Commonly Ingested as:
Selenomethionine
Structure of Selenomethionine
Intro and Background
Selenium is an element (symbol: Se, atomic number: 34) commonly found in soil and is a component of the amino acid selenomethionine. (1) This naturally occurring amino acid is essential for proper nutrition and is most often ingested in meats, seafood and plant products. (2) (3) The amount of selenium found in plants and animals (including humans) depends on the selenium concentration of the soil where their food was grown. Investigators started to look at selenium as an anticancer agent when they discovered that the average selenium intake was lower among nations that showed an increased risk for cancer. (4)
Please read our notice on CAM and chemoprevention methods.
Scientific Research
In many studies, selenium is paired with Vitamin E to investigate their combined cancer fighting abilities. For the most part, research is focused on the ability of selenium to prevent cancer rather than treat existing cases. The exact mechanisms by which selenium influences cell behavior is unknown. In vitro selenium has been shown to alter the expression of many genes in cancer cells(5) and prevents harmful molecules from binding to and changing DNA. (6) The US Food and Drug administration suggests daily intake of about 70 µg (with a maximum of 400µg/day) for adults as part of a normal, healthy diet. (7) (2)
There is significant evidence that selenium is effective in the reduction of prostate cancer risk. (8) (9) Treatment of prostate cancer cells with selenium in vitro inhibited tumor cell growth and induced apoptosis. (1) (10) Studies have also shown that people are have a reduced risk for several cancer types when selenium is a consistent part of their diet. (7) (11) (12) Many of these studies suggest that a baseline, or minimum, level of selenium intake per day provides some protection from cancer development. (8) (7) (11) One study in particular is The Selenium and VItamin E Cancer Prevention Trial, also known as the SELECT Trial. The SELECT Trial was a large, long-term study being conducted on over 35,000 men with an objective to determine whether selenium, vitamin E, or both can prevent prostate cancer.
SELECT Trial Update:The SELECT trial has been canceled. Participants were told to stop taking the study pills, but they will be followed for 3 more years. SELECT committee members concluded there was no evidence showing vitamin E and selenium would reduce the risk of prostate cancer. (13)
Learn more about apoptosis
For information about ongoing clinical trials involving selenium, please visit our section on Finding Clinical Trials.
US Food and Drug Administration Approval
At this time there is not conclusive evidence that selenium can effectively prevent cancer. For this reason, selenium has not been approved for cancer prevention by the FDA.
Print
Email Page
