Nutrition 101: Selenium

Selenium is a trace mineral that functions as an antioxidant in the body. It also helps the thyroid and immune system to function properly and may help protect again some cancers.

Recomme​​nded Intake

The Dietary Reference Intakes (DRI) for selenium are shown below:

What Does ​Selenium Do?

Selenium helps prevent oxidative stress by working as an antioxidant to fight damaging particles in the body called free radicals. To accomplish this, selenium works together with a group of nutrients including Vitamin E, Vitamin C, glutathione, and niacin. Free radicals can damage cell membranes and DNA, and may contribute to aging and a number of conditions, including cancer.

Selenium plays an important role in thyroid function and immune system function. Selenium is an essential mineral for maintaining proper function of the thyroid gland. Selenium is not only essential for the thyroid to produce the most active form of its hormone (called T3), but also helps regulate the amount of hormone produced.

Selenium may help protect against the development of some types of cancers, but this is still being studied. Selenium has been shown to induce DNA synthesis and repair damaged cells, thus inhibiting the proliferation of cancer cells. It also helps to induce the body’s process of eliminating worn out or abnormal cells. Additionally, selenium is a component of many proteins, including glutathione peroxidase, which is particularly important for cancer protection.

Top Selenium-Rich Foods

Selenium is present in soil; therefore, the amount of selenium in foods varies greatly depending on where the animal was raised or where the plant was grown. Brazil nuts are the most highly concentrated source of selenium. Meat, chicken, seafood, fish, eggs, grains, garlic, and mushrooms are also good sources of selenium.

Nutrition Facts Label and t​he % Daily Value

In the United States: The % daily value gives you an idea of how much selenium is in the food you eat. The daily value for selenium is 70 mcg, which is slightly higher than the DRI for adults. The number you see on the Nutrition Facts label is a percentage calculated by dividing the amount of selenium in one serving of the food by the DV. Using an example from the above table, 3 ounces of cooked halibut containing 47 mcg of selenium would have 67% of the DV for selenium. The FDA does not require that the % daily value for selenium be listed on the Nutrition Facts label.

In Canada: The daily value for selenium is 50 mcg, which is slightly lower than the DRI for adults. Using the same example as above, 3 ounces of cooked halibut containing 47 mcg of selenium would have 94% of the DV for selenium. Listing the daily value for selenium on the Nutrition Facts label is optional.

Nutrient Interactions

Iron and copper: Iron and/or copper deficiency may increase the risk for selenium deficiency

Carolyn Berry, RD

Alumni: University of British Columbia – Carolyn Berry is a Vancouver-based Registered Dietitian, self-proclaimed foodie, marathon runner, and owner of Berry Nourished. Carolyn works in a variety of areas including clinical nutrition, outpatient counselling at Medisys Preventive Health Clinic, as a nutrition tour leader with Save-On-Foods, and in the media, including segments on CBC Television, CKNW and Spice Radio. Through informative and practical nutrition advice and her food-first approach to health, Carolyn fulfills her passion to empower others with knowledge about nutrition so that they can make the best decisions to improve their health. She strongly believes that food should be both healthful and delicious.