Facts about Selenium

Selenium is a chemical element (atomic number 34, atomic mass 78.96 amu) belonging to the sulfur group of non-metallic elements. It is represented by the chemical symbol Se. The word selenium is derived from the Greek word selene, which means 'moon'. It was Jöns Jacob Berzelius who discovered this element in 1817. Selenium occurs in several forms, out of which crystalline hexagonal form is the most stable. Almost 21 isotopes of selenium have been discovered so far.

Some Facts about Selenium

Since, selenium is a non-metallic element, it is not a very good conductor of heat and electricity. However, it is found to demonstrate photovoltaic action (it can produce electricity when exposed to light). Selenium is a photoconductive substance, i.e. its electrical conductivity changes with the absorption of electromagnetic radiation or light. Generally, in case of photoconductive substances, resistance to flow of electricity decreases with the increase in illumination.

Selenium has wide-ranging applications, both in the industrial field, as well as in the field of medicine. It is commonly used in TV cameras, photographic equipment and in xerography or electrophotography. It is also used in glass industry to produce red colored glass as well to remove the color of a glass. Selenium is widely used in rectifier, an electrical device which can convert alternating current (AC) into direct current (DC). It has also found application as an additive, in the production of stainless steel.

Besides its industrial applications, selenium is also well-known for its medicinal uses. Selenium, like vitamin E is an antioxidant, and is required as a trace element, by most of the animals including humans. It is found to be effective in the treatment of heart diseases. Selenium is needed in the human body, for the production of an important antioxidant called glutathione peroxidase. Due to its antioxidant properties, it prevents oxidization and thereby protects cells and tissues from free radicals. It also assists the immune system by stimulating the production of white blood cells. However, selenium is required only in its elementary form, as many of its compounds are toxic or poisonous.

Selenium has the ability to detoxify the body from toxic metals like mercury and arsenic. Due to its antioxidant properties, it is found to slow down the process of aging, and maintain elasticity of the tissues. Selenium can prevent viral replication and hence, is effective in controlling viral infections. Because of this, it is thought to be beneficial in slowing down the advancement of the disease HIV/AIDS. Besides, it has anti-inflammatory property, and therefore may be used to reduce the pain and stiffness experienced by arthritis patients.

People suffering from selenium deficiency are at a greater risk of asthma, cataract, enlargement of the heart, sterility, herpes, arthritis, muscular weakness and weakened immune system. Moreover, its deficiency can also increase the risk of cancer and cardiovascular diseases. Some significant sources of this important element include lobster, oyster, tuna, mackerel, eggs, chicken, beef, fish, mushrooms, broccoli, oatmeal, garlic, sesame seeds, etc. Besides, supplements of selenium are also available in the market.

However, it should be kept in mind that the body requires selenium in very small or trace amounts and large amounts of this element can be toxic. Excessive selenium in the body may cause nerve damage, hair loss, weakness, liver damage, nervousness, nausea, stomach and nail problems.