The mechanism by which excess iodine causes hyperthyroidism involves the regulation of thyroid hormone synthesis. Normally, iodine is absorbed and utilized by the thyroid gland to produce thyroxine (T4) and triiodothyronine (T3). However, when iodine levels are excessively high, it can bypass the normal regulatory mechanisms, particularly in individuals with a predisposed thyroid condition. This can lead to thyrotoxicosis, a state where excess thyroid hormones circulate in the bloodstream, causing symptoms such as weight loss, rapid heart rate, and increased metabolism.
