Selenium, as Methylselenocysteine, is an essential trace mineral that works as an antioxidant[1] – especially when combined with Vitamin E – by scavenging damaging particles in the body known as free radicals.

It is needed for proper immune system function and the production of substances that affect blood pressure and inflammation.

Low blood Selenium levels have been associated with abnormal liver structure and function, and can even lead to premature aging. Low levels of Selenium may worsen atherosclerosis (plaque buildup in arteries which can lead to a heart attack or stroke). Research supports this, showing an association between heart disease and depleted levels of Selenium.[2]

Observational studies indicate death from cancer is lower among people with higher blood levels or intake of Selenium.[3][4][5][6][7][8][9] Combined with other minerals, Selenium helps stimulate the activity and build up white blood cells, which helps strengthen the immune system to fight infection and illness.

As an antioxidant, Selenium can help neutralize the damaging effects of free radicals. For example, Selenium is important to the production of the enzyme glutathione peroxidase. Also, certain breakdown products of Selenium are believed to prevent tumor growth by enhancing immune cell activity and suppressing development of blood vessels to the tumor. [10]

Ingredient Research
1. Gladyshev VN. Selenoproteins and selenoproteomes. In: Hatfield DL, Berry MJ, Gladyshev VN, eds. Selenium: Its
    molecular biology and role in human health. 2nd ed. New York: Springer; 2006:99-114.
2. McKenzie RC, Rafferty TS, Beckett GJ. Selenium: an essential element for immune function. Immunol Today
3. Russo MW, Murray SC, Wurzelmann JI, Woosley JT, Sandler RS. Plasma selenium levels and the risk of colorectal
    adenomas. Nutr Cancer 1997;28:125-9.
4. Patterson BH and Levander OA. Naturally occurring selenium compounds in cancer chemoprevention trials: A
    workshop summary. Cancer Epidemiol Biomarkers Prev 1997;6:63-9.
5. Knekt P, Marniemi J, Teppo L, Heliovaara M, Aromaa A. Is low selenium status a risk factor for lung cancer? Am J
    Epidemiol 1998;148:975-82.
6. Fleet JC. Dietary selenium repletion may reduce cancer incidence in people at high risk who live in areas with low
    soil selenium. Nutr Rev 1997;55:277-9.
7. Shamberger RJ. The genotoxicity of selenium. Mutat Res 1985;154:29-48.
8. Young KL and Lee PN. Intervention studies on cancer. Eur J Cancer Prev 1999;8:91-103.
9. Burguera JL, Burguera M, Gallignani M, Alarcon OM, Burgueera JA. Blood serum selenium in the province of Merida,
    Venezuela, related to sex, cancer incidence and soil selenium content. J Trace Elem Electrolytes Health
    Dis 1990;4:73-7.
10.Combs GF, Clark LC, Turnbull BW. An analysis of cancer prevention by selenium. BioFactors 14 2001; 153-9.

Additional Resources