Selenium is a trace mineral found in plants as well as some meat and seafood. The amount of selenium in foods is affected by how much selenium was in the soil they were grown in and how much the food has been processed. Good sources of selenium are brazil nuts, cashews, peanuts, eggs, alfalfa, mackerel, tuna, garlic, oysters, wholegrain cereals and yeast.

While people only need a very small amount, selenium plays a key role in the metabolism. Selenium functions as an antioxidant and in redox reactions and thyroid metabolism. It exerts it effects as a constituent of several selenoproteins an example being glutathione peroxidases.

Selenium deficiencies are uncommon. But some health conditions -- such as HIV, Crohn's disease are associated with low selenium levels. People who are fed intravenously are also at risk for low selenium. Selenium mineral deficiency in conjunction with iodine-deficiency has also been reported to increase the risk of cretinism.

Selenium supplements can be taken as selenium tablets/capsules, selenium liquid or as part of a multivitamin and mineral formula.

Where to buy selenium? Mr Vitamins sells a variety of selenium supplements, Australian made.