Key Concepts

  • RDA – 55 mcg/day
  • UL – 400 mcg/day
  • Food Sources: Brazil nuts, meat, seafood, eggs, whole grains, brown rice, mushrooms, produce (soil dependent)
  • 1 Brazil nut provides your daily intake needs for selenium

Recommended Dietary Allowance (RDA)

The RDA for selenium is 55 mcg/day.


Selenium is incorporated into proteins; twenty-five selenoproteins have been identified. Selenomethionine appears to be the best absorbed at 90% while others are absorbed between 40 and 50%.

Selenoproteins are components of antioxidant systems such as glutathione peroxidase and thioredoxin reductase. Glutathione peroxidases protect against reactive oxygen species while thioredoxin reductases recycle vitamin E, vitamin C, CoQ10, and alpha lipoid acid.

Selenium is important for proper thyroid function. Selenium is incorporated into iodothyronine deiodinase and allows thyroxine (T4) to be converted to triiodothyronine (T3). Without adequate selenium intake hypothyroidism can occur.


A selenium deficiency may exacerbate and iodine deficiency. A selenium deficiency can cause immune dysfunction. Keshan Disease, a cardiac abnormality in which cardiac muscle becomes fibrous, has been linked to selenium deficiency in regions of China.

Toxicity/Excess/Upper Intake Level (UL)

The UL for selenium is set at 400 mcg/day. Excessive intake of selenium can lead to loss and brittleness of the hair and nails.

Food Sources

  • Brazil nuts, 1 ounce (6–8 nuts) – 544 mcg – 777% DV
  • Sardines, canned in oil, drained solids with bone, 3 ounces – 45 mcg – 64% DV
  • Rice, brown, long-grain, cooked, 1 cup – 19 mcg – 27% DV
  • Egg, hard-boiled, 1 large – 15 mcg – 21% DV
  • Baked beans, canned, plain or vegetarian, 1 cup – 13 mcg – 19% DV
  • Spinach, frozen, boiled, 1 cup – 11 mcg – 16% DV
  • Lentils, boiled, 1 cup – 6 mcg – 9% DV

Selenium content of plant foods is dependent on the levels of selenium in the soil. Selenium is a mineral that appears to be heavily impacted by conventional farming practices such as monocropping. Selenium levels of soils has been reduced several fold over the past 60 years.



Facebook Comments