Nonessential Micronutrient



Our bodies use the trace mineral selenium to create “glutathione peroxidase.” This accounts for its powerful antioxidant properties, which support healthy immune functioning and may help explain why it’s able to help fight off a variety of diseases and even protect cells from deterioration and aging. In fact, low soil levels of selenium have actually been associated with higher cancer rates, and soil rich in selenium leads to a below-average rate for a number of cancers. Certainly, there are no coincidences here.

Other names for Selenium


Where to find Selenium

Selenium is ever present, although in varying amounts, in the soil, where we grow our fruits and vegetables. Other great sources include meats, seafood, whole grains, yeast, wheat germ, and most notably, Brazil nuts (which have very high concentrations).

Notes Unfortunately, some of the soil our food is grown in has long ago been stripped of its natural selenium. Plus, the selenium found in most foods is lost when processed, increasing the risks of deficiencies.

Selenium is available in two forms — the organic, which according to some experts may be better absorbed, and the inorganic form called selenate.

Popup: Foods highest in Selenium


Why athletes use Selenium

Because the risk for deficiencies are high and the symptoms of such deficiencies can include increased risks for cancer, heart disease, and a number of other illnesses, active people are starting to look more closely at this powerful antioxidant. Because exercise can increase levels of free radicals in the body, selenium, usually found in an antioxidant formula, may be beneficial for intensely training athletes to help them boost immune functioning.

Ways that Selenium can enhance Longevity:
  • Activate the powerful antioxidant glutathione to fight off potentially dangerous free radicals
  • Stimulate the production of white blood cells to enhance immune functioning
  • Impart “normal” thyroid functioning to support a healthy metabolism


Signs of Selenium deficiency

Deficiency of Selenium has been linked to:

  • Keshan disease
  • KashinBeck disease
  • Heart enlargement
  • Fatigue/Weakness
  • Increased risk for cancer
  • Cardiovascular risk
  • Impaired immune function
  • Sickle cell anemia
  • Macular degeneration
  • Birth defects
  • Arthritis
  • Cataracts
  • Autoimmune diseases
  • Asthma
  • Herpes
  • Infections
  • Sterility
Potential uses for Selenium

Research indicates that Selenium may also be useful in the treatment of:

  • Cancer
  • Cardiovascular disease
  • Depression
  • Arthritis
  • Aches and pains
  • Dermatitis
  • Addictions
  • Rheumatoid arthritis
  • Skin conditions, such as eczema or psoriasis
  • Cataracts
  • Asthma
  • Cirrhosis
  • Prostate enlargement


More about Selenium

Just a few decades back, there was a great debate regarding this trace mineral that was once found abundantly in soil. Some experts thought it was essential for animals but dangerous to humans. Now, thanks to science, that debate has been put to rest, and nutritional experts agree this is one miraculous, and very much essential, mineral.

Why it’s so important

Selenium is needed for our bodies to create something called “glutathione peroxidase,” which our bodies then use as an antioxidant. Thus, selenium is essential for healthy immune functioning and may, in fact, be able to help fight a variety of diseases and even protect cells from aging and natural degeneration — hence the reason selenium is sometimes suggested for “fighting cancer.” It’s that powerful.

Its potential to stimulate the immune system, especially when combined with Vitamin E, has been shown to be beneficial when fighting recurrent illnesses, infections, and inflammation. Research also suggests selenium helps build resistance to disease, decreases infection rate, and allows quicker recovery for burn victims.

Selenium supports immune functioning two additional ways — it appears to stimulate both white blood cell production and thymus functioning — both required to keep us healthy and vibrant.

Could it lower the risk of cancer?

Many studies have shown that where selenium is abundant in the soil or added to the diet, cancer rates decrease, particularly with breast, colon, rectum, prostate, lung, ovarian, bladder, pancreas, and skin cancers. Research has also shown it may decrease mortality rates in people who already have cancer as well as potentially preventing tumors in those who don’t.

One study, for example, showed that people given 200 mcg of selenium for 7 years had a 50% decrease in cancer rate, and the men had a 65% drop in prostate cancer. For this reason, there’s strong evidence to believe it may be anti-carcinogenic or, at the very least, instigate some additional research in this area.

Lower the risk for heart disease?

Heart disease is a concern for many Americans (for good reason — it’s the number one killer), and again, as with cancer findings, the rates for heart disease are highest in areas where selenium intake is low or where very little amounts are found in the soil. Because it fights free radicals, scientists theorize it may help decrease the number of clogged arteries and reduce inflammation in the heart. It’s also been shown to increase HDL cholesterol (the “good” fat) and decrease the bad LDL cholesterol as well as helping the blood flow more smoothly through our arteries by making it less “sticky.” One study showed a decrease in symptoms in almost 100% of the patients who supplemented with selenium and Vitamin E.

Additional benefits

Selenium, especially when combined with Vitamin E, has also been linked to anti-aging properties because it appears to inhibit physical and mental deterioration while supporting the metabolism by stimulating healthy thyroid functioning — keeping our bodies from feeling sluggish or out of sorts.

It may also be significantly beneficial for anyone suffering from inflammatory conditions, such as arthritis, because it fights the substances that cause the damage to tissues. Studies have shown selenium may reduce joint swelling, tenderness, and morning stiffness.

Selenium, because of its role in the production of glutathione peroxidase in the eyes’ lens, has been shown to have significant preventative effects on cataract formation.

Because glutathione peroxidase helps protect against the damaging effects of ultraviolet light, selenium may also be important for preventing and perhaps even treating sunburn and other forms of sun damage.

Deficiency issues

Much of selenium’s recent popularity for its positive effects may be because so many people are suffering from a deficiency. You see, the amount in the foods we eat depends largely on the amount in our soil. And since the amounts in much of the soil have been depleted, there is a greater chance for deficiencies. Combine that with the fact that selenium in food is lost when the food is processed and refined, and we could be unknowingly shortchanging ourselves of this valuable trace mineral.

This is significant because numerous studies have shown that a deficiency of selenium may lead to an increased risk of cancer, heart disease, and a variety of other unhealthy states. In fact, people with low levels of selenium are found to have a higher rate of asthma, disease, infections, sterility, exhaustion, and birth defects. Plus, lacking enough of this mineral may also cause sore and weak muscles.

Risks of deficiency are even greater for young adults, vegetarians, the elderly, smokers, and people who are exposed to toxic chemicals.

Not just for those who are deficient

While deficiencies are the greatest concern, it should be noted that supplementing with selenium has been shown to enhance immune functioning even in those with normal levels of this mineral in their blood. One such study showed that when people received an additional 200 mcg of selenium per day, the ability of the lymphocytes to kill tumors increased by 118%, and white blood cell activity increased by 82.3%! This research has experts theorizing that we need more selenium than even a “good” diet provides — making supplementation a must.

In conclusion

It looks like some of our super antioxidants, like Vitamins E and C, may have some pretty good competition with this well-documented trace mineral. With such a large array of benefits, it’s clear we’ll be hearing more about selenium and its potential to help keep our bodies healthy in the near future.



Reported intakes range from 200 mcg to 400 mcg daily.


Selenium can be taken with or without food, though when taken as part of a multivitamin formula, it is usually recommended with food. It should not be supplemented with large amounts of Vitamin C or trace minerals (especially zinc) as they may interfere with each other’s absorption.

Synergists of Selenium

Evidence has shown that combining selenium with Vitamin E results in significant synergistic antioxidant effects.

Methionine, an amino acid, is needed for both the absorption and use of selenium; therefore, it’s often suggested they be used together.

Toxicity of Selenium

Food or water containing 5 to 10 ppm (parts per million) of selenium, meaning over 1,000 mcg, may interfere with the sulfur levels in the body and may result in complications with teeth, hair, skin, nails, inflammation, nausea, and fatigue.

Bans and restrictions

None reported.


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  • Scott, R., et al., “The Effect of Oral Selenium Supplementation on Human Sperm Motility,” Br J Urol 82.1 (1998) : 76-80.
  • Tarp, U., “Selenium in Rheumatoid Arthritis. A Review,” Analyst 120.3 (1995) : 877-81.
  • Yoshida, M., et al., “An Evaluation of the Bioavailability of Selenium in High-Selenium Yeast,” J Nutr Sci Vitaminol 45.1 (1999) : 119-28.
  • Zamora, A.J., et al., “Mitochondria Changes in Human Muscle After Prolonged Exercise, Endurance Training and Selenium Supplementation,” Eur J Appl Physiol 71.6 (1995) : 505-11.