Selenium for the Thyroid
One of my clients told me her doctor was impressed with her remarkable changes in T3 simply by taking 200mcg of selenium a day. In fact, selenium deﬁciency decreases the synthesis of thyroid hormones. This is because it decreases the function of selenoproteins, in particular iodothyronine deiodinases (DIOs), which are responsible for the conversion of T4 to T3 (Ventura, Melo, & Carrilho, 2017). This decreased production of thyroid hormones leads to the stimulation of the HPA axis to produce TSH, due to lack of negative feedback. Hydrogen peroxide is produced as a byproduct of TSH stimulating DIO’s to convert T4 to T3, and this excessive H2O2 can accumulate and destroy the thyroid tissue.
I want to mention that eating Brazil nuts is also a simple way to supplement with selenium using whole foods. In fact, Brazil nuts are the richest known food source of selenium, with average concentrations ranging from 8 and 83ug selenium per gram (Thomson, Chisholm, McLachlan, & Campbell, 2008). The issue with this recommendation is that the amount of selenium greatly varies among Brazil nuts due to the variations in the quality of the soil.
The literature suggests that selenium supplementation of patients with autoimmune thyroiditis is associated with a reduction in antiTPO antibody levels, improved thyroid ultrasound features, and improved quality of life. This is because selenoproteins have a high level of antioxidant defense in the thyroid, can remove oxygen free radicals that are generated during the thyroid hormone production. “Being incorporated into iodothyronine deiodinases, selenium plays also an essential role in the metabolism of thyroid hormones” (Ventura et al., 2017). A study by Duntas et al conducted a study of patients with AID that were treated with thyroid medication and selenium. The results of the study demonstrated that group supplemented with selenomethionine had a 46% reduction in TPOAb at 3 months, 55.5% at 6 months. This remarkable compared to the control only taking levythyroxine, at 21% and 27% reduction only at 3 and 6 months. According to Ventura et al, the dose required to make significant changes in thyroid antibodies is greater than 100ug/day to maximize glutathione peroxidase activity. Therefore, other supplements to consider are N-acetyl cysteine to help ramp up glutathione levels as well as in some cases, liposomal glutathione. I like the S-Acetyl Glutathione Synergy by Designs for Health since it contains S-acetyl Glutathione, NAC and P5P (active B6). NAC provides the precursors to the production of glutathione, which can be an efficient way to support normal glutathione production in some cells. B6 is an essential cofactor in the enzymatic production of glutathione.
Considering that the organic form has better absorption, it seems to be the preferable formulation for supplementation. Careful monitoring should be done to ensure that the levels of selenium do not reach toxic levels, exceeding 400ug per day. “This rare situation was mainly reported by epidemiological studies in populations living in areas with high selenium concentration in the soil and can result from acute poisoning or prolonged exposure to high levels of selenium”(Ventura et al., 2017). Symptoms include nausea, vomiting, neuropathy, abdominal pain, diarrhea, and interestingly, the smell of garlic in sweat and breath. However, I believe this is a rare occurrence and minimal risk.
Designs for Health (n.d.). Glutathione Power and S-Acetyl Glutathione Synergy. [Handout]. Retrieved (2019) January 16 from https://catalog.designsforhealth.com/assets/itemresources/GlutathionePower_S-AcetylGlutathioneSynergy_Techsheet_REV7.16.pdf (Links to an external site.)
Thomson, C. D., Chisholm, A., McLachlan, S. K., & Campbell, J. M. (2008). Brazil nuts: an effective way to improve selenium status. Am J Clin Nutr, 87(2), 379-384. doi:10.1093/ajcn/87.2.379
Ventura, M., Melo, M., & Carrilho, F. (2017). Selenium and Thyroid Disease: From Pathophysiology to Treatment. Int J Endocrinol, 2017, 1297658. doi:10.1155/2017/1297658