|CHANG, JASMINE - University Of California|
Submitted to: British Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/26/2010
Publication Date: 1/20/2011
Citation: Burri, B.J., Chang, J., Neidlinger, T.R. 2011. Beta-Cryptoxanthin- and alpha-carotene-rich foods have greater apparent bioavailability than beta-carotene-rich foods in Western diets. British Journal of Nutrition. 105:212-219.
Interpretive Summary: Beta-carotene (BC), beta-cryptoxanthin (CX) and alpha-carotene (AC) are common phytonutrients that form vitamin A (VA). Conversion ratios for VA formation have been set at 12:1 for BC, but 24:1 for CX- and AC-rich foods. Our objective was to compare concentrations of AC, BC, and CX in blood with their dietary intakes. This will allow us to estimate their bioavailability from food. Results show that eating comparable amounts of AC- and BC- rich foods would result in 1.5-fold greater AC plasma concentrations. Even more remarkably, eating comparable amounts of CX- and BC-rich foods would result in 15-fold higher CX plasma concentrations. This may mean that the bioavailability of AC and especially CX from their main food sources is higher than that of BC. In turn, this may mean that CX-rich foods (such as mandarin oranges and papaya) might be better sources of VA than expected. The formation of VA from AC and CX deserves further study.
Technical Abstract: Background: Beta-carotene (BC), beta-cryptoxanthin (CX) and alpha-carotene (AC) are common carotenoids that form vitamin A (VA). Conversion ratios for VA formation have been set at 12:1 for BC- and 24:1 for CX- and AC-rich foods, respectively. These conversion ratios are based on chemical structure, assuming that equivalent amounts of dietary AC-, BC-, and CX yield equivalent blood concentrations, and that these carotenoids have similar bioavailability. Objective: To associate concentrations of AC, BC, and CX in blood with their dietary intakes, thus comparing their bioavailability from food. Design: Dietary intakes were estimated by food frequency questionnaire (4 studies this laboratory, n = 116; ratios calculated for 8 other studies, n = 2340) or by food record (2 studies this laboratory, n = 59; ratios for 2 other studies, n = 118). Carotenoid concentrations were measured by reversed-phase HPLC. The ratio of dietary intake (d) to blood concentration (b) for AC, BC, and CX, was calculated, then ratios of ACb/d /BC b/d and CX b/d/BC b/d. Results: ACb/d/BCb/d was 1.5 (99% confidence 1.21-1.77), CXb/d/BCb/d was 15 (99% confidence 8.39 – 21.7). Thus, eating comparable amounts of AC-, CX and BC-rich foods would result in 1.5-fold greater AC and 15-fold greater plasma concentrations of CX plasma concentrations. Conclusions: This suggests that bioavailabilities of AC and especially CX from their main food sources are greater than that of BC, and thus AC and especially CX-rich foods might be better sources of VA than expected. The formation of VA from AC and CX deserves further study.