Selenium

Although needed in small amounts, the trace mineral selenium is vital for human health. It is needed for a healthy immune system and helps prevent diseases of the heart, blood vessels, and thyroid. Selenium may help prevent osteoarthritis, infertility, and certain forms of cancer. It is mainly attained through our diet; however, the amount of selenium in our food depends on how much of this mineral was in the soil the food was grown in. Selenium can also be destroyed during food processing. Unprocessed whole foods such as fish, wheat, and poultry are good sources.
A deficiency of this mineral is rare but can cause muscle pain, weakness, and loss of pigment in the hair and skin. If you eat a well-balanced diet, you should not have to worry about a selenium deficiency. Supplements may be needed by those who smoke, take birth control pills, or have a disease that prevents the body from absorbing selenium. Consult your healthcare provider if you are going to take more than the RDA; too much selenium may increase the risks of diabetes and high cholesterol.
-Natural Choices Magazine, August 2014