What's Happening to Our Iodine?

[Guest guest]

I found this information (below in red) interesting as it infers that mild iodine deficiency may produce a response that is a hyper functioning autonomous nodule - that's exactly what we were discussing a few days ago when debating whether or not iodine makes some hyperthyroid. Here's the chicken / egg scenario once again.

http://jcem.endojournals.org/cgi/content/full/83/10/3398

The Journal of Clinical Endocrinology & Metabolism Vol. 83, No. 10 3398-3400Copyright © 1998 by The Endocrine Society

Special Articles

What’s Happening to Our Iodine?

T. Dunn

Department of Medicine, University of Virginia Health Sciences Center Charlottesville, Virginia 22908

Address all correspondence and requests for reprints to: T. Dunn, Department of Medicine, University of Virginia Health Sciences Center, Box 511, Charlottesville, Virginia 22908.

The iodine deficiency disorders include goiter, hypothyroidism, mental retardation, reproductive impairment, and decreased child survival, as extensively reviewed elsewhere (5–7). All stem from the insufficient thyroid hormone production that results from inadequate iodine supply. Endemic goiter is the first and most visible sign of iodine deficiency. The thyroid enlarges as an adaptation to the threat of inadequate hormone, a reaction mediated by TSH stimulation and perhaps other growth factors. In mild iodine deficiency, this response may be adequate to preserve euthyroidism, but at the cost of an enlarged thyroid and the attendant risks of neck compression and eventual hyperfunctioning autonomous nodules with hyperthyroidism. An insufficient adaptation in adults produces hypothyroidism with its usual clinical stigmata. The damage is greater when iodine deficiency provokes hypothyroidism during fetal or early life, because thyroid hormone is necessary for proper development of the central nervous system, particularly its myelination. Individuals who were hypothyroid at this critical period frequently have permanent mental retardation, which cannot be corrected by later administration of thyroid hormone or iodine. Child survival is also threatened by iodine deficiency, and several studies show that neonatal mortality decreases, sometimes by 50% or more, when the deficiency is corrected (8)