Zinc absorption from a low-phytic acid maize.
BACKGROUND
Phytic acid reduction in cereal grains has been accomplished with plant genetic techniques. These low-phytic acid grains provide a strategy for improving the mineral (eg, zinc) status in populations that are dependent on grains, including maize (Zea mays L.), as major dietary staples.


OBJECTIVE
The objective was to compare the fractional absorption of zinc from polenta prepared from maize low in phytic acid with that prepared from a wild-type isohybrid maize (control) after short-term consumption by adults whose habitual diet is low in phytic acid.


METHODS
Healthy adults served as their own control subjects in a crossover design. All meals on 1 d consisted of polenta prepared from a low-phytic acid maize homozygous for the recessive low phytic acid 1-1 (lpa1-1). On the preceding or following day, all meals consisted of polenta prepared from a sibling isohybrid homozygous wild-type maize with a "normal" phytic acid content. The low-phytic acid maize contained approximately 60% less phytic acid than did the wild-type maize. All test meals were extrinsically labeled with zinc stable-isotope tracers. The fractional absorption of zinc was determined on the basis of fecal enrichment.


RESULTS
The molar ratios of phytic acid to zinc in the polenta prepared from lpa1-1 maize and the wild-type maize were 17:1 and 36:1, respectively. The corresponding fractional absorptions of zinc were 0.30 +/- 0.13 and 0.17 +/- 0.11, respectively (P < 0.005).


CONCLUSIONS
Substitution of a low-phytic acid grain in a maize-based diet is associated with a substantial increase in zinc absorption.
Adams
Christina L
CL
Section of Nutrition, Department of Pediatrics, University of Colorado Health Sciences Center, Denver 80220, USA.
Hambidge
Michael
M
Raboy
Victor
V
Dorsch
John A
JA
Sian
Lei
L
Westcott
Jamie L
JL
Krebs
Nancy F
NF
D000042:Absorption; D000328:Adult; D001682:Biological Availability; D018592:Cross-Over Studies; D004032:Diet; D005243:Feces / Q000737:chemistry; D005260:Female; D005818:Genetic Engineering; D006801:Humans; D008297:Male; D010833:Phytic Acid / Q000032:analysis*; D003313:Zea mays / Q000737:chemistry* / Q000235:genetics; D015032:Zinc / Q000008:administration & dosage / Q000493:pharmacokinetics*; D015033:Zinc Isotopes
D015033:Zinc Isotopes; D010833:Phytic Acid; D015032:Zinc