Relative vitamin A values of 9-cis- and 13-cis-β-carotene do not differ when fed at physiological levels during vitamin A depletion in Mongolian gerbils (Meriones unguiculatus). (8th April 2014)

• Record Type: Journal Article
• Authors: Bresnahan, Kara A.; Davis, Christopher R.; Tanumihardjo, Sherry A.
• Is Part Of: British journal of nutrition. Volume 112(2014)Supplement 2
• Page Start: 162
• Page End: 169
• Publication Date: 2014-04-08
• Subjects: β-Carotene, -- Bioavailability, -- Bioconversion, -- Isomer effects; Nutrition -- Periodicals; 572.4
• DOI: 10.1017/S0007114514000658
• Languages: English
• ISSNs: 0007-1145

Abstract

Abstract : Provitamin A biofortification of staple crops may decrease the prevalence of vitamin A (VA) deficiency if widely adopted in target countries. To assess the impact of processing methods on the VA value of plant foods, the unique bioefficacies of cis -βC isomers (formed during cooking) compared with all- trans (a t ) β-carotene (βC) must be determined. The bioefficacies of 9- cis (9 c )- and 13- cis (13 c )-βC isomers were compared with those of the a t -βC isomer and VA positive (VA+) and negative (VA − ) controls in VA-depleted Mongolian gerbils ( Meriones unguiculatus ) in two experimental studies (study 1, n 56; study 2, n 57). A 3- or 4-week depletion period was followed by a 3- or 4-week treatment period in which the groups received oral doses of the 9 c -, 13 c - or a t -βC isomers in cottonseed oil (study 1, 15 nmol/d; study 2, 30 nmol/d). In study 1, the βC isomers did not maintain baseline liver VA stores in all groups (0·69 (sd 0·20) μmol/liver) except in the VA+group (0·56 (sd 0·10) μmol/liver) ( P = 0·0026). The βC groups were similar to the VA+group, but the 9 c - and 13 c -βC groups did not differ from the VA − group (0·39 (sd 0·09) μmol/liver). In study 2, the βC isomers maintained baseline liver VA stores in all the βC groups (0·35 (sd 0·13) μmol/liver), and in the VA+group, the VA supplement (0·54 (sd 0·19) μmol/liver) exceeded the baseline VA status (0·38 (sd 0·15) μmol/liver) ( P < 0·0001); however, the 9 c -βC group did not differ from the VA − group (0·20 (sd 0·07) μmol/liver). In vivo isomerisation of βC was confirmed in both experimental studies. Lower VA bioconversion factor values were obtained for the cis -βC isomers in study 2 when compared with study 1, but higher values were obtained for the a t -βC isomer. Dose and VA status clearly affect bioconversion factors. In conclusion, the cis -βC isomers yielded similar liver VA stores to the a t -βC isomer in Mongolian gerbils, and liver VA stores of the 9 c - and 13 c -βC groups did not differ when the doses were provided at physiological levels over time in two studies.