Sufficient selenium status is necessary for good thyroid health.
Zuo et al  have investigated selenium status and the effects of selenium supplementation in patients with autoimmune thyroid disease.
They analyzed the data from 17 journal articles based on studies of 1,911 subjects. Their meta-analysis results showed the following statistically significant associations:
- Serum free triiodothyronine (FT3) levels in patients were reduced after selenium supplementation compared to placebo treatment.
- Serum free thyroxine (FT4) levels and anti-thyroid peroxidase antibody (TPOAb) levels were reduced after selenium supplementation compared to placebo treatment.
- Anti-thyroid peroxidase antibody (TPOAb) levels were decreased after selenium supplementation compared to placebo treatment.
However, the thyroid stimulating hormone (TSH) levels
and the anti-thyroglobulin antibody (TGAb) levels were not significantly different between the selenium treatment group and the control group.
The researchers concluded that selenium-containing drugs were effective in treating patients with autoimmune thyroid disease and greatly reduced
the levels of free triiodothyronine, free thyroxine, and anti-thyroid peroxidase antibody in these patients.
Their findings suggest that selenium level has a considerable effect on patients with autoimmune thyroid disease and that selenium supplementation should be considered for these patients.
What is Autoimmune Thyroid Disease?
Autoimmune Thyroid Disease is described as an organ-specific
autoimmune condition caused by immune dysfunction in the body in which T lymphocytes are activated and B lymphocytes begin to produce large numbers of antibodies against the thyroid’s own antigens. The result is thyroid hormone metabolism disorders and autoimmune thyroid damage [Zuo 2021].
Autoimmune Thyroid Disease has a high incidence rate. It is more common in female patients. It can take the form of Graves’ disease, other forms of hyperthyroidism, Hashimoto’s disease, or other sub-clinical thyroid dysfunction [Zuo 2021].
Clinical markers of autoimmune thyroid disease are elevated antithyroglobulin antibody levels and elevated anti-thyroid peroxidase antibody levels [Zuo 2021].
Selenium’s Importance for Thyroid Function
The selenium content in the thyroid is higher than in any other organ except in the liver and the kidneys. Selenium is needed to regulate the levels of thyroid antibodies in patients with autoimmune thyroid disease. It is also needed for the biosynthesis of thyroid hormones in the body [Zuo 2021].
Studies have shown that selenium supplementation can improve the regulation of serum levels of TSH thyroid stimulating hormone, FT3 triiodothyronine, FT4 thyroxine, TGAb antithyroglobulin antibody, and TPOAb anti-thyroid peroxidase antibody [Zuo 2021].
Long Awaited Selenium and Thyroid Health Studies
At this writing (July 2021), we are still waiting for publication of the results from two important studies being conducted in Denmark:
- The Chronic Autoimmune Thyroiditis Quality of Life Selenium Trial (CATALYST Study) [Winther 2014]
- The Graves’ Disease Selenium Supplementation Trial (GRASS Study) [Ventura 2017]
We will summarize the results of these studies on seleniumfacts.com as soon as the published outcomes are available.
Bottom line: Selenium Status and Autoimmune Thyroid Disease
The meta-analysis showed that selenium supplementation and higher serum selenium status are associated with reductions in the serum concentrations of FT3 triiodothyronine, FT4 thyroxine, and TPOAb anti-thyroid peroxidase antibody [Zuo 2021].
Which form of selenium supplement to take? A 2014 comparative study has shown that selenium from a selenium-enriched yeast preparation is effective at reducing the levels of bio-markers for oxidative stress whereas similar dosages of pure selenomethionine are not [Richie 2014].
What level of serum selenium is best? Professor Margaret Rayman, in a 2020 review article, indicates that the serum/plasma selenium range between 90 mcg/L and 130 mcg/L is most beneficial for good health.
Rayman MP. Selenium intake, status, and health: a complex relationship. Hormones (Athens). 2020 Mar;19(1):9-14.
Richie JP Jr, Das A, Calcagnotto AM, Sinha R, Neidig W, Liao J, Lengerich EJ, Berg A, Hartman TJ, Ciccarella A, Baker A, Kaag MG, Goodin S, DiPaola RS, El-Bayoumy K. Comparative effects of two different forms of selenium on oxidative stress biomarkers in healthy men: a randomized clinical trial. Cancer Prev Res (Phila). 2014 Aug;7(8):796-804.
Ventura M, Melo M & Carrilho F. (2017). Selenium and thyroid disease: from pathophysiology to treatment. Int J Endocrinol; Article ID 1297658.
Winther KH, Watt T, Bjorner JB & Cramon P. (2014). The chronic autoimmune thyroiditis quality of life selenium trial (CATALYST): study protocol for a randomized controlled trial. Trials; 15: 115.
Zuo Y, Li Y, Gu X, Lei Z. The correlation between selenium levels and autoimmune thyroid disease: a systematic review and meta-analysis. Ann Palliat Med. 2021 Apr;10(4):4398-4408.
The information presented in this review article is not intended as medical advice and should not be used as such.
15 July 2021