Zinc absorption from biofortified maize meets the requirements of young rural Zambian children.
BACKGROUND
The zinc content of maize, a major global food staple, is generally insufficient alone to meet the requirements of young children.


OBJECTIVE
The primary objective of this study was to determine whether substitution of biofortified maize (34 μg zinc/g grain) for control maize (21 μg zinc/g) was adequate to meet zinc physiologic requirements in young children for whom maize was the major food staple. A secondary objective was to compare total daily zinc absorption when maize flour was fortified with zinc oxide to a total concentration of 60 μg zinc/g.


METHODS
Participants included 60 rural Zambian children with a mean age of 29 mo who were randomly assigned to receive 1 of 3 maize types (control, biofortified, or fortified) all of which were readily consumed (>100 g on 1 d). Total daily zinc intake (from maize and low-zinc relish) was determined from duplicate diet collections. Multiplication by fractional absorption of zinc, measured by a dual isotope ratio technique, determined the total daily zinc absorption on the day the test meals were given.


RESULTS
The mean ± SD total daily zinc intake (milligrams per day) from the biofortified maize (5.0 ± 2.2) was higher (P < 0.0001) than for the control maize (2.3 ± 0.9). Intake of zinc from the fortified maize (6.3 ± 2.6) did not differ from the biofortified maize. Fractional absorption of zinc from control maize (0.28 ± 0.10) did not differ from the biofortified maize (0.22 ± 0.06). Total daily absorption of zinc (milligrams per day) from the biofortified maize (1.1 ± 0.5) was higher (P = 0.0001) than for the control maize (0.6 ± 0.2), but did not differ from the fortified maize (1.2 ± 0.4).


CONCLUSIONS
These results indicate that feeding biofortified maize can meet zinc requirements and provide an effective dietary alternative to regular maize for this vulnerable population. This trial was registered at clinicaltrials.gov as NCT02208635.
University Teaching Hospital, Lusaka, Zambia;
Elwyn
E
Chomba
Section of Nutrition, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO; and.
Claire M
CM
Westcott
Section of Nutrition, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO; and.
Jamie E
JE
Westcott
University Teaching Hospital, Lusaka, Zambia;
Evans M
EM
Mpabalwani
Section of Nutrition, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO; and.
Nancy F
NF
Krebs
Section of Nutrition, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO; and.
Zachary W
ZW
Patinkin
International Maize and Wheat Improvement Center, Mexico City, Mexico.
Natalia
N
Palacios
Section of Nutrition, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO; and Michael.Hambidge@ucdenver.edu.
K Michael
KM
Hambidge
D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D003430:Cross-Sectional Studies; D004032:Diet; D005433:Flour / Q000032:analysis; D005527:Food, Fortified; D012424:Rural Population; D003313:Zea mays / Q000737:chemistry; D015032:Zinc / Q000008:administration & dosage / Q000493:pharmacokinetics
D015032:Zinc
Zambia; biofortification; fortified; maize; physiologic zinc requirement; young children; zinc absorption