Selenium (Mineral Supplement)
Selenium is a trace element found throughout the body but which is most abundant in the kidneys, liver, spleen, pancreas and testes. This antioxidant mineral is a component of the enzyme glutathione peroxidase which helps protect cells against damage from free radicals.
Selenium helps protect the cardiovascular system by reducing the risk of blood clotting and by increasing the ratio of ‘good’ to ‘bad’ cholesterol. It may be useful in the prevention of cataracts and macular degeneration in later life and, in combination with Vitamin E, has an anti-inflammatory action.
Selenium is vital for normal sexual development, regulates prostaglandin production and is necessary for the formation of the active form of thyroid hormone. It promotes healthy immune function as it is involved in the production of antibodies and also stimulates increased antibody response to infection. Research has shown that it may have a role in fighting the virus responsible for cold sores and shingles.
The selenium content of the human body is believed to be 13–20 mg. The recommended daily intake in order to maintain healthy levels is 75 µg for men and 60 µg for women. The richest dietary sources include offal, seafood, wholegrains, brazil nuts, avocado, lentils and dairy products. The selenium content of vegetables and grains depends on the amount of the mineral in the soil in which they were grown.
Selenium deficiency is rare in otherwise healthy individuals but can occur in people with compromised intestinal function or those dependent on food grown in selenium-deficient soil. Increased oxidant stress due to Vitamin E deficiency may also be a factor. Deficiency may lead to stunted growth, delayed sexual development and reduced fertility.
Although selenium is an essential trace element, it is toxic if taken in excess. Excessive intake may lead to selenosis which can cause depression, irritability, nausea, skin discolouration, hair loss, changes in the nails a smell of garlic on the breath and urine, and neurological damage.
NB You should always seek professional advice before taking mineral supplements.