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Biofortification to increase provitamin A carotenoids is an agronomic approach to alleviate vitamin A deficiency. Two studies compared biofortified foods using in vitro and in vivo methods. Study 1 screened maize genotypes (n = 44) using in vitro analysis, which demonstrated decreasing micellarization with increasing provitamin A. Thereafter, seven 50% biofortified maize feeds that hypothesized a one-to-one equivalency between β-cryptoxanthin and β-carotene were fed to Mongolian gerbils. Total liver retinol differed among the maize groups (P = 0.0043). Study 2 assessed provitamin A bioefficacy from 0.5% high-carotene carrots added to 60% staple-food feeds, followed by in vitro screening. Liver retinol was highest in the potato and banana groups, maize group retinol did not differ from baseline, and all treatments differed from control (P < 0.0001). In conclusion, β-cryptoxanthin and β-carotene have similar bioefficacy; meal matrix effects influence provitamin A absorption from carrot; and in vitro micellarization does not predict bioefficacy.

Purple carrots contain anthocyanins in addition to the provitamin A carotenoids in typical orange carrots. Simultaneous consumption of these phytochemicals in carrots may affect the bioavailability of carotenoids. The bioavailability of beta-carotene in humans was assessed from an acute feeding of orange (OC) and purple (PC) carrots with white (WC) as a control. Carrot smoothies were served to female subjects (n = 5, aged 21-26 years) for breakfast after 1 week on a low carotenoid diet and overnight fast. OC and PC smoothies were equalized to 10.3 mg of all-trans beta-carotene. Plasma beta-carotene was measured for 144 h following treatments. Peak plasma concentrations of OC and PC treatments did not differ. The PC treatment 0-144 h area-under-the-curve for beta-carotene was 76% of the OC treatment (P < 0.05). However, when the first 24 h were compared, OC and PC treatments did not differ, suggesting that anthocyanins in purple carrots do not affect the absorption of beta-carotene postprandially.