Global distribution and disease burden related to micronutrient deficiencies.

Micronutrients are vitamins and minerals that are essential for human life and health. Deficiencies in these micronutrients are common because of poor quality diets and frequent infectious diseases in low- and middle-income countries. The high prevalence of deficiencies and their important adverse consequences on mortality, morbidity and disability result in a substantial disease burden. In particular, deficiencies of vitamin A and zinc increase the risk of child mortality, and zinc deficiency increases infectious morbidity and reduces linear growth as well. Deficiencies of iodine and iron are significant primarily for their effects on development and cognition and consequent disabilities. Programs targeting each of these micronutrients are underway and, particularly for vitamin A and iodine, have some success. Greater efforts to address these and the full set of micronutrients are needed to reduce their global burden of diseases.