The thyroid gland is the largest endocrine gland in the body. In recent decades although there is an increase in the incidence of thyroid diseases, they often remain undiagnosed.
The role of selenium in the thyroid gland
Among the elements involved in the health and good functioning of the thyroid gland is selenium. The name of selenium derives from the Greek word “σελήνη”, which means moon, because when selenium melts, it gets a bright gray color, like the moon.
The thyroid is the organ with the highest concentration of selenium per gram, relative to the other tissues. The reason is that the thyroid expresses a series of selenoproteins, which are responsible for the conversion of thyroxine-T4 to triiodothyronine-T3. Lack of selenium leads to a decrease in thyroid hormone synthesis, resulting in increased levels of TSH. However, increased TSH production and conversion of T4 to T3, results in the production of hydrogen peroxide, which is not sufficiently metabolized and thus accumulates and causes damages to the thyroid.
In addition, certain selenoproteins have very important antioxidant properties, contributing to the antioxidant protection of the thyroid and reducing the oxidative damage caused by free radicals. Selenium is thought to be beneficial even in autoimmune thyroid diseases such as Hashimoto’s disease and Graves’s disease.
Sources and forms of selenium
Selenium intake is determined by the characteristics of the population, the diet and the geographical area. The main sources of selenium are meat, fish, pasta, rice, bread and cereals.
Selenium is available in various forms. Organic forms of selenium (selenomethionine and selenocysteine) are better absorbable, offering greater bioavailability (90%). For this reason, they are the form of choice for the treatment of the thyroiditis. On the contrary, inorganic forms (selenite and selenate) do not have such a high bioavailability (10%) and are inferior.
Recommended daily allowance
The recommended daily intake of selenium is 55mcg for both men and women over 18 years of age. The needs vary according to the stage of development, pregnancy or breastfeeding. Although selenium is necessary for the proper functioning of the thyroid, high doses of selenium have toxic effects on the body.
Maintaining normal levels of selenium is essential to maintain thyroid health even after thyroid disease has occurred. For selenium supplements, you can visit Vita4you.