Bioavailability to rats of iron in six varieties of wheat grain intrinsically labeled with radioiron

Abstract

Bioavailability to anemic rats of iron in six varieties of wheat grain was assessed by a whole-body radioassay procedure. Intrinsically labeled kernels were harvested from plants grown in 59Fe-labeled nutrient solutions. The varieties used were selected from 18 varieties of field-grown wheat grain that were analyzed for iron, protein and phytate content. Concentrations of iron, phytate and protein in grain of field-grown varieties ranged from 34 to 55 ppm, 0.7 to 1.2% dry wt and 11.3 to 15.4% dry wt, respectively. In grain from varieties grown in nutrient solutions, iron, phytate and protein concentrations ranged from 35 to 50 ppm, 1 to 1.2% dry wt, and 13.8 to 16.8% dry wt, respectively. Depending on the variety of intrinsically labeled grain fed in test meals to anemic rats (hemoglobin averaged 5.8 g/dL), absorption of 59Fe ranged from about 62 to 74% of the dose; differences among varieties were not significant (P greater than 0.05). Rats fed 59Fe-labeled FeCl3 absorbed about 71% of the dose, which was similar to the average amount (69% of dose) absorbed by rats fed wheat. We concluded that selection of wheat varieties for increased yield or protein content has not adversely affected the bioavailability of iron in the grain.