Focus On: Selenium

What it is, why you need it, and where to get it.
By Brooke Holmgren

What it is: The mineral selenium is a micronutrient that must be ingested via food or drink. Selenium helps regulate the thyroid and combines with proteins to make selenoproteins, a type of antioxidant that protects against cellular damage.


Selenium deficiency is rare in the United States; however, individuals with conditions such as Keshan Disease, Kashin-Beck Disease, and Myxedematous Endemic Cretinism are known to be chronically deficient in selenium. People with an iodine deficiency may benefit from selenium supplementation as it protects against damage that can occur to the thyroid.

Selenium is known to prevent and treat diseases of the cardiovascular system, macular degeneration, cataracts, chronic fatigue syndrome, hay fever, mood disorders, and even arsenic poisoning. It is most often used to treat Hashimoto’s thyroiditus as it decreases specific antibodies attributed to the thyroid disease.


Selenium supplements are only necessary for people with severe gastrointestinal problems or who have been diagnosed deficient by a healthcare professional.

Recommended Dosage

Age (years) Mcg/day (male & female) Pregnancy mcg/day Lactation mcg/day

1-3                               20                                n/a                                n/a

4-8                               30                                n/a                                n/a

9-13                             40                                n/a                                n/a

14-18                          55                                60                                  70

19+                              55                                60                                  70

Natural Sources

Crab, fish, liver, lobster, mushrooms, tuna, poultry, and wheat are good sources of selenium. Brazil nuts contain the highest amount of selenium of all foods, yet this is dependant upon soil content.

Selenium Picks

Now Selenium, 180 capsules, $8, // New Chapter Selenium Food Complex, 90 tabs, $22, // Source Naturals Selenium, $13, 120 tablets, // Jarrow Selenium Synergy, $13, 60 capsules,