When poverty limits an adequate and varied diet, deficiencies of iron, iodine, and vitamin A often occur simultaneously with protein-energy malnutrition. Geography and soil characteristics also influence the amount of these nutrients commonly found in food. Africa, the Andean region of South America, and many parts of Asia are at risk from not only protein energy malnutrition, but also from all three main micronutrient deficiencies because of both poverty and environmental factors. Iron deficiency is the most common micronutrient disorder. The problem is most severe in India, where 88 percent of pregnant women are anemic.
Anemia increases the risk of death from hemorrhage in childbirth.
Globally, some 42 million children under age 6 have mild to moderate vitamin A deficiency. Up to 3 million more children suffer lesser but still serious effects, such as loss of night vision. Iodine deficiency is the world's leading single cause of preventable brain damage and mental retardation. Where this deficiency is endemic, the entire population may be affected, with different symptoms appearing in different age groups. The combination of malnutrition and infectious disease can be particularly pernicious.