Malnutrition is an enormous problem throughout the world.  Although it is often a result of poverty, frequently it also results from environmental problems.  Such problems can, for example, impair a family's capacity to produce food as a result of land degradation, water salinity, over-irrigation, soil erosion, droughts, and flooding.  These conditions may lead to widespread malnutrition. Malnutrition can take a serious toll on human health.  In fact, it is estimated that malnutrition from all causes was responsible for twelve percent of all deaths worldwide in 1990.

There are many sorts of deficiencies resulting from malnutrition.  These include iron, iodine, and vitamin A deficiencies, as well as the specific protein-energy malnutrition.  Soil characteristics can play a large part in the development of these deficiencies by influencing which nutrients are present in the food of a region. Mountainous regions are known for iodine deficiencies; areas with weather extremes, such as arid, infertile, or wet, humid land, can be deficient in vitamin A; and many parts of Africa, South America and Asia suffer from protein-energy malnutrition, as well as all three deficiency types, due to various environmental conditions.

Each deficiency causes its own range of health problems.  Iron deficiencies are known as anemia.  This can cause hemorrhaging in instances such as childbirth, as well as physical productivity reductions. They can also undermine childrens' learning capacity. Vitamin A deficiencies can cause loss of eyesight, ranging from deteriorating night vision to complete blindness.  Many persons blinded die within the following year.  Lack of iodine is a leading worldwide cause of brain damage and mental retardation.  Iodine deficiencies can also lead to iodine deficiency disorders and goiter, or enlargement of the thyroid gland.  In pregnant women, this deficiency can cause brain damage in the developing fetus.

Protein-energy malnutrition can do harm to the immune system, making it difficult for affected children to combat potentially damaging diseases, such as tuberculosis and malaria.  Such diseases can worsen the deficiencies.  Malnutrition can also heighten the effect of toxic chemicals on humans, and various deficiencies can influence the body's absorption of substances such as lead, leading to more dangerous health hazards.

A UNICEF report on malnutrition

Video of women in Niger fighting malnutrition