Selenium is the trace and essential mineral of the body. It is required in the body in small amount but perform functions bigger than its amount.
Its dietary sources are both from plants and animals;
- Plant Sources: These include Brazil nuts, cereals mushrooms, brown rice, garlic and whole wheat bread.
- Animal sources: These include liver, fish such as salmon fish, shrimp, meat, beef, kidney and brewer’s yeast along with milk, egg, and poultry.
- Selenium is a part of the Schwarz’s factor 3, which like vitamin E is very important for the body and gives protection against hepatic necrosis. Both these are important for each other since they both tend to increase and enhance the functions of each other.
- It is very effective in that it will exert its beneficial effect when it is present as 2 parts per 1,000,000,000 of the diet.
- Selenium has been found to possess antioxidant properties as it is an integral component of glutathione peroxidase. This enzyme is essential in catalyzing reactions that are necessary for the removal of toxic peroxides. This enzyme is also an important part of immunity system. It is also involved in the coagulation system of blood.
- It is effective against osteoporosis
- It is seen to regulate the level of serum cholesterol.
- In experimental animal selenium has found to give protection against several carcinogens, chemical as well as viral.
- It also binds cadmium, mercury and other metals and thus gives protection against their toxic effects.
- Selenium administered in the children suffering from kwashiorkor results in significant weight increase.
- Selenium supplements are now available and are used in treating growth related problems as well as anemia.
After absorption selenium interacts with the sulphur containing amino acids such as cysteine and methionine and forms the enzyme glutathione peroxidase, and then incorporates into many proteins, such as myoglobin and hemoglobin. Good absorption is dependent on the dietary selenium to sulphur ratio.
- Clinically its deficiency produces Keshan diseases, a disease which was once endemic in Keshan the province of china where selenium might be deficient in the soil of china. The clinical findings in this disease are found to be arrhythmias and cardiogenic shock as well as peripheral myopathies may also be seen. Children and women of child-bearing age are particularly susceptible to this disease.
- If selenium is not in adequate amount, antioxidation will not take place and chances of premature aging may increase.
- Poisoning of metals can occur due lack of it in the body.
- Skin and hair growth will be effected due its deficiency.
- Immunity will be affected since there may be decreased production of white blood cells take place as a result of its deficiency.
Selenium toxicity can occur after ingestion of water containing large amount of the metal. If its levels are high, it is excreted in the urine. The clinical finding are de-pigmentation of skin, hair loss, weariness, abnormal nails, a garlic like odor from the breath even without garlic ingestion are the signs or the indication toxicity of selenium.