What is it?
Selenium is a trace mineral.
What it does
The body requires only small amounts of selenium. Selenium is an anti-oxidant that helps with immunity and protects cells.
Some research suggests that selenium may help in the treatment of AIDS. 
Selenium can be found in whole grain foods, dairy products, meat, fish, poultry and other foods rich in protein.
Recommended Dietary Allowance (RDA)
Canada’s RDA can be found at here.
Molecular Dosage Range
Depending on individual circumstances, orthomolecular practitioners may recommend dosages higher than the RDA, in some cases much higher.
 Foster HD. How HIV-1 causes AIDS: Implications for prevention and treatment,” Medical Hypotheses, Vol. 62(4), p 549-553, 2004.