Selenium is an essential mineral for the proper functioning of your thyroid gland and also plays many other roles in the body. Selenium is incorporated into proteins to make selenoproteins. These are important antioxidant enzymes which are thought to play a role in protecting the body from free radicals and toxins. Hence, this nutrient may be valuable in the treatment of cancer [I].

Selenium is also important for vitamin C metabolism, improving blood flow, enhancing immune function, and slowing the aging process. Eating just one selenium-rich brazil nut a day could help to slow the aging process. Sounds much better than a facial peel or Botox® to me!

Selenium and the Thyroid

The butterfly-shaped gland in the front center of your throat area regulates an immense amount of functions in the body. One of the main functions of the thyroid gland is controlling the metabolism. When this becomes unregulated, your weight, mood, sleep, appetite and energy are all effected. Selenium activates the production of thyroid hormones, so without it, a whole host of problems arise.

Selenium Deficiency

When your body is low in this mineral, you may experience white spots on your fingernails, joint pain, fatigue, brain fog and hair thinning or loss. A long-term deficiency can lead to thyroid conditions such as Hashimoto’s and other disorders.

Recommended Daily Allowance (RDA)

Men and Women 55 mcg/day
Upper Level Dosage (UL) 400 mcg/day

Food Sources of Selenium

Animal sources: seafood, halibut, tuna, salmon, oysters, chicken, pork, beef, and turkey

3.5 ounces halibut—60.0 mcg
2 oysters—77 mcg
3 ounces mussels—76.2 mcg
½ chicken breast, bone and skin removed—23.7 mcg

Plant sources: nuts, garlic, and brewer’s yeast

1 ounce of brazil nuts—over 500 mcg
½ cup sunflower seeds—51 mcg
1 cup uncooked kamut—129 mcg
2 tablespoons brewers yeast—roughly 46 mcg
3 ounces orange—roughy 56.7 mcg
3 cloves garlic—1.3 mcg

The selenium content of plant food depends on the quality of soil in which the foods are grown. Regardless, brazil nuts seem to be the most highly concentrated source of selenium. In fact, scientists have shown that a daily brazil nuts is a better source of the mineral than taking a supplement [II]. One brazil nut a day in exchange for slowing the aging process, increasing immunity and improving thyroid health? That doesn’t seem like a bad deal!



[I] Clement, Ip. “Lessons from basic research in selenium and cancer prevention.” J. Nutr. November 1, 1998; vol. 128 no. 11 1845-1854. Web. May. 2016. <>.

[II] Thomson C, Chisholm A, McLachlan S, Campbell J. “Brazil nuts: an effective way to improve selenium status.” American Journal of Clinical Nutrition, February 2008; vol. 87 no. 2 379-384. Web. May. 2016. <>.