Iron deficiency affects a large proportion of children and women in the developing world and is one of the most common nutrition disorders; the only nutrient deficiency of significant prevalence in virtu- ally all developed countries. Iron exists in two oxidation states, either Fe2+, the ferrous form, or Fe3+, the ferric form. Iron changes between these forms, enabling it to serve as a catalyst in redox reactions by donating or accepting electrons. The burden and causes of iron deficiency are well established, the challenge remains for the adequate prevention and control of iron deficiency.
Discussion .
Anemia is a commonly used indicator to screen for iron deficiency or to define the burden of iron deficiency in population-based surveys. There is a close association between anemia and iron deficiency. Iron deficiency is the most common cause of anemia in most parts of the world. Iron deficiency anemia represents the severe end of the spectrum of iron deficiency and requires the fulfillment of both the definition of anemia and iron deficiency. Iron deficiency without anemia represents a moderate form of iron deficiency in which iron-dependent function is impaired, but anemia is not present; anemia is defined as hemoglobin concentration below −2 standard deviations of the age and sex-specific normal reference. .
The World Health Organization estimated that about 4–5 billion people are iron deficient worldwide. Young children and women of reproductive age are at greatest risk, followed by the elderly and men. Although progress has been made in the reduction of anemia in parts of Central and South America, the rates continue to be high in countries such as Peru, Bolivia, and Haiti. Although not all anemias are caused by iron deficiency, in areas where the prevalence of anemia exceeds 30–40%, most anemia is caused in part or in total by iron deficiency. The estimated prevalence of iron deficiency for this childhood population would be 40–60%.