The Irony of Selenium: Toxic yet Essential for Life

The animals. Selenium appears as a bystander mineral in plants and terms to be poisonous in feed. Plants use selenium as protective agent from the harm of being eaten by animals but plants like locoweed necessitates selenium for their growth in the soil. Selenium is an element constituted of amino acids like selenocysteine and selenomethionine. Human bodies have the presence of the trace element selenium and it performs functions of cofactor for reduction of antioxidant enzymes called gluthathione peroxidases. Thioredoxin reductase is an antioxidant enzymes present in animals, plants and this enzyme is found in all living organisms. Selenium micronutrient is not required for all the plants.

Selenium is termed to an essential element but considered to be poisonous on excessive consumption. The exceeding of the Tolerable Upper Intake Level of 400 micrograms leads to selenosis. The symptoms for selenosis include garlic odors in the breath, hair loss, gastrointestinal disorders, fatigue, irritability and neurological damage. Extensive selenosis ends in the cirrhosis of the liver, pulmonary edema and death.

Good sources of selenium are available from cereals, nuts, eggs and fish. The Brazil nuts have rich source of selenium. High quantities of selenium are found in kidneys, meats, crab and lobster.

Due to the low existence level of elemental selenium and metallic selenide they have low quantity of toxication. In contrast, selenate and selenite are very deadly and their actions are compared with the toxic of arsenic. Hydrogen selenide is very poisonous and has a corrosive gas. The presence of selenium can be found in organic compounds like dimethyl selenide, selenomethionine, selenocysteine and methylselenocysteine and they have large amounts of toxicity. The nano-size selenium has less toxic content. The presence of the deficiency of selenium is very exceptional in the healthy individuals. The deficiency arises to patients have severe intestinal function and undertaking of potential nutrition. Foods produced from the selenium deficient soil is also to the prone of deficiency in selenium. Suggested intake of selenium quantity for an adult is 55mg per day as recommended by the Dietary reference intake.

The deficiency of selenium leads to the Keshan disease and promotes to the death of an individual. This deficiency also paves way for the disease of Kashin-Beck disease. The symptoms for the Keshan disease are weakening of the heart and myocardial necrosis. This disease causes illness to the body, biochemical reactions and infectious diseases. The symptoms for Kashin-Beck disease are degeneration, atrophy and necrosis of cartilage tissue. These diseases are found more common in China because of the deficiency in the soil for the chemical selenium. Researches in the Jiangsu Province of China have proved that the consumption of selenium rich supplements leads to the eradication of the diseases.

Selenium is also considered essential for the transformation of the thyroid hormone called thyroxine (T4) and this leads to the existence of diseases like hypothyroidism, extreme fatigue, cretinism and recurrent miscarriage.