*4.4.4 Iodine*

Iodine (I) is needed for the synthesis of thyroid hormones which are involved in the growth, development and control of metabolic processes. Deficiency of iodine during early development of the brain and nervous system leads to cretinism, which is irreversible. At an older age, it leads to hypothyroidism and goiter, the first endemic disease that has been attributed to environmental factors. Marine fish and shellfish are foods particularly rich in iodine [37, 45].

### *4.4.5 Selenium*

Selenium (Se) is a component of the amino acid selenocysteine. Enzymes that depend on selenium play a very important role in cells. They offer protection against oxidative damage, modulation of growth and development as well as defense against infection. In humans, selenium deficiency can cause endemic cardiomyopathy known as "Keshan disease", which mainly affects children and women of childbearing age. Liver, kidney and seafood are particularly rich in selenium [36, 46].
