Carotenoid-biofortified maize maintains adequate vitamin a status in Mongolian gerbils

Efforts to biofortify maize with provitamin A carotenoids have been successful, but the impact on vitamin A (VA) status has not been determined. We conducted two studies that investigated the bioefficacy of provitamin A carotenoids from maize and compared maize percentage and carotenoid concentrations on VA status in VA-depleted Mongolian gerbils (Meriones unguiculatus). Gerbils (n = 40/study) were fed a white maize diet 4 wk prior to treatment. In study 1, treatments (n = 10/group) included oil control, 60% high-beta-carotene maize, and beta-carotene or VA supplements (matched to high-beta-carotene maize). In study 2, gerbils were fed 30 or 60% orange or yellow maize diets. Gerbils were killed after 4 wk. In study 1, liver VA concentrations, compared with the high-beta-carotene maize group (0.25 +/- 0.15 micromol/g), were higher in the VA group (0.56 +/- 0.15 micromol/g, P < 0.05), lower in the control (0.10 +/- 0.04 micromol/g, P < 0.05), and did not differ in the beta-carotene group (0.25 +/- 0.08 micromol/g). Bioconversion was approximately 3 microg beta-carotene to 1 mug retinol (1.5 mol beta-carotene to 1 mol retinol). The liver beta-carotene content was greater in the high-beta-carotene maize group (26.4 +/- 6.0 nmol) than in the beta-carotene supplement group (14.1 +/- 6.0 nmol; P < 0.05). In study 2, the gerbils' VA status improved with increasing dietary beta-carotene. Liver VA in gerbils fed orange maize was greater than in those fed yellow maize, regardless of maize percentage (P < 0.05). Biofortified maize adequately maintained VA status in Mongolian gerbils and was as efficacious as beta-carotene supplementation. In populations consuming maize as a staple food, using orange instead of white maize could dramatically affect VA status.