Two systematic review s have evaluated controlled trials among patients with autoimmune thyroiditis and report that selenium supplementation decreases circulating thyroid autoantibodies .
The immunomodulatory effects of selenium might involve reducing proinflammatory cytokine release .
In Graves ’ disease , some , but not all , trials indicate that adjuvant selenium supplementation enhances the restoration of biochemical euthyroidism , and might benefit patients with mild Graves ’ orbitopathy .
The available evidence from trials does not support routine selenium supplementation in the st and ard treatment of patients with autoimmune thyroiditis or Graves ’ disease .
However , correction of moderate to severe selenium deficiency may offer benefits in preventing , as well as treating , these disorders .
Purpose of review This review provides an appraisal of recent evidence for or against selenium supplementation in patients with autoimmune thyroid diseases , and discusses possible effect mechanisms .
Recent findings Epidemiological data suggest an increased prevalence of autoimmune thyroid diseases under conditions of low dietary selenium intake .
However , clinical ly relevant effects of selenium supplementation , including improvement in quality of life , are more elusive .
Selenium and the thyroid: A close-knit connection
Introduction : In areas with severe selenium deficiency higher incidence of thyroiditis has been reported due to a decreased activity of selenium-dependent glutathione peroxidase enzyme within thyroid cells . Aims and Objective : To study the effect of selenium supplementation in patients with autoimmune thyroid disease . Material s and Methods : This is a blinded placebo-controlled prospect i ve study done in 60 patients with autoimmune thyroid disease ( as defined by an anti-thyroid peroxidase antibody ( TPOAb ) level more than 150 IU/ml ) irrespective of the baseline thyroid status . Patients with overt hyperthyroidism who are on antithyroid drugs , patients on any other medication , which may alter the immunity status of the patients , and pregnant patients were excluded from the study . Patients were r and omized into two age and TPOAb-matched groups ; 30 patients  received 200 μg of sodium selenite/day , orally , for 3 months , and 30 patients  received placebo . All hypothyroid patients were given l-thyroxine replacement . Results : Of 30 patients in the selenium treated group , 6 patients were overtly hypothyroid , 15 were sub clinical hypothyroid , 6 were euthyroid , and 3 were sub clinical hyperthyroid . The mean TPOAb concentration decreased significantly by 49.5 % ( P < 0.013 ) in the selenium treated group versus 10.1 % ( P < 0.95 ) in the placebo-treated group . Conclusion : Selenium substitution has a significant impact on inflammatory activity in thyroid-specific autoimmune disease . It would be of interest to determine whether early treatment with selenium in patients with newly developed autoimmune thyroiditis may delay or even prevent the natural course of these diseases
Two systematic review s have evaluated controlled trials among patients with autoimmune thyroiditis and report that selenium supplementation decreases circulating thyroid autoantibodies .
The immunomodulatory effects of selenium might involve reducing proinflammatory cytokine release .
In Graves ’ disease , some , but not all , trials indicate that adjuvant selenium supplementation enhances the restoration of biochemical euthyroidism , and might benefit patients with mild Graves ’ orbitopathy .
The available evidence from trials does not support routine selenium supplementation in the st and ard treatment of patients with autoimmune thyroiditis or Graves ’ disease .
However , correction of moderate to severe selenium deficiency may offer benefits in preventing , as well as treating , these disorders .
Purpose of review This review provides an appraisal of recent evidence for or against selenium supplementation in patients with autoimmune thyroid diseases , and discusses possible effect mechanisms .
Recent findings Epidemiological data suggest an increased prevalence of autoimmune thyroid diseases under conditions of low dietary selenium intake .
However , clinical ly relevant effects of selenium supplementation , including improvement in quality of life , are more elusive .