• Selenium was found to prevent liver cell necrosis & muscular dystrophy.
• Total body content of selenium around 10 mg and it is present mainly in liver.
• Richest sources are meat, sea foods, liver,
kidney and grains.
• 50 to 200 μg/day.
Absorption and excretion
• Selenium is absorbed mainly from the duodenum.
• Selenium after absorption is transported bound to plasma proteins particularly β- lipoproteins in humans.
• Main route of excretion of selenium appears to be through urine.
• Selenium, as selenocysteine is an essential component of the enzyme glutathione peroxidase.
• Glutathione peroxidase functions as an antioxidant enzyme.
• It suppresses the oxidative stress by converting oxygen free radicals into less toxic forms or non-toxic forms.
• The presence of selenium in the diet reduces the requirement of vitamin E, since vitamin E also acts as an antioxidant.
• Selenium may exert anticancer effects because of its antioxidant role.
• Selenium containing enzyme 5’deiodinase converts thyroxine (T4) to triiodo-thyronine (T3) in thyroid gland.
• In selenium deficiency, conversion of T4 to T3 is
impaired resulting in hypothyroidism.
• Selenium binds with certain heavy metals & protects body from their toxic effects.
• Selenocysteine is considered as 21st standard amino acid since it is coded by UGA, which is a termination codon.
• Selenium is incorporated to proteins as selenocysteine during protein synthesis.