Effect of genetically modified, low-phytic acid maize on absorption of iron from tortillas.
BACKGROUND
Genetically modified, low-phytic acid strains of maize were developed to enhance mineral absorption, but have not been tested previously in humans.


OBJECTIVE
We evaluated the mineral and phytic acid contents of a low-phytic acid "flint" maize (LPM, the lpa-1-1 mutant) and its parent, wild-type strain (WTM) and measured iron absorption from tortillas prepared with each type of maize and from a reference dose of ferrous ascorbate.


METHODS
Proximate composition and mineral and phytic acid contents were measured by standard techniques. Iron absorption from tortillas was evaluated by using the extrinsic tag method and was measured as the incorporation of radiolabeled iron into the red blood cells of 14 nonanemic men 2 wk after intake.


RESULTS
The phytic acid content of LPM was 3.48 mg/g, approximately 35% of the phytic acid content of WTM; concentrations of macronutrients and most minerals were not significantly different between strains. Iron absorption results were adjusted to 40% absorption of ferrous ascorbate. Iron absorption was 49% greater from LPM (8.2% of intake) than from WTM (5.5% of intake) tortillas (P < 0.001, repeated-measures analysis of variance).


CONCLUSIONS
Consumption of genetically modified, low-phytic acid strains of maize may improve iron absorption in human populations that consume maize-based diets.
Mendoza
C
C
Institute of Nutrition of Central America and Panama, Guatemala City, Guatemala. cmendoza@ucdavis.edu
Viteri
F E
FE
Lönnerdal
B
B
Young
K A
KA
Raboy
V
V
Brown
K H
KH
D000328:Adult; D000704:Analysis of Variance; D005511:Food Handling; D006801:Humans; D007295:Inositol Phosphates / Q000032:analysis; D007408:Intestinal Absorption / Q000187:drug effects; D007501:Iron / Q000493:pharmacokinetics*; D000090463:Iron Deficiencies; D008297:Male; D010833:Phytic Acid / Q000008:administration & dosage / Q000032:analysis / Q000494:pharmacology*; D003313:Zea mays / Q000737:chemistry / Q000235:genetics*
D007295:Inositol Phosphates; D010833:Phytic Acid; D007501:Iron