What is it?
Selenium is a mineral that can be obtained from food like crab, wheat , fish, liver and poultry. It is also found in water. Selenium is essential for the body processes and also to increase the action of anti-oxidants.
There are ongoing research conducted to prove that selenium is useful for those who have selenium deficiency, improves thyroid disorder like hashimoto's thyroiditis and reduce bad cholesterol.
More randomized controlled research studies need to be conducted to prove other proclaimed benefits.
Possible side effects
At normal dosing it is safe for most people when taking less than 400 mcg daily over a short period of time. Doses above that can cause selenium toxicity with symptoms like hair loss, nail inflammation, fatigue, white horizontal streaking on fingernails, nausea, vomiting, irritability, garlic breath odor and a metallic taste. Other possible side effects are lightheaded, facial flushing,tremor, blood clotting problems, muscle tenderness, liver and kidney problems.
Pregnant and lactating woman can take selenium at dosing less than 400 mcg daily. Anything above that level is unsafe. Children can take selenium but at lower doses.
Selenium may affect the motility of sperm hence it may reduce men's fertility.
Selenium supplementation may worsen hypothyroidim which is associated with iodine deficiency.
Selenium may increase the risk of bleeding hence it should be stopped at least two weeks before any surgery.
Cholesterol medications: selenium may reduce the effectiveness of cholesterol lowering drugs like statins and niacin.
Barbiturates (sedative medications: as selenium may slow down the break down of barbiturates, it will increase the risk of the side effects of these sedative medications.
Anti-platelet/ anti-coagulant: Selenium when taken with these drugs which slows blood clotting , will attenuate its effects and increases risk of bleeding.
The daily recommended dietary allowances (RDAs) of selenium are:
The tolerable upper limit is: