In people with thyroid diseases, higher levels of TSH in the blood are linked to lower amounts of iodine, selenium, and zinc in the thyroid tissue, indicating that thyroid function may be related to the balance of these trace elements.

In patients with mild deficiencies of iodine and selenium, the levels of these elements in thyroid tissue change in ways that relate to the amount of thyroid-stimulating hormone present, suggesting that nutrient levels and thyroid activity are linked in diseased tissue.

In people with thyroid disease, the levels of iodine, selenium, and zinc in thyroid tissue are typically within the range seen in earlier studies, even though the general population may have slightly low levels of iodine and selenium.

Taking selenium supplements does not change the levels of thyroid-stimulating hormone (TSH) in adults with chronic autoimmune thyroiditis, whether or not they are taking levothyroxine.

When someone has Graves’ disease, their thyroid hormones get too high, which tells the brain to stop making a hormone that stimulates the thyroid — so that hormone ends up being very low or even missing in blood tests.

In people with mild thyroid dysfunction, a higher ratio of TSH to free T4 hormone levels is linked to thyroid nodules that appear more solid on ultrasound scans.