Most trials examining the impact of micronutrient powders on anemia and iron status have been efficacy studies where variables were controlled and the interventions were closely supervised. A meta-analysis of efficacy trials demonstrated that Sprinkles, a micronutrient powder, were as effective as iron drops and had fewer adverse effects.1 In the prevention trials, the risk for anemia was cut in half.
The trial by Jack et al2 was somewhat unique in that it was designed as an effectiveness trial. Its goal was to determine whether Sprinkles could be successfully delivered to a free-living population of infants through an existing government health service in Cambodia. The trial compared nutrition education alone with the combination of nutrition education and micronutrient powder on nutritional outcomes including anemia status, zinc and vitamin A levels, and anthropometry in infants, starting at 6 months of age. The nutrition education was quite intensive and took the form of verbal and written instructions, pictures, and cooking demonstrations based on Cambodian foods and nutrition recommendations for infants at 6 months of age. All subjects were followed up monthly for 6 months. The results were quite conclusive and not surprising. Nutrition education alone, even when intensively communicated and clearly demonstrated, was inferior to the same nutrition education combined with micronutrient powders in terms of its impact on anemia status in infants between 6 and 11 months of age. When age-appropriate infant foods are fortified, in this case through home fortification with micronutrient powder containing iron, iron status and anemia rates were improved. This is not surprising because we know that human milk is not a good source of iron (20-40 μg/dL; to convert to micromoles per liter, multiply by 0.179), and we know that even if an infant is born at full term with a full endowment of stored iron, by 6 to 9 months of age, the iron will be incorporated into hemoglobin until stores are totally depleted, at which time anemia will become apparent.3 Multiple studies in developing and developed countries have demonstrated higher rates of iron depletion in longer vs shorter duration of exclusive breastfeeding.