ABSTRACT
Objectives: Previous studies evaluating the ability of fortified rice to improve hemoglobin and ferritin concentrations have produced mixed results. The literature indicates that combining iron (Fe) and zinc (Zn) can reduce the effects on iron status expected from iron supplementation alone. Our objective is to examine the relationship between the Fe/Zn molar ratio in fortified rice and improvements in hemoglobin and ferritin concentrations. Methods: Fe/Zn molar ratios of several fortified rice trials were examined in relation to changes in hemoglobin and serum ferritin concentration. The effect of exogenous zinc on iron solubilization of fortified rice was further evaluated using an in vitro assay to test fortified rice blends with known ratios of iron to zinc. Results: Although the fortified rice Fe/Zn ratios ranged from approximately 1 to 50, only in cases where the ratio exceeded 10 was a significant improvement in iron status (hemoglobin and/or ferritin) observed. The in vitro evaluation clearly associated exogenous zinc, in a dose-dependent manner, with inhibition of iron solubilization. Iron solubilized from fortified rice blends increased exponentially as the Fe/Zn ratio increased from 3.5 to 13.0. The plot of soluble iron vs. Fe/Zn further enabled prediction of the iron solubilization expected for any given Fe/Zn ratio. Conclusions: Iron fortification programs have the potential to significantly reduce iron deficiency anemia (IDA) and iron deficiency (ID). This research aimed to establish the relationship between the Fe/Zn molar ratio and health outcomes. Further research is needed to identify the most cost-effective Fe/Zn molar ratio to reduce IDA and/or ID. *Funded by USDA/FAS.