Elemental iron powders are the most commonly used food fortificants worldwide because they are relatively inexpensive and do not compromise product flavor, color or shelf-life. However, research conducted over the last 45 years on the bioavailability of these powders has yielded highly variable results (from 5% to 145% relative to the standard ferrous sulfate). These discrepancies undermine confidence in the efficacy of various food-grade powders and have discouraged implementation of food enrichment programs worldwide.

Given the high prevalence of iron deficiency anemia in developing countries and the wide use of elemental iron powders in food fortification programs, a thorough evaluation of iron powders currently in use makes good sense. This, in fact, was one of the key recommendations to emerge from an international workshop which SUSTAIN convened in Monterrey, Mexico in 2000 to address decades of confusion over the efficacy of the powders. To help make sense of published data, SUSTAIN is preparing an in-depth review of research conducted on the bioavailability of elemental iron powders over the past 45 years. With funding from the Bill & Melinda Gates Foundation, we have also launched a major new research initiative to rigorously evaluate the bioavailability of each of the elemental iron powders now in use as food fortificants.

Initially each powder will be assessed in a series of metallurgic tests to characterize their structures and surface properties. Since no single screening method reliably predicts the efficiency of iron absorption in human subjects, SUSTAIN will evaluate the powders with all of the available screening methods. Consistency of results will point to the powders meriting further evaluations in human studies with a population of mildly iron-deficient volunteers. In these human trials, multiple biological indicators will be used to measure improvement in iron status over the 9-12 months participants consume iron-fortified diets. This evaluation of elemental iron powders should provide a firm basis for issuing recommendations on the use of elemental iron in food fortification to reduce iron deficiency anemia.

It may also provide industry with information manufacturers can use to improve the bioavailability characteristics of their powders. This, in turn, could accelerate the adoption of iron fortification practices in developing countries, leading to far reaching public health benefits.