Selenium Benefits and Side Effects: Can Your Multi-Vitamin Cause Diabetes?

by Cindy

Selenium Benefits & Side Effects

Nutritional supplements
Creative Commons License photo credit: Clean Wal-Mart
Can your multi-vitamin cause diabetes? Maybe!  In recent months, multi-vitamins and supplements have gotten bad press as some research studies have linked the use of these substance to poor outcome and an increased risk of death in certain patients.  One component of many multi-vitamins that has come under fire in recent years is selenium.  Selenium is a mineral that is needed for normal body processes but only in tiny amounts.  This mineral is found in many of the foods that we eat.  Once consumed, the body uses selenium to scavenge free radicals that can cause damage to the cells in the body.  Many people take selenium for this reason as the perceived benefits of selenium supplements include prevention of cellular damage and possibly cancer by destruction of free radicals.  

What is Selenium?

The average adult only needs small amounts of selenium.  The recommended daily allowance (RDA) is only 55 micrograms per day.  Most people can easily meet their daily selenium needs with a normal, healthy diet.  Food from plant sources, such as rice and nuts, contain selenium but the amounts that are present in these foods depends largely on the amount of this mineral that is present in the soil where the food was grown.  There are also selenium supplements that are available for purchase.  The majority of these supplements are available in 100 to 200 microgram formulations.  In addition, selenium is often found in daily multi-vitamins with the amounts varying from 55 to 200 micrograms per tablet.  This means that your diet may contain too much of this mineral. 

Selenium Benefits

Many people take selenium because studies have shown that a selenium supplement benefits patients because they can improve health in the following ways:

  • Reduce the risk of certain types of cancer
  • Reduce the risk of skin cancer recurrence
  • Lower the risk of heart disease
  • Improve symptoms of rheumatoid arthritis

Selenium Side Effects

However, recent studies have suggested that too much selenium can actually be harmful.   Consuming too much selenium every day can lead to health problems from overdose of this mineral.   This condition is known as selenosis and patients taking more than 400 micrograms of selenium per day are at an elevated risk for developing this condition.  In addition, too much selenium has recently been linked to an increased risk for developing diabetes!

Selenium and Diabetes

A recent review of available scientific research has shown that consuming too much selenium raises the risk of developing type 2 diabetes.  It was concluded that the American diet provides the average adult with the right amount of selenium and that additional supplementation is not necessary.  This means that the amount of selenium that is present in many daily multi-vitamins is not necessary for most adults. Although several studies have shown that people with too little selenium in their diets do benefit from taking a supplement, other studies have suggested that supplementation does cause harm.

A study of approximately 1,200 research participants showed that people taking 200 micrograms of selenium increased their risk of developing diabetes by up to 3 times in certain patients.  In addition, data from the CDC also suggests that there may be a link between the development of diabetes and excessive selenium intake.  Other studies have correlated hyperglycemia with elevated concentrations of selenium in the blood.

Between normal dietary intake and a daily multi-vitamin, many Americans may be getting too much selenium which possibly could raise the risk for the development of diabetes.  For many people, the risk of developing diabetes is also quite high, particularly for those who are already considered pre-diabetic.   You may wish to review the contents of your daily multi-vitamin with your physician at your next visit to be sure that your supplements are not potentially causing more harm than good.

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