There are five micronutrients of which deficiencies are considered as a major public health problem, especially in low and middle-income countries:
- Iron is needed to make haemoglobin, the protein in red blood cells that carries oxygen to the tissues. It allows the muscles and brain to work properly. Iron deficiency can result in anemia, a lack of haemoglobin in the blood that causes fatigue and other health problems.
- Vitamin A is needed to prevent infection and to keep the immune system working properly. It keeps the skin, eyes and lining of the gut and lungs healthy and helps to see in dim light. Vitamin A deficiency can result in night blindness, blindness, disease and death.
- Iodine is needed to make thyroid hormones that help to control the way the body works. Iodine is essential for the development of the brain and nervous system in the foetus. Iodine is often added to salt. Iodine deficiency can result in goiter and cretinism.
- Folate is needed to make healthy red blood cells. If a woman is deficient in pregnancy this can result in severe abnormalities in the foetus like Spina bifida.
- Zinc is needed for growth and normal development, for reproduction and to keep the immune system working properly. Zinc deficiency is associated to stunting and plays a role in diarrheal diseases.
In Western countries micronutrient deficiencies are less common, partly because of a more diverse diet, partly because of government-led supplementation and fortification programmes. However, deficiencies still exist but are not a wide-spread public health problem. Certain groups of the population have a higher risk for certain micronutrient deficiencies, like pregnant women, elderly and sick people.
Double/triple burden of malnutrition: In low and middle-Income countries, undernutrition, overweight and obesity can co-exist in the same country, community, family or individual. We call this the double burden of malnutrition. We can even speak of a triple burden of malnutrition, because undernutrition, overweight and obesity and micronutrient deficiencies can also co-exist.