What is selenium?

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Selenium is a trace dietary mineral and non-metallic chemical element.

What is selenium?

Selenium is an element with atomic mass 78.96 and its atomic number is 34.
It is related to tellurium and sulphur and its chemical symbol is Se.
This mineral is found in soil and rocks in many allotropic forms and rarely occurs in nature in its elemental state. The most frequently encountered form is selenium dioxide (Se2).
In sulphide ores it occurs as pyrite and is also a primary byproduct in electrolytic copper refining.
This non-metal mineral is frequently used in electronic, glass, metal alloys and petrochemical industries.

Natural sources of dietary selenium

Most of the plant products contain this trace mineral and its dietary availability depends upon its concentration in the soil of the region.
It gets leached from soils in agricultural activities and becomes agricultural runoff.
Over some time such soils become deficient of this mineral and the plant produce also becomes deficient.

Selenium as an essential trace mineral

This trace mineral is essential in nutrition and the excess of it can be toxic.
Found in small amounts in all organs of human body, it is more concentrated in kidneys, liver, pancreas, spleen and testes.
This trace element, being a component of antioxidant enzymes, is essential for the formation of selenoproteins and enzymes like glutathione peroxidase.
Recommended dietary allowances (RDA) for adults is 55-60 μg/day.
A balanced diet may fulfill the RDA of this essential trace mineral.
Brazil nuts, whole grains, fish, shellfish and many fruits and vegetables are good sources of selenium.
People living in regions deficient in soil concentration of selenium and people with impaired gaotrointestinal system are likely to develop its deficiency.
As dietary supplements are available, its deficiency can be corrected.
Being toxic in high doses its supplementation should be monitored closely.
Selenium sulfide is a popular compound used in the treatment of dandruff and tinea versicolor.
It is believed that selenium may have a role in alleviating conditions in heart disease, thyroid gland disease and goiter, arthritis, HIV/AIDS and prostrate cancers. However further research studies are required for recommending dosage for treatments.
Related topics on selenium nutrition:
What is its role in human nutrition?
What are Health benefits?
What are deficiency symptoms?
What are its supplements? What is the dosage?
What is its toxicity, overdose and side effects?
What are good food sources?
What is selenium? (current topic)

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