Selenium - Nutrition Encyclopedia

Selenium in human metabolism

In addition, selenium is involved in thyroid metabolism; it is a component of enzymes that enable the conversion of thyroid hormone thyroxine into the biologically active form triiodothyronine. Furthermore, selenium binds certain heavy metals so they can cause less damage to body cells. For the immune system, selenium also plays an important role: It strengthens the immune defense. Good sources of selenium are offal, fish, meat, grains, nuts and legumes. The recommended daily intake for adults is between 30 and 70 µg. 50-90% of the selenium contained in food is absorbed into the body through the upper sections of the small intestine. Selenium is mainly excreted via urine. The body's selenium content is around 10-15 mg. Most of it is found in muscle tissue; however, liver, kidneys and heart also contain a lot of selenium.

Selenium Deficiency Symptoms

Deficiency symptoms: Selenium is only present in low concentrations in some soils; particularly sulfur dioxide-laden acid rain as well as sulfur-containing fertilizers contribute to plants taking up less selenium and more sulfur instead. In certain regions, a selenium deficiency can occur. Chronic diseases of the gastrointestinal tract as well as kidney insufficiency can also lead to a selenium deficiency. Patients receiving parenteral nutrition and alcoholics are also at risk. It is suspected that Keshan disease, a heart condition, and Kashin-Beck disease, a joint disorder, may be due to selenium deficiency.

Symptoms of selenium deficiency include changes in nails and less pigmentation of hair. It is suspected that selenium deficiency can also contribute to the clouding of the lens. A lack of selenium can be determined through blood tests. It is debated whether the administration of selenium might possibly be helpful for diseases of rheumatic nature. Selenium has a protective effect against cancer.

Overview of Trace Elements