Vitamin A / Q000008:administration & dosage; D014802:Vitamin A Deficiency / Q000453:epidemiology / Q000517:prevention & control*; D019207:beta Carotene / Q000008:administration & dosage / Q000627:therapeutic use
chemical_list: D010938:Plant Oils; D019207:beta Carotene; D014801:Vitamin A; D002338:Carotenoids