Maize Milling Method Affects Growth and Zinc Status but Not Provitamin A Carotenoid Bioefficacy in Male Mongolian Gerbils.
Background:Vitamin A (VA) and zinc deficiencies are prevalent. Maize is a common staple, and milling affects nutrient and nutrient-modifier profiles.Objective:We investigated the interaction of maize milling methods (i.e., whole grain compared with refined) in male Mongolian gerbils aged 29-35 d with conventionally bred provitamin A-biofortified (orange) or white maize on VA and zinc status.Methods:Study 1 (n= 67) was a 2 × 3 milling (whole compared with refined) by VA [no-vitamin A placebo group (VA-), orange, and VA-supplemented group (VA+)] design, with 4 wk of VA depletion followed by six 4-wk treatments (n= 10/treatment). Study 2 (n= 33) was a 2 × 2 milling-by-zinc [no-zinc placebo group (Zn-) compared with zinc-supplemented group (Zn+)] design, including 2 wk of VA depletion followed by four 3-wk treatments (n= 8-9/treatment). For study 1, positive and negative control groups were given supplemental VA at equimolar amounts to β-carotene equivalents consumed by the orange groups (74 ± 5 nmol/d) or placebo, respectively. For study 2, positive and negative control groups were given 152 μg Zn/d or placebo, respectively.Results:Milling significantly affected zinc concentration, providing 44-45% (whole grain) or 9-14% (refined) NRC requirements. In study 1, orange maize improved liver VA concentrations (mean ± SD: 0.28 ± 0.08 μmol/g) compared with the white maize groups (0.072 ± 0.054 μmol/g). Provitamin A bioefficacy was similar. In study 2, neither zinc nor milling influenced liver retinol. Refined Zn- gerbils weighed less than others by day 14 (46.6 ± 7.1 compared with 56.5 ± 3.5 g, respectively;P< 0.0001). Milling affected pancreas zinc concentrations (refined Zn-: 21.1 ± 1.8 μg Zn/g; whole Zn-: 32.5 ± 5.8 μg Zn/g).Conclusions:Whole-grain intake improved zinc and did not affect provitamin A bioefficacy. Other factors affected by milling (e.g., shelf life, preference, aflatoxin fractioning) need to be considered to maximize health.
Interdepartmental Graduate Program in Nutritional Sciences, Department of Nutritional Sciences, and.
Bryan M
0000-0003-1781-9242
BM
Gannon
Department of Agronomy, University of Wisconsin-Madison, Madison, WI; and.|International Maize and Wheat Improvement Center, Texcoco, Mexico.
Kevin V
KV
Pixley
Interdepartmental Graduate Program in Nutritional Sciences, Department of Nutritional Sciences, and sherry@nutrisci.wisc.edu.
Sherry A
SA
Tanumihardjo
D000821:Animal Feed / Q000032:analysis; D000818:Animals; D004032:Diet / Q000662:veterinary; D005511:Food Handling / Q000379:methods*; D005527:Food, Fortified; D005849:Gerbillinae; D008099:Liver / Q000378:metabolism; D008297:Male; D009752:Nutritional Status; D014801:Vitamin A / Q000378:metabolism; D003313:Zea mays / Q000737:chemistry* / Q000378:metabolism; D015032:Zinc / Q000097:blood / Q000378:metabolism*; D019207:beta Carotene / Q000008:administration & dosage* / Q000032:analysis / Q000378:metabolism
D019207:beta Carotene; D014801:Vitamin A; D015032:Zinc
bioconversion; iron; pancreas; retinol; vitamin A