Selenium is a trace mineral that stimulates the immune system by playing a role in the production of an important antioxidant in the body called glutathione. It also works with vitamins C and E to support the body’s natural defense system, and prevents damaging free radicals from accumulating in the body. To that end, selenium is primarily used for antioxidant support and immune enhancement. In addition, selenium plays a role in the production of thyroid hormone, which supports a normal metabolism and helps the body produce energy.

The Wellness Advisor asked Rachel Agnew, RD, about how Selenium works.

Wellness Advisor: What is selenium and where is it used in the body?

Rachel Agnew: Selenium is an essential trace element and a powerful antioxidant. Selenium is transported by blood circulation to various tissues in the body.

WA: Why is selenium good for me?

Agnew: Selenium is best known for its role in the glutathione peroxidase enzyme system, a major antioxidant defense system in the body. These selenium-dependent enzymes reduce toxicity of metals and help prevent oxidative damage. Selenium also plays a major role in the synthesis and metabolism of thyroid hormones.

WA: What are the health benefits of selenium?

Agnew: Adequate selenium concentrations support healthy immune function and decrease oxidative stress. Several studies suggest that selenium supplementation appears to enhance immunity even in those without a selenium deficiency.

WA: Where does selenium occur naturally?

Agnew: The level of selenium in food is directly related to the level of selenium in the soil. In the United States, meats and breads are the most common dietary sources. Other good food sources include wheat germ, Brazil nuts, garlic, brown rice and oats.

WA: If I take selenium as a supplement, when and how much should I take?

Agnew: The Food and Nutrition Board recommends an intake of 55 micrograms daily for adults. Typical dosage ranges from 50 to 200 micrograms daily.