High Selenium Intake could be Harmful

It has been found that a high intake of selenium could have negative effects on health and can lead to an increased risk of the development of Type 2 Diabetes.

A recent review of a paper published Online First in the Lancet discusses the potentially harmful effects excess dietary selenium could have on health.

Whilst having an adequate selenium intake is beneficial, for those who take additional supplements or have a high intake, selenium could have negative effects on health and can lead to an increased risk of the development of Type 2 Diabetes.

Selenium is a naturally occurring element that can be found in trace amounts in a variety of foods including Brazil nuts, tuna and eggs.

The selenium content of food depends on the levels of the mineral that can be found in the soil.

Professor of Nutritional Medicine at the University of Surrey, Margaret Rayman who gained a doctorate in organic chemistry from the University Oxford states:  “The intake of selenium varies hugely worldwide.  Intakes are high in Venezuela, Canada, the USA, and Japan, but lower in Europe.”

Selenium is essential and low levels have been shown to lower immune function and decrease cognitive function.

On the other hand, levels within the therapeutic range have been linked to a number of benefits including improved male fertility and protection against some cancers like those of the lung, bladder and prostate.

The use of selenium supplements has increased over the past decade due to beliefs about its health benefits.

However, there have been mixed results from studies trying to confirm these theories.

The Review on the Lancet paper shows how the results from trials vary depending on the selenium status of a population as well as their genetic background.

Professor Rayman explains that the results show that taking selenium supplements is only beneficial when normal intake is insufficient.

Most of the trials relating to supplementation have been carried out in populations that have adequate intake such as the USA and Professor Rayman believes more studies need to be carried out on populations with lower intakes such as Europe.

The Review also presents the idea that there may be a link between a person’s genetics and the level of positive effect supplements could have.