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The thyroid gland is an endocrine organ whose hormones enable the proper
functioning of the organism. The normal function of this organ is influenced by internal and
external factors. One of the external factors is trace elements. Trace elements in appropriate
concentrations are necessary for the proper functioning of the thyroid. Fe, Cu, Mn, I, Zn,
and Se are part of the enzymes involved in oxidative stress reduction, while Cd, Hg, and
Pb can increase ROS production. Cu and Fe are necessary for the correct TPO synthesis. An
imbalance in the concentration of trace elements such as Fe, Cu, Co, I, Mn, Zn, Ag, Cd, Hg,
Pb, and Se in thyroid cells can lead to thyroid diseases such as Graves’ disease, Hashimoto’s
thyroiditis, hypothyroidism, autoimmune thyroiditis, thyroid nodules, thyroid cancer, and
postpartum thyroiditis. Lack of adequate Fe levels may lead to hypothyroidism and
cancer development. The thyroid gland’s ability to absorb I is reversibly reduced by Co.
Adequate levels of I are required for correct thyroid function; both deficiency and excess
can predispose to the development of thyroid disorders. High concentrations of Mn may
lead to hypothyroidism. Furthermore, Mn may cause cancer development and progression.
Insufficient Zn supplementation causes hypothyroidism and thyroid nodule development.
Cd affecting molecular mechanisms may also lead to thyroid disorders. Hg accumulating
in the thyroid may interfere with hormone secretion and stimulate cancer cell proliferation.
A higher risk of thyroid nodules, cancer, autoimmune thyroiditis, and hypothyroidism
were linked to elevated Pb levels. Se deficiency disrupts thyroid cell function and may lead
to several thyroid disorders. On the other hand, some of the trace elements may be useful
in the treatment of thyroid diseases. Therefore, the effects of trace elements on the thyroid
require further research.
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