Selenium: An element with the atomic symbol Se, atomic number 34, and atomic weight 78.96. It is an essential micronutrient for mammals and other animals but is toxic in large amounts. Selenium protects intracellular structures against oxidative damage. It is an essential component of GLUTATHIONE PEROXIDASE.Selenomethionine: Diagnostic aid in pancreas function determination.Glutathione Peroxidase: An enzyme catalyzing the oxidation of 2 moles of glutathione in the presence of hydrogen peroxide to yield oxidized glutathione and water. EC 220.127.116.11.Selenoproteins: Selenoproteins are proteins that specifically incorporate SELENOCYSTEINE into their amino acid chain. Most selenoproteins are enzymes with the selenocysteine residues being responsible for their catalytic functions.Selenoprotein P: An extracellular selenoprotein that contains most of the SELENIUM in PLASMA. Selenoprotein P functions as an antioxidant and appears to transport selenium from the LIVER to peripheral tissues.Organoselenium Compounds: Organic compounds which contain selenium as an integral part of the molecule.Selenic Acid: A strong dibasic acid with the molecular formula H2SeO4. Included under this heading is the acid form, and inorganic salts of dihydrogen selenium tetraoxide.Selenium Radioisotopes: Unstable isotopes of selenium that decay or disintegrate emitting radiation. Se atoms with atomic weights 70-73, 75, 79, 81, and 83-85 are radioactive selenium isotopes.Selenious Acid: A selenium compound with the molecular formula H2SO3. It used as a source of SELENIUM, especially for patients that develop selenium deficiency following prolonged PARENTERAL NUTRITION.Selenocysteine: A naturally occurring amino acid in both eukaryotic and prokaryotic organisms. It is found in tRNAs and in the catalytic site of some enzymes. The genes for glutathione peroxidase and formate dehydrogenase contain the TGA codon, which codes for this amino acid.Selenium Oxides: Inorganic compounds formed through the oxidation of selenium.Nails: The thin, horny plates that cover the dorsal surfaces of the distal phalanges of the fingers and toes of primates.Trace Elements: A group of chemical elements that are needed in minute quantities for the proper growth, development, and physiology of an organism. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Vitamin E: A generic descriptor for all TOCOPHEROLS and TOCOTRIENOLS that exhibit ALPHA-TOCOPHEROL activity. By virtue of the phenolic hydrogen on the 2H-1-benzopyran-6-ol nucleus, these compounds exhibit varying degree of antioxidant activity, depending on the site and number of methyl groups and the type of ISOPRENOIDS.Dietary Supplements: Products in capsule, tablet or liquid form that provide dietary ingredients, and that are intended to be taken by mouth to increase the intake of nutrients. Dietary supplements can include macronutrients, such as proteins, carbohydrates, and fats; and/or MICRONUTRIENTS, such as VITAMINS; MINERALS; and PHYTOCHEMICALS.Selenium-Binding Proteins: A group of proteins that covalently attach to selenium or SELENIUM-containing compounds.Thioredoxin-Disulfide Reductase: A FLAVOPROTEIN enzyme that catalyzes the oxidation of THIOREDOXINS to thioredoxin disulfide in the presence of NADP+. It was formerly listed as EC 18.104.22.168Diet: Regular course of eating and drinking adopted by a person or animal.Yeast, Dried: The dry cells of any suitable strain of SACCHAROMYCES CEREVISIAE or CANDIDA. It can be obtained as a by-product from the brewing of beer or by growing on media not suitable for beer production. Dried yeast serves as a source of protein and VITAMIN B COMPLEX.Antioxidants: Naturally occurring or synthetic substances that inhibit or retard the oxidation of a substance to which it is added. They counteract the harmful and damaging effects of oxidation in animal tissues.Iodine: A nonmetallic element of the halogen group that is represented by the atomic symbol I, atomic number 53, and atomic weight of 126.90. It is a nutritionally essential element, especially important in thyroid hormone synthesis. In solution, it has anti-infective properties and is used topically.Spectrophotometry, Atomic: Spectrophotometric techniques by which the absorption or emmision spectra of radiation from atoms are produced and analyzed.Selenoprotein W: A single SELENOCYSTEINE containing protein that binds reduced GLUTATHIONE and can act as an antioxidant.Isotopes: Atomic species differing in mass number but having the same atomic number. (Grant & Hackh's Chemical Dictionary, 5th ed)Deficiency Diseases: A condition produced by dietary or metabolic deficiency. The term includes all diseases caused by an insufficient supply of essential nutrients, i.e., protein (or amino acids), vitamins, and minerals. It also includes an inadequacy of calories. (From Dorland, 27th ed; Stedman, 25th ed)White Muscle Disease: A myodegeneration most frequent in calves and lambs whose dams have been fed during gestation or longer on feeds, especially legumes (FABACEAE), grown in certain areas where selenium is either deficient or unavailable in the soil. It has been recorded in many countries. It has been produced experimentally in several species of animals on low-selenium intake. A similar myopathy occurs naturally in goats, deer, foals, and dogs but proof of the etiology is lacking. (Merck Veterinary Manual, 5th ed)Nutritional Status: State of the body in relation to the consumption and utilization of nutrients.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.