Trace element :Selenium

ELENIUM
SOURCES OF SELENIUM
  • Seafoods and organ meats are the richest food sources of selenium .
  • Other sources include muscle meats, cereals and other grains, and dairy products.
  • The amount of selenium in drinking water is not nutritionally significant in most geographic regions .
  • The amount of selenium in a given type of plant-based food depends on the amount of selenium in the soil and several other factors, such as soil pH, amount of organic matter in the soil.
RECOMMENDED DIETARY ALLOWANCES(RDAs) FOR SELENIUM
Age Male Female Pregnancy Lactation
Birth to 6 months 15 mcg 15 mcg
7–12 month 20 mcg 20 mcg
1–3 years 20 mcg 20 mcg
4–8 years 30 mcg 30 mcg
9–13 years 40 mcg 40 mcg
14–18 years 55 mcg 55 mcg 60 mcg 70 mcg
19–50 years 55 mcg 55 mcg 60 mcg 70 mcg
51+ years 55 mcg 55 mcg
DEFICIENCY OF SELENIUM:
  • Selenium deficiency causes cardiomyopathy.
  • Keshan disease is an endemic cardiomyopathy found in children and young women residing in regions of China where dietary intake of selenium is low. Kashin-Beck disease - endemic osteoarthritis in preadolescents in China. 
EXCESS OF SELENIUM
  • General: Alopecia, abnormal nails, garlic odor to breath,dermatitis
  • Occupational: lung and nasal cancer, liver necrosis

BIOLOGICAL FUNCTIONS OF SELENIUM:
  • As an Antioxidant:Glutathione peroxidase contains selenium as a prosthetic group. In erythrocytes and other tissues, it catalyses the destruction of hydrogen peroxide and lipid peroxidase, protecting membrane lipids and hemoglobin against oxidation.
  • Role in thyroid hormone production:Selenium is a trace element that plays a role in thyroid hormone production, as it forms part of a seleno-enzyme responsible for converting T4 into T3.
  • Hypothyroidism in Himalayan region is associated with Iodine Deficiency and Selenium deficiency.
  • Acts in synergism with Vitamin E and prevents hepatic necrosis and muscular dystrophy
Exam Question
  • Selenium sulfide is indicated for treating Tinea Versicolor.
  • Sunflower seeds are good source of B complex vitamins,Vitamin E ,Selenium.
  • Biological antioxidants which act against the free radicals formed inside the body are Selenium, Uric acid ,vitamin E, Ascorbic acid,Ubiquinone and carotenes .
  • Selenium act as a cofactor for enzyme Glutathione peroxidase.
  • Selenium deficiency causes cardiomyopathy.
  • Keshan disease is caused due to deficiency of Selenium.
  • Hypothyroidism in Himalayan region is associated with Iodine Deficiency and Selenium deficiency.
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