Supplement Spotlight: Selenium
Selenium was discovered in 1817 and named for Selene, the Greek goddess of the moon. Its role in health was only later recognized.
In the body, selenium is incorporated into selenoproteins that accomplish a number of functions. It has antioxidant and anti-inflammatory properties.
While occurring in trace amounts in a number of foods, including grains, meat, fish, seafood, dairy products and nuts, the amount available in food depends on soil conditions.
In areas with selenium-poor soil, supplementation can be beneficial for supporting optimal levels.
Are You Taking the Right Form?
It is available in different forms such as sodium selenite, sodium selenate, selenocysteine, L-selenomethionine, selenomethionine and Se-methyl L-selenocysteine. Each has a unique role in the human body.
Se-methyl L-selenocysteine is found in garlic and broccoli. It is essential to the formation of glutathione peroxidase, the body’s primary antioxidant.
Sodium selenite, L-selenomethionine, and selenium-methyl L-selenocysteine are superior for cancer protection.
Has Anti-Cancer Properties
Selenium may be best known for its cancer-preventive effect. A study conducted in Finland, uncovered an 80% lower risk of lung cancer among men whose toenail selenium concentrations (considered to be a good measure of long term levels) were among the highest.1
In another study, higher blood levels of selenium were associated with a lower risk of esophageal cancer in patients with Barrett’s esophagus, a precancerous condition.2
In 2004, the Journal of the National Cancer Institute published a study showing that higher blood levels of selenium were associated with a lower risk of colorectal adenoma, a precursor to colorectal cancer.3
High blood levels of selenium, along with a greater intake of folate have been linked to a lower risk of colon cancer.4
In 2005, the International Journal of Cancer reported a lower risk of fatal liver cancer in individuals with higher toenail selenium levels.5
Increased toenail selenium has also been associated with a lower risk of bladder cancer in women and moderate smokers.6
And in 2011, a study conducted in Spain found a 95% lower risk of pancreatic cancer among those with high toenail selenium levels.7
May Prolong Your Life
Having higher selenium levels may be associated with a longer life. A study in the Journal of Nutrition found a reduced risk of dying from any cause associated with increasing selenium levels.8
And in 2010, findings from the Third National Health and Nutrition Examination Survey revealed an association between reduced selenium levels and an increased risk of death.9
How Much Selenium Do You Need?
The National Institutes of Health recommends 55 micrograms per day for males and females aged 14 and older.
While higher doses of selenium have been suggested for cancer prevention or other purposes, the American Cancer Society recommends an upper limit of 400 micrograms per day.10
- Cancer Causes Control. 2002 Dec;13(10):923-8.
- J Natl Cancer Inst. 2003 May 21;95(10):750-7.
- J Natl Cancer Inst. 2004 Nov 17;96(22):1669-75.
- Nutr Cancer. 2009;61(2):165-78.
- Int J Cancer. 2005 Jul 1;115(4):618-24.
- Cancer Prev Res (Phila). 2009 Jan;2(1):70-3.
- Gut. 2012 Nov;61(11):1583-8.
- J Nutr. 2006 Jan;136(1):172-6.
- Atherosclerosis. 2010 Oct;212(2):689-94.
- Vitamin and mineral requirements in human nutrition. World Health Organization. 2004. Accessed June 28, 2014.