Selenium

Selenium is a mineral found in the soil. Selenium naturally appears in water and some foods. While people only need a very small amount, selenium plays a key role in the metabolism.

Selenium uses

Selenium has attracted attention because of its antioxidant properties. Antioxidants protect cells from damage. There is some evidence that selenium supplements may reduce the risk of prostate cancer. 

The NHS says "some research has shown that prostate cancer rates appear to be lower in people who eat foods containing certain nutrients including lycopene, found in tomatoes and other red fruit, and selenium, found in brazil nuts."  

However, results are unclear. For instance, one 2009 randomised study, published in the Journal of the American Medical Association, looked at the effect of selenium and Vitamin E on prostate and other cancers. Researchers concluded "selenium or vitamin E, alone or in combination at the doses and formulations used, did not prevent prostate cancer in this population of relatively healthy men."

Selenium does not seem to affect the risk of colorectal or lung cancer. But beware: selenium also seems to increase the risk of non-melanoma skin cancer.

Some health conditions - such as HIV, Crohn's disease and others - are associated with low selenium levels. People who are fed intravenously are also at risk of

Selenium does not seem to affect the risk of colorectal or lung cancer. Beware: selenium also seems to increase the risk of non-melanoma skin cancer.

Some health conditions - such as HIV, Crohn's disease and others - are associated with low selenium levels. People who are fed intravenously are also at risk of low selenium. Doctors sometimes suggest that people with these conditions use selenium supplements.

Selenium has also been studied for the treatment of dozens of conditions, ranging from asthma to arthritis to dandruff to infertility. However, the results have been inconclusive.

Selenium dose and instructions for use

The recommended daily amounts (RDA) include the total amount of selenium you should get from foods and from any supplements you take. Most people can get their RDA of selenium from food.

The UK recommended nutritional intake (RNI) for selenium is 75mcg for adult men and 60mcg for women. The new EU RDA is 55mcg.

The upper safe level for long-term use from supplements is 350 micrograms a day in adults. Anything above that is considered an overdose.

In studies supporting the use of selenium for prostate cancer prevention, men took 200 micrograms daily.

Selenium food sources

Good natural food sources of selenium include:

• Nuts like Brazil nuts and walnuts
• Many fresh- and salt-water fish like tuna, cod, red snapper and herring

Whole foods are the best sources of selenium because the mineral may be destroyed during processing.

Selenium supplement information

Selenium supplements may be sold as tablets, capsules or topical treatments. Like any supplement, keep selenium supplements in a cool, dry place, away from humidity and direct sunlight.