Abstract and key points
- Selenium is nutritionally essential for human health.
- Evidence from two systematic reviews of randomised controlled trials does not support the use of selenium supplements for cancer prevention in populations with an adequate baseline selenium status.
- Selenium is toxic in high doses and might have adverse effects when taken at supranutritional doses for longer periods of time.
This summary is currently (April 2016) being updated, the version published here was last updated in OCtober 2013.
The trace element selenium is a nutrient essential to human health and occurs naturally in a variety of foods. Inorganic forms (e.g. sodium selenite or selenate) and organic forms (e.g., selenomethionine) are both used in large numbers of selenium-containing medications, nutritional supplements or dietary aids that are promoted for medical or health purposes. These may contain either selenium alone (mono-supplements) or selenium in combination with other trace minerals as well as vitamins. Supplemental selenium has been advocated as an aid to cancer prevention.
Two recent systematic reviews have evaluated the preventive efficacy of selenium mono-supplements for cancer. Both reviews concordantly found no preventive effect of selenium for non-melanoma skin cancer and prostate cancer; one reported no preventive effect of selenium against stomach, colorectal, oesophageal or lung cancer. The two reviews disagreed regarding the evaluation of selenium for liver-cancer prevention: while one review reported a preventive effect (based on five studies), the other reported no strong indication of a preventive effect (based on three studies).
Although a number of health problems have been linked to selenium deficiency, selenium is also toxic in large doses. The safety of long-term intake of nutritional doses is a controversial issue, which continues to be discussed. Long-term supplementation has caused symptoms of chronic overexposure and has also been linked to increased risks of developing type 2 diabetes mellitus in two randomised clinical trials.
CitationGabriele Dennert, CAM-Cancer Consortium. Selenium prevention [online document]. http://cam-cancer.org/The-Summaries/Dietary-approaches/Selenium-prevention. October 20, 2013.
Summary first published in November 2010, authored by Gabriele Dennert.
Original summary divided into “Selenium – prevention” and “Selenium – during cancer treatment”, fully revised and updated in October 2013 by Gabriele Dennert.
- Rayman MP, Infante HG, Sargent M. Food-chain selenium and human health: spotlight on speciation. Br J Nutr 2008; 100: 238-53.
- Dietay supplement fact sheet: Selenium. http://ods.od.nih.gov/factsheets/Selenium-HealthProfessional/ (accessed 01/10/2012).
- Selenium. In: FAO & WHO: Human vitamin and mineral requirements. Report of a joint FAO/WHO expert consultation, Bangkok, Thailand. 2002. http://www.fao.org/DOCREP/004/Y2809E/y2809e0l.htm#bm21.1 (accessed 01/10/2012).
- National Cancer Institute: Antioxidants and Cancer Prevention: Fact Sheet http://www.cancer.gov/cancertopics/factsheet/prevention/antioxidants (last access 29/06/2013).
- Arnaud J, Bertrais S, Roussel AM, Arnault N, Ruffieux D, Favier A, Berthelin S, Estaquio C, Galan P, Czernichow S, et al. Serum selenium determinants in French adults: the SU.VI.M.AX study. Br J Nutr 2006; 95(2): 313-20.
- Burri J, Haldimann M, Dudler V. Selenium status of the Swiss population: Assessment and change over a decade. J Trace Elem Med Biol 2008; 22(2): 112-9.
- Kvieala J, Zamrazil V, Jiranek V. Selenium Deficient Status of Inhabitants of south Moravia. In: Kumpulainen JT, Salonen JT (Ed.). Natural Antioxidants and Food Quality in Atherosclerosis and Cancer Prevention. Cambridge: The Royal Society of Chemistry; 1996. 177-87.
- Klapcinska B, Poprzecki S, Danch A, Sobczak A, Kempa K. Selenium levels in blood of upper silesian population: evidence of suboptimal selenium status in a significant percentage of the population. Biol Trace Elem Res 2005; 108(1-3): 1-16.
- Vinceti M, Rovesti S, Bergomi M, Vivoli G. The epidemiology of selenium and human cancer. Tumori 2000; 86(2):105-18.
- Rayman MP. The use of high-selenium yeast to raise selenium status: how does it measure up? Br J Nutr 2004; 92(4): 557-73.
- WHO 2004: Joint FAO/WHO Expert Consultation on Human Vitamin and Mineral Requirements (1998): Bangkok T. Vitamin and mineral requirements in human nutrition : report of a joint FAO/WHO expert consultation, Bangkok, Thailand, 21-30 September 1998. http://whqlibdoc.who.int/publications/2004/9241546123.pdf 2004.
- Reilly C. Selenium in food and health. 2nd Edition. New York: Springer 2006. here: pp. 46ff.
- Rayman, MP: Selenium and human health. Lancet 2012; 379: 1256–68.
- Fairweather-Tait SJ, Bao Y, Broadley MR, Collings R, Ford D, Hesketh JE, Hurst R: Selenium in Human Health and Disease. Antioxidants & Redox Signaling 2011; 14: 1337-1383
- Lee JH, Shin SH, Kang S, Lee YS, Bae S: A novel activation-induced suicidal degradation mechanism for Akt by selenium. Int J Mol Med. 2008; 21: 91–97.
- Li Z, Shi K, Guan L, Cao T, Jiang Q, Yang Y, Xu C: ROS leads to MnSOD upregulation through ERK2 translocation and p53 activation in selenite-induced apoptosis of NB4 cells. FEBS Lett. 2010; 584(11): 2291-7.
- OTC ingredients. search for “selenium” via: http://www.aesgp.eu/facts-figures/otc-ingredients/ (last access29/06/2013).
- Dennert G, Zwahlen M, Brinkmann M, Vinceti M, Zeegers MPA, Horneber MA. Selenium for preventing cancer. Cochrane Database Syst Rev 2011; 11(5): CD005195. doi: 10.1002/14651858.CD005195.pub2
- Lee, EH, Myung, SK, Jeon, YJ, Kim, Y, Chang, YJ, Ju, W, Seo, HG, Huh, BY: Effects of selenium supplements on cancer prevention: Meta-analysis of randomized controlled trials. Nutr Cancer 2011; 63: 1185-1195.
- Dreno B, Euvrard S, Frances C, Moyse D, Nandeuil A: Effect of selenium intake on the prevention of cutaneous epithelial lesions in organ transplant recipients. Eur J Dermatol 2007; 17: 140-145.
- Li H, Li HQ, Wand Y, Xu HX, Fan WT, Wang ML, Sun PH, Xie XY: An intervention study to prevent gastric cancer by micro-selenium and large dose of allitridum. Chin Med J 2004; 117: 1155-1160.
- Yu SY, Zhu YJ, Li WG, Huang QS, Huang CZ, Zhang QN, Hou C: A preliminary report on the intervention trials of primary liver cancer in high-risk populations with nutritional supplementation of selenium in China. Biol Trace Elem Res 1991; 29: 289-294.
- Reid ME, Duffield-Lillico AJ, Slate E, Natarajan N, Turnbull B, Jacobs E, Combs GF, Jr., Alberts DS, Clark LC, Marshall JR. The nutritional prevention of cancer: 400 mcg per day selenium treatment. Nutr Cancer 2008; 60(2): 155-63.
- Lippman SM, Klein EA, Goodman PJ, et al: Effect of Selenium and Vitamin E on Risk of Prostate Cancer and Other Cancers: The Selenium and Vitamin E Cancer Prevention Trial (SELECT). JAMA 2009; 301(1):39-51
- Sutter ME, Thomas JD, Brown J, Morgan B. Selenium toxicity: a case of selenosis caused by a nutritional supplement. Ann Intern Med 2008;148(12): 970-1.
- SCF (Scientific Committee on Food): Opinion of the Scientific Committee on Food on the Tolerable Upper Intake Level of Selenium. 2000. http://ec.europa.eu/food/fs/sc/scf/out80g_en.pdf (last access 29/06/2013).
- Stranges S, Marshall JR, Natarajan R, Donahue RP, Trevisan M, Combs GF, Cappuccio FP, Ceriello A, Reid ME: Effects of Long-Term Selenium Supplementation on the Incidence of Type 2 Diabetes: A Randomized Trial. Ann Intern Med 2007; 147:217-223.
- See KA, Lavercombe PS, Dillon J, Ginsberg R. Accidental death from acute selenium poisoning. Med J Aust 2006; 185(7): 388-9.
- Sandström B: Micronutrient interactions: effects on absorption and bioavailability. Br J Nutr 2001; 85: S181-S185.
The present documentation has been compiled by the CAM-CANCER Project with all due care and expert knowledge. However, the CAM-CANCER Project provides no assurance, guarantee or promise with regard to the correctness, accuracy, up-to-date status or completeness of the information it contains. This information is designed for health professionals. Readers are strongly advised to discuss the information with their physician. Accordingly, the CAM-CANCER Project shall not be liable for damage or loss caused because anyone relies on the information.