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 .
The effect of levothyroxine and selenomethionine on lymphocyte and monocyte cytokine release in women with Hashimoto's thyroiditis.
CONTEXT No previous study determined monocyte- and lymphocyte-suppressing effects of levothyroxine and selenomethionine and assessed whether their coadministration is superior to treatment with only one of these drugs . OBJECTIVE Our objective was to compare the effect of levothyroxine and selenomethionine on monocyte and lymphocyte cytokine release and systemic inflammation in patients with Hashimoto 's thyroiditis . DESIGN , SETTING , PARTICIPANTS , AND INTERVENTION We conducted a r and omized clinical trial involving a group of 170 ambulatory euthyroid women with recently diagnosed and previously untreated Hashimoto 's thyroiditis and 41 matched healthy subjects . Participants were r and omized in a double-blind fashion to receive a 6-month treatment with levothyroxine , selenomethionine , levothyroxine plus selenomethionine , or placebo .  One hundred sixty-five patients completed the study . MAIN OUTCOME MEASURES Monocyte and lymphocyte release of proinflammatory cytokines and plasma levels of C-reactive protein ( CRP ) were assessed . RESULTS Compared with the control subjects , monocytes and lymphocytes of Hashimoto 's thyroiditis patients released greater amounts of all cytokines studied . Levothyroxine  reduced monocyte release of TNF-α , IL-1β , IL-6 , and monocyte chemoattractant protein-1 , whereas selenomethionine inhibited lymphocyte release of IL-2 , interferon-γ , and TNF-α , which was accompanied by a reduction in plasma CRP levels . The decrease in cytokine release and in plasma CRP levels was strongest when both drugs were given together . CONCLUSIONS Despite affecting different types of inflammatory cells , levothyroxine and selenomethionine exhibit a similar systemic antiinflammatory effect in euthyroid females with Hashimoto 's thyroiditis . This action , which correlates with a reduction in thyroid peroxidase antibody titers , may be associated with clinical benefits in the prevention and management of Hashimoto 's thyroiditis , particularly in subjects receiving both agents
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 .