Role of Micronutrients

Micronutrients are vitamins and minerals that all humans need to maintain strong bodies and mental sharpness, fight off disease, and bear healthy children. Micronutrient deficiency is caused by inadequate access to micronutrient-rich food, high burden of infection and parasites, and detrimental feeding and dietary practices. Micronutrient deficiency adversely affects the health and function of individuals and the economic and social development of communities and nations. Vitamin A, iron, iodine, zinc, and folate among others profoundly affect child survival, women’s health, educational achievement, adult productivity, and overall resistance to illness.

Vitamin A

Vitamin A is essential for optimal health, growth, and development. Vitamin A deficiency is a major underlying determinant of child mortality and blindness in the developing world. It causes xerophthalmia, a serious eye disorder that can lead to blindness if untreated. In children, vitamin A deficiency compromises the immune system, increasing the risk of severe illness and death from diarrheal diseases and other infections, such as measles. Vitamin A comes in two forms: one from animal sources and the other from plants. Absorption is greater from animal sources. Deficiency is the result of insufficient intake of animal sources of vitamin A and low absorption of plant sources often due to inadequate fat or oil in the diet.


Iron is essential for good health and mental and physical well-being. Iron deficiency anemia occurs when the body's iron supply cannot support the production of hemoglobin in adequate amounts to carry enough oxygen from the lungs to the muscles, brain, and other tissues. This causes weakness, fatigue, and reduced physical ability to work. Among adults it reduces work productivity. Anemia resulting from iron deficiency or other causes reduces a woman’s ability to survive bleeding during and after childbirth and may result in premature and/or low birth weight babies with a higher risk of death. Iron deficiency in children slows intellectual and motor development. The main causes of iron deficiency are low consumption of meat, fish, or poultry or the presence of inhibitors in the diet that prevent iron from being absorbed. In resource-poor areas, anemia is commonly caused by infectious diseases such as malaria, hookworm, and HIV/AIDS.  


Iodine, a mineral present in soil and water, is essential to normal and healthy functioning of the thyroid. Iodine deficiency is the most common cause of preventable brain damage in the world today. Iodine deficiency during pregnancy can cause stillbirths, spontaneous abortions, low birth weight, and congenital abnormalities such as cretinism and goiter (enlarged thyroid). Iodine deficiency in children leads to lower IQ. Iodine cannot be stored in the body for long periods, so tiny amounts are needed regularly. Iodine deficiency disorders can result from low iodine in the soil and therefore in crops and grazing animals. Iodized salt is the most common intervention to prevent iodine deficiency disorders.


Zinc is an essential element that promotes healthy immune system functioning and protects against infectious diseases. Adequate zinc nutrition is necessary for optimal child health and survival, physical growth, and for a normal pregnancy. Zinc deficiency in children results in increased risk of diarrhea, pneumonia, and malaria. Zinc is important in the treatment of diarrhea in children. Limited access to zinc-rich foods, such as animal products and shellfish, and inadequate absorption of zinc cause zinc deficiency. 


Folate is a vitamin essential in the production and maintenance of new cells. It is particularly important during periods of rapid cell division and growth such as the fetal period and infancy. The synthetic form of folate is folic acid. The risk of neural tube defects is significantly reduced if a woman increases her folic acid intake through either fortification or supplementation prior to and during early pregnancy. Nutritional deficiency of folate is common in people consuming a highly refined, unfortified diet or one lacking in diversity.

Multiple Micronutrients

Good health requires the presence of numerous micronutrients. For example, vitamin C and vitamin A are needed for intestinal iron absorption. Adequate amounts of folate, vitamin B-2, vitamin B-6, and vitamin B-12 are essential for the synthesis of red blood cells. Public health experts are becoming increasingly aware that populations deficient in one vitamin or mineral are usually deficient in other micronutrients as well. Governments, agencies, and others are expected in the future to document and address such multiple micronutrient deficiencies using more comprehensive strategies.