Provitamin A biofortification of staple crops may ameliorate vitamin A (VA) status in countries where deficiency is prevalent. To assess the VA impact of these crops, the unique bioefficacies of cis-isomers (formed during cooking) as compared to all-trans (at) β-carotene must be determined. We evaluated the VA efficacy of 9-cis (9c) and 13-cis (13c) isomers as compared with at β-carotene and VA-positive and negative control groups in VA-depleted Mongolian gerbils in two studies (Study 1, n = 56; Study 2, n = 57). Gerbils were fed a VA-deficient diet throughout the studies. A 4-wk depletion was followed by 3-wk (Study 1) or 4-wk (Study 2) treatment with 9c, 13c, or at β-carotene in cottonseed oil (Study 1, 8.06 μg/day; Study 2, 16.1 μg/day). In Study 1, no treatment group maintained baseline liver stores (0.70 ± 0.21 μmol/liver). at Liver stores (0.54 ± 0.15 μmol/liver) did not differ from the VA group (0.56 ± 0.10 μmol/liver) when fed 2:1, but did differ significantly from 13c (0.41 ± 0.14 μmol/liver) and 9c (0.44 ± 0.18 μmol/liver). As baseline liver reserves were not maintained in Study 1, the study was repeated at a higher dose and for an extended experimental period. HPLC analysis of carotenoid and retinol concentrations in liver, serum, kidney, spleen, testes, and lung samples from Study 2 is underway.
Bresnahan, K.; Davis, C.; Tanumihardjo, S. The relative vitamin A value of 9-cis and 13-cis &#946;-Carotene as compared to all-trans &#946;-Carotene in Mongolian gerbils. FASEB Journal (2013) 27 (Meeting Abstract Supplement) 38.4.