What Is Selenium and How Is It Used?

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What is Selenium used for? Selenium, a trace mineral, is used in our bodies as an antioxidant. Selenium is found in fruits, vegetables, nuts, wheat, fish, seafood, and meat. Selenium is common in vitamin and mineral supplements.

What Is Selenium Used For?

Selenium has many beneficial uses in keeping our bodies healthy and disease free. In addition it regulates our metabolism and thyroid.

Antioxidant Properties

Selenium boosts your immune system with its antioxidant properties. Antioxidants prevent free radicals from damaging your cell's DNA. We are exposed to free radicals everyday from the sun, air, additives, foods and more. Free radicals have been associated with an increase in cancer. Taking selenium may reduce your risks of the following cancers:

  • Bladder
  • Prostate
  • Colon
  • Lung
  • Pancreatic
  • Ovarian
  • Rectal
  • Skin

Heart Disease

Taking a selenium supplement may inhibit diseases such as cancer and heart disease. The antioxidants in selenium may reduce heart disease by lowering blood cholesterol.

Thyroid Function

Selenium, found in every cell of your body, regulates normal thyroid function. Without selenium your thyroid may slow down significantly.


Selenium is highly concentrated in our livers and kidneys and helps with their function in metabolism. Selenium is effective in metabolizing and moving excess mercury out of the body.


Many dandruff shampoos contain selenium. Selenium sulfide is an effective dandruff-fighting ingredient.

Selenium Deficiency

What is selenium used for is very apparent when populations of people are deficient in this essential mineral. Selenium deficiency is not common in the United States, but is seen in other countries, such as China, where the soil is low in selenium. People suffering from severe gastrointestinal disease such as Crohns, may deplete the selenium in their body through excessive diarrhea. Diseases and conditions associated with selenium deficiency are:

  • Heart disease
  • Hypothyroidism
  • Weakened immune system
  • Keshan Disease-an enlarged heart
  • Kashin Beck disease-form of osteoarthropathy
  • Mental retardation

Recommended Daily Value

Cancer studies have recommended adults get 200 mcgs a day of selenium. The Recommended Daily Allowance set by the United States Food and Drug Administration for selenium are:

  • Ages one to three: 20 mcg.
  • Ages four to eight: 30 mcg.
  • Ages nine to 13: 40 mcg.
  • Ages 14 and up: 55 to 70 mcg.
  • Pregnant and lactating: 60 to 70 mcg.

Foods That Contain Selenium

Plants and meat from animals that graze on grass are the major source of selenium throughout the world. Plant derived selenium is dependant on how much selenium is in the soil. Fish and seafood are high in selenium as well.

A few of the foods that contain selenium:

  • Mushrooms 193 mcg.
  • Asparagus 55 mcg.
  • Spinach 41 mcg.
  • Clams 410 mcg.
  • Lamb 262 mcg.
  • Brazil nuts 585 mcg.
  • Fish 170 mcg.
  • Tuna 139 mcg.
  • Wheat bran 72 mcg.
  • Spaghetti 42 mcg.
  • Egg white 83 mcg.

Study Supports Taking Selenium Supplement

A study done by Cornell University in conjunction with the University of Arizona indicates that both men and women who took a selenium supplement for 10 years developed cancer 41 percent less often than those who didn't.

In 2002 a study was done to see if selenium was effective in preventing prostate cancer. Selenium was shown to reduce the risk of prostate cancer in men who were taking selenium along with a vitamin E supplement.


As with any supplement, talk with your doctor before adding selenium above the recommended dosage to your diet. What is selenium used for in your situation may best be answered by your doctor.

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What Is Selenium and How Is It Used?