Tuesday, November 14, 2006 - 3:00 PM
148-7
Carotenoid-Biofortified Maize Maintains Adequate Vitamin A Status in Mongolian Gerbils.
In many areas of the world, vitamin A (VA) deficiency is a major health problem. Staple foods such as maize, rice, and wheat, are typically low in provitamin A. Recent efforts to genetically improve maize with provitamin A carotenoids, e.g., β-carotene, have been successful, but whether this approach alleviates VA deficiency is unknown. Two studies investigated the bioefficacy of provitamin A carotenoids from maize (Zea mays L.) and compared the effects of maize percentage and carotenoid content on VA status in VA-depleted Mongolian gerbils (Meriones unguiculatus). Four near-isogenic maize lines were used to prepare 6 feeds with variable maize and carotenoid compositions. To initiate VA-deficiency, gerbils were fed a white maize VA-free diet for 4 wk prior to treatment. In study 1, treatments (n = 10/group) included oil control, 60% high-β-carotene maize, and β-carotene or VA supplements (matched to high-β-carotene maize). In study 2, gerbils were fed 30% or 60% orange or yellow maize diets. After 4-wk, liver VA was determined using HPLC. For study 1, liver VA, compared with the high β-carotene maize group, was significantly higher in the VA group (P < 0.05), lower in the control (P < 0.05), but did not differ from the β-carotene group. Bioconversion was ~1.5 mol β-carotene to 1 mol VA. Liver β-carotene content was greater in the high-β-carotene maize group compared with the β-carotene supplement (P < 0.05). Study 2 showed an improvement in VA status with increasing β-carotene. Vitamin A status in gerbils receiving orange maize was greater than those receiving yellow maize, regardless of percent (P < 0.05). Biofortified maize adequately maintained VA status in this model and was as effective as β-carotene supplementation. The contribution of β-cryptoxanthin in maize to VA is currently being evaluated.
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