Selenium is now regarded as an essential trace element in humans and animals as selenium is found in increasingly lower quantities in parts of the earth's surface and soil in which our foods grow. Selenium toxicity has been noted in areas where selenium content of the ground is high, but selenium deficiency is a far more widespread problem - contributing to Infertility, heart problems, eye disease and premature aging.

Selenium carries out its main functions as part of our main antioxidant systems. Glutathione peroxidase is an antioxidant that protects intracellular structures against oxidative damage by free radicals. Selenium is also known to have a role in the following:

Normalisation of liver function.

Antioxidant protection of major body cells.

Maintenance of a healthy heart and vascular integrity.

Detoxification of heavy metals such as arsenic, cadmium, mercury and lead.

Production of beneficial anti-inflammatory prostaglandins.

Production of thyroxine hormone.

Deficiency signs and symptoms
Selenium deficiency has traditionally occurred in areas where the soil is particularly low in this mineral. However, as modern lifestyles have allowed us to eat foods from very many different countries of origin, true selenium deficiency has become less of a problem.

One selenium deficiency disease is known as Keshan's disease - after the province in China that has the lowest soil selenium levels in the world. Symptoms are mainly to do with the heart - specifically involving wastage of the heart muscle. Another selenium deficiency disease is known as Kaschin-Beck disease, and affects the cartilage in the joints.

Individuals who may benefit from selenium supplementation
The groups of people particularly found to be at risk of selenium deficiency are as follows:

Vegetarians

The elderly

Pregnant and nursing mothers

Smokers

Rheumatoid arthritis sufferers

Any of the above groups may benefit from additional selenium in the form of supplement, although efforts should also be taken to improve the diet as well.