The importance of iodine as an essential element arises from the fact that it is a constituent of the thyroid hormones thyroxine and triiodothyronine.
These hormones are essential for normal growth and physical and mental development in animals and man.
Iodine deficiency occurs worldwide and is a public health problem in 130 countries.
Deficiency arise when dietary iodine intake does not meet requirements. The diet is likely to be deficient whenever the soil content of iodine is low, which is often the case in mountainous regions.
The most severe deficient soils are those of the European Alps, the Himalayas, the Andes and the vast mountains of China.
Iodine deficiency leads to inadequate production of thyroid hormone that indispensible for brain growth and development.
The iodine deficiency disorders consist of wide spectrum, including mental retardation, impaired physical development, increased prenatal and infant mortality, hypothyroidism, cretinism and goiter.
The most visible manifestation of iodine deficiency is goiter. Goiter is defined as an enlargement of the thyroid gland and cretinism is a term used for a severe form of iodine deficiency characterized by severe mental retardation.
The most severe damage due to iodine deficiency occurs from the fetal period to the third month after birth, during which iodine deficiency can produce cretinism, an irreversible form of mental retardation.
Iodine deficiency disorder