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Nutrient - Nutrient focus on Selenium

By Debbie Paddington Dip ION

Selenium, an essential mineral, is found in trace amounts in the body and is most abundant in the liver, spleen, kidneys, pancreas and testes.  Vitamin E greatly enhances the effectiveness of selenium.

Functions of Selenium

  • Works as an antioxidant, especially when combined with vitamin E, by scavenging damaging particles in the body known as free radicals. Free radicals can damage cell membranes and DNA, and may contribute to ageing and a number of conditions, including heart disease and cancer. Antioxidants, such as selenium, can neutralise free radicals and may reduce or even help prevent some of the damage they cause.
  • Plays a major role in the synthesis and metabolism of thyroid hormones.
  • May help manage the body’s inflammatory response
  • Important for cardiovascular health
  • Helps promote healthy cholesterol levels
  • Can support  white blood cell production, enhancing the body's ability to fight illness and infection.
  • Formation and development of sperm
  • Important for the health of the prostate
  • Important for eye health
  • Deficiency Signs 

Selenium deficiency may contribute to heart disease, hypothyroidism, and a weakened immune system.  Early symptoms of a deficiency include muscle weakness and fatigue.

You may have low levels of selenium if you:

  • Smoke cigarettes
  • Drink alcohol
  • Take birth control pills
  • Have a chronic digestive disorder such as Crohn's disease or ulcerative colitis


It is difficult to get too much selenium from the diet, but in supplement form dosages over 900mcg can cause toxicity symptoms of which include nervousness, depression, nausea, vomiting and loss of hair and fingernails.

Food Sources

Brazil nuts, yeast, whole grains, wheat germ, fish (mackerel, tuna, halibut, herring) and shellfish (oysters, scallops, and lobster) are good sources of selenium. 

Selenium in the soil varies enormously around the world so the amount of selenium in different food does depend greatly on where it is grown. Selenium is also destroyed when foods are refined or processed so whole, unprocessed foods are better sources of selenium.

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