Risk, lesser developed countries

Globally, almost two billion people (one-third of the human race) are affected by vitamin A, iron, iodine, and/or zinc deficiencies that put them at an increased risk of poor growth, morbidity, intellectual impairment, and/or mortality. Since the mid-1980s micronutrient supplementation has been a major public-health strategy in developing countries to prevent and control deficiencies in vitamin A, iron, and, to a lesser extent, iodine. More recently, zinc supplementation has come to be considered as an efficacious adjunctive therapy for diarrhea in populations with an elevated risk of zinc deficiency. This article will define micronutrient supplementation, examine the role of supplementation as a strategy for the prevention and control of micronutrient deficiencies, and examine evidence for vitamin A, iron, iodine, and zinc supplementation interventions with respect to efficacy, recommended dose, frequency of administration, safety, and program effectiveness. 

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