Should iodine be avoided in autoimmune thyroid conditions?
The controversy is around thyroperoxidase (TPO) which is an enzyme that is necessary for the production of both T3 and T4. There is some evidence that consuming iodine will increase the TPO antibodies, which are the main antibodies found in people with Hashimoto’s Thyroiditis, and are also found in Graves’ Disease. Some studies that show that increased iodine intake in certain countries correlates with an increased incidence of autoimmune thyroid disease, mainly Hashimoto’s Thyroiditis. Other studies found that those people were deficient in selenium. Numerous studies have shown an increase in thyroid antibodies in those with a selenium deficiency. Adequate selenium is important for the oxidation of iodide to iodine. If there isn’t sufficient selenium then this can cause oxidative damage and trigger an autoimmune response. Many people are not aware that Lugol’s solution (iodine) was commonly used to treat Grave’s disease before radioactive iodine treatment was used.
Answer: Iodine supplementation needs to be paired with selenium
Chen X et al. Effect of excessive iodine on immune function of lymphocytes and intervention with selenium. J Huazhong Univ Sci Technolog Med Sci. 2007;27(4):422–425.
Zagrodzki P, Ratajczak R. Selenium supplementation in autoimmune thyroiditis female patient– effects on thyroid and ovarian functions (case study). Biol Trace Elem Res. 2008;126:76–82.