All About Selenium

SELENIUM is a micro mineral. It is found in Meat, eggs, milk, seafood and whole grain cereals are some good sources of selenium. It is very important in the diet as it plays the role as prosthetic group of the enzyme glutathione peroxidase which acts as an anti-oxidant and prevents the harmful effect of certain chemicals and free radicals. The major function of the enzyme is to reduce hydro peroxides. It is seen that Vitamin E and selenium works synergistically to prevent oxidation of the cell membrane. In the adult human, body selenium ranges from 3-14.6mg, the lower ranges being encountered in selenium deficiency.

Selenium deficiency

Selenium deficiency is relatively rare in healthy well –nourished individuals. It can occur in patients with severely compromised intestinal function, total parenteral nutrition, and mal absorption, in Protein Energy Malnutrition, cardiovascular diseases, and cancer. It is observed that Selenium deficiency also impairs thyroid hormone synthesis. Selenium deficiency in combination with coxsackievirus infection can lead to keshan disease, which is potentially fatal. Selenium deficiency also contributes (along with iodine deficiency) to kashin – beck disease.

Keshan disease

It is a type of selenium deficiency. An endemic cardiomyopathy (affects mainly children) , widely distributed in china. The occurrence of this disease has marked seasonal fluctuation, more cases appearing during winter in the north and during summer in south. Characterized by acute or chronic cardiac insufficiency, heart enlargement, gallop rhythm (indicator of heart abnormality), arrhythmia and ECG Changes. This disease is classified as acute, sub –acute and chronic (low output pump failure) and latent form (normal heart function, but mild enlargement)

Kashin-beck disease

It can be called an endemic osteo-arthropathy seen in Siberia and certain parts of china. The disease is characterized by chronic disabling and osteo-arthrosis in children (5-13 years). The symptoms include general limb weakness, joint stiffness and bending of finger joints with pain in knee and ankle joints. In severe cases, leads to shortening of fingers and longer bones with enlargement and dysfunction of the junctions with growth retardation.

Selenium and cardiovascular disease

This is also a selenium deficiency disease characterized by low serum selenium. The people are at higher risk of coronary artery disease. Further free radicals have been implicated in initiation and progression of arteriosclerosis therefore selenium along with other antioxidants protects the arterial wall from oxidative damage.

How to prevent the deficiency?

Safe and adequate intake is between 50 – 200microg per day for adults. RDA is around 60-70 micrograms/day and recommended daily intakes are 70ug/day. An additional allowance of 10-15 micrograms/day required during pregnancy and lactation.