Prostate cancer rarely involves a single treatment. It may involve several therapies as well as many health care professionals from different specialties to decide the best treatment options, timing, and dosage. Also, the complications and side effects of prostate cancer may require attention from different experts.
Selenium is an essential trace mineral involved in a number of biological processes, including kinase regulation, gene expression, and immune function.
Animal and epidemiological studies have suggested there may be an inverse relationship between selenium supplementation and cancer risk.
The results of epidemiologic studies suggest some complexity in the association between blood levels of selenium and the risk of developing prostate cancer.
The Selenium and Vitamin E Cancer Prevention Trial (SELECT), a large multicenter clinical trial, was initiated to examine the effects of selenium and/or vitamin E on the development of prostate cancer.
Initial results of SELECT, published in 2009, showed no statistically significant difference in the rate of prostate cancer in men who were randomly assigned to receive the selenium supplements.
In 2011, updated results from SELECT showed no significant effects of selenium supplementation on risk, but men who took vitamin E alone had a 17% increase in prostate cancer risk compared with men who took placebo.
In 2014, an analysis of SELECT results showed that men who had high selenium status at baseline and who were randomly assigned to receive selenium supplementation had an increased risk of high-grade prostate cancer.
General Information and History
Selenium is an essential trace mineral involved in a number of biological processes, including enzyme regulation, gene expression, and immune function. Selenium was discovered in 1818 and named after the Greek goddess of the moon, Selene. A number of selenoproteins have been identified in humans, including selenoprotein P (SEPP), which is the main selenium carrier in the body and is important for selenium homeostasis.
Food sources of selenium include meat, vegetables, and nuts. The selenium content of the soil where food is raised determines the amount of selenium found in plants and animals. For adults, the recommended daily allowance for selenium is 55 µg /d. Most dietary selenium occurs as selenocysteine or selenomethionine. Selenium accumulates in the thyroid gland, liver, pancreas, pituitary gland, and renal medulla.
Selenium is a component of the enzyme glutathione peroxidase, an enzyme that functions as an antioxidant. However, at high concentrations, selenium may function as a pro-oxidant.