Selenium Sources and Functions

Selenium Sources and Functions

All of the nutrient minerals work together to keep you healthy and feeling good. Here is a summary of the role of selenium, a trace mineral, in your good health.

What it does Functions in antioxidant activity;Activation of thyroid hormone
Daily needs [Infants: 15-20 µg] [Children: 20-55 µg] [Men: 55 µg] [Women: 55 µg] [Pregnant: 60 µg] [Lactating: 70µg]]
Not enough Severe deficiency may lead to heart disease
Too Much Skin problems including rash; hair loss; irritability; bad breath
Foods Organ meats, seafood, meat, grains, Brazil nuts, vegetables and fruits

*The lower value is for infants up to 6 mos., higher value is for infants up to a year old.
† The first value is for children 1-3 with the amount increasing until age 18.

Just a trace

Note that the adequate daily intake of selenium is given in micrograms (µg). A microgram is .0001 milligrams (mg), so it is a very small amount. Only a trace of this mineral is needed, but it is nevertheless very necessary to your good health.


Selenium functions in your body as an antioxidant mineral that helps protect you from the damaging effects of free radicals, by helping to block the formation of these unstable and highly reactive molecules. In addition, selenium forms part of the enzyme that activates the thyroid hormone.

Interesting Fact:  Selenium can substitute for sulfur in certain proteins if no sulfur is available.

Deficiency is rare

Most people get enough selenium, and when deficiency does occur, it is generally associated with digestive disorders such as Crohn’s Disease or with poor or restricted diets. Since selenium is found in the soil, the selenium content of fruits and vegetables varies based on the amount of selenium in the soil.

Fun Fact: Brazil nuts are one of the best sources of selenium. Just one ounce of these nuts can supply as much as 700% of the daily requirement for selenium, so you should eat them sparingly. Vegetarians can eat Brazil nuts as a non-meat source of this important mineral.

Can be Toxic

Too much selenium in your diet can be toxic. If you choose to take selenium supplements, be aware of the dose and consider carefully whether it is necessary, since most people in developed countries get more than the recommended daily amount of selenium in their diet. Selenium toxicity is unlikely to occur when the only source is food.

Interesting Fact: Selenium and Vitamin E are often taken together in supplemental form, since they work together to prevent formation of those bad actors called "free radicals."

Man holding heart

Preventing disease

Research has shown that selenium deficiency is linked with heart disease. However, there is no evidence that taking excessive amounts of selenium will help your heart. Instead, eating a diet that contains fresh, whole foods will provide the selenium your body needs to maintain good heart health.

There is also evidence that getting enough selenium in your diet will help prevent cancer. This is most likely due to its antioxidant activity. Selenium is also necessary for healthy immune function.

Upper Level

The upper intake level for adults for selenium has been established at 400 µg per day.

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