Editing Selenium (section)

===General health effects===
{{Main article|Selenium in biology}}
The effects of selenium intake on cancer have been studied in several [[clinical trial]]s and [[Epidemiology|epidemiologic]] studies in humans. Selenium may have a [[Chemopreventive|chemo-preventive]] role in [[cancer]] risk as an [[Antioxidant|anti-oxidant]], and it might trigger the immune response. At low levels, it is used in the body to create anti-oxidant [[selenoprotein]]s, at higher doses than normal it causes cell death.<ref name=":0" />

Selenium (in close interrelation with [[iodine]]) plays a role in thyroid health. Selenium is a cofactor for the three thyroid hormone [[deiodinase]]s, helping activate and then deactivate various thyroid hormones and their metabolites. Isolated selenium deficiency is now being investigated for its role in the induction of autoimmune reactions in the thyroid gland in [[Hashimoto's thyroiditis|Hashimoto's disease]].<ref>{{Cite journal |last1=Rostami |first1=Rahim |last2=Nourooz-Zadeh |first2=Sarmad |last3=Mohammadi |first3=Afshin |last4=Khalkhali |first4=Hamid Reza |last5=Ferns |first5=Gordon |last6=Nourooz-Zadeh |first6=Jaffar |date=2020-10-31 |title=Serum Selenium Status and Its Interrelationship with Serum Biomarkers of Thyroid Function and Antioxidant Defense in Hashimoto's Thyroiditis |journal=Antioxidants |volume=9 |issue=11 |pages=E1070 |doi=10.3390/antiox9111070 |issn=2076-3921 |pmc=7692168 |pmid=33142736|doi-access=free }}</ref> In a case of combined iodine and selenium deficiency was shown to play a thyroid-protecting role.<ref>{{Cite journal |last1=Vanderpas |first1=J. B. |last2=Contempré |first2=B. |last3=Duale |first3=N. L. |last4=Deckx |first4=H. |last5=Bebe |first5=N. |last6=Longombé |first6=A. O. |last7=Thilly |first7=C. H. |last8=Diplock |first8=A. T. |last9=Dumont |first9=J. E. |date=February 1993 |title=Selenium deficiency mitigates hypothyroxinemia in iodine-deficient subjects |journal=The American Journal of Clinical Nutrition |volume=57 |issue=2 Suppl |pages=271S–275S |doi=10.1093/ajcn/57.2.271S |issn=0002-9165 |pmid=8427203|doi-access=free }}</ref>