Iodine and thyroid function

Abstract

Severe iodine deficiency causes hypothyroidism that results in impaired somatic growth and motor development in children. Mild and moderate iodine deficiencies cause multifocal autonomous growth of thyroid, which results in thyrotoxicosis. On the other hand, iodine excess is associated with the development of hypothyroidism and thyroid autoimmunity. In areas of iodine deficiency, a sudden increase in iodine intake is associated with transient hyperthyroidism. Recent studies demonstrated that long-term thyroid function of subjects who experienced both iodine deficiency and iodine excess during childhood tended to be abnormal despite optimization of their current iodine intake. Iodine status in the Korean Peninsula is very unique because people in the Republic of Korea have been shown to have predominantly excessive iodine levels, whereas the Democratic People's Republic of Korea is known to be an iodine-deficient area. Further research is warranted to verify the optimal ranges of iodine intake and to clarify the effects of iodine intake on thyroid disorders in the Korean Peninsula.

Inadequate and Excessive Urinary Iodine Concentration in School Age Girls and Women in Makueni, Eastern Kenya

“…UIC above 300 µg/l was observed in more than half of both SAG and WRAs. It is therefore important to note that both iodine deficiency and iodine excess are associated with an increased risk of thyroid disorders [11].…”

“…Excessive iodine intake on the other hand can alter thyroid function, although most individuals tolerate high dietary intakes of iodine remarkably well [11]. Detrimental health effects including conditions such as iodine-induced hypothyroidism and hyperthyroidism and autoimmune thyroid disease such as Hashimoto thyroiditis or a history of partial thyroidectomy [2] are conditions resulting in excessive iodine.…”

The Hypothyroid Brain

“…Iodine deficiency in the diet can cause the thyroid gland to malfunction, and is a major cause of brain damage in the world [21] . Supplementation of iodine should be done through food.…”

Iodine content in salt sold in sea coastal province, Thailand: quality reflection

“…The important main source of iodine for human beings is the marine salt. The problem of iodine deficiency is common among the land lock countries [4][5][6] .…”