Zinc absorption in Guatemalan schoolchildren fed normal or low-phytate maize.
BACKGROUND
Poor bioavailability of zinc from high-phytate diets is an important contributory factor to zinc deficiency in low-income populations.


OBJECTIVE
The objective of this study was to determine the effect of low-phytate maize consumption on zinc absorption.


METHODS
The participants were apparently healthy children from the Central Highlands of Guatemala. Sixty children (20 per group) were randomly assigned to be fed only the low-phytate maize or 1 of 2 control maizes, the isohybrid wild-type maize or a local maize, for a 10-wk period. During the final week, the fractional absorption of zinc for all meals was measured during 1 d with the use of zinc stable isotopes and a dual isotope ratio technique based on urine enrichment data.


RESULTS
Mean (+/-SD) phytate intakes for the low-phytate, wild-type, and local maize groups were 1536 +/- 563, 2056 +/- 517, and 2253 +/- 687 mg/d, respectively. Corresponding zinc intakes were 8.6 +/- 2.5, 8.1 +/- 2.0, and 9.7 +/- 2.6 mg/d, and the dietary phytate:zinc molar ratios were 18 +/- 5, 26 +/- 6, and 23 +/- 5. Corresponding fractional absorptions of zinc were 0.32 +/- 0.07, 0.28 +/- 0.07, and 0.29 +/- 0.06. The respective values for total absorbed zinc were 2.72 +/- 0.88, 2.30 +/- 0.96, and 2.78 +/- 1.04 mg/d. No significant differences in either the fractional absorption of zinc or total absorbed zinc were seen between the maize groups.


CONCLUSIONS
Under the conditions of the present study, zinc absorption was not increased by the long-term use of low-phytate maize in children whose major dietary staple is maize.
Mazariegos
Manolo
M
Center for Studies of Sensory Impairments, Aging, and Metabolism, Guatemala City, Guatemala. manolomazariegos@yahoo.es
Hambidge
K Michael
KM
Krebs
Nancy F
NF
Westcott
Jamie E
JE
Lei
Sian
S
Grunwald
Gary K
GK
Campos
Raquel
R
Barahona
Brenda
B
Raboy
Victor
V
Solomons
Noel W
NW
D000886:Anthropometry; D001682:Biological Availability; D002648:Child; D003430:Cross-Sectional Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D030841:Food, Genetically Modified; D006166:Guatemala; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects; D008297:Male; D009752:Nutritional Status; D010833:Phytic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D030821:Plants, Genetically Modified; D003313:Zea mays / Q000737:chemistry* / Q000235:genetics; D015032:Zinc / Q000008:administration & dosage* / Q000172:deficiency / Q000493:pharmacokinetics*; D015033:Zinc Isotopes / Q000493:pharmacokinetics
D015033:Zinc Isotopes; D010833:Phytic Acid; D015032:Zinc