Selenium is needed, amongst other things, for:
- Anti-oxidant, see Thyroid
- Conversion of T4 to T3, see Thyroid
- Being an important part of glutathione
200 mcg per day of selenomethionine usually suffices. I found that, with my mercury toxicity, selenium yeast was very helpful.
Sulfur (S) protects from selenium toxicity.
It should be noted that selenium does protect tissues from the toxic effects of heavy metals, but excretion of toxic heavy metals are not increased by selenium therapy. Selenium apparently binds these metals, such as mercury and cadmium, rendering them less damaging to cells and tissues.
Fluorine (F) has been shown to counteract the effects of selenosis. This has been found in areas with high levels of both selenium, and fluorine. Selenium was not toxic even with a high body burden when fluorine was also present.
On the basis of TMA studies it is suspected that selenium is antagonistic to magnesium. This is due to the potential sodium raising effect of selenium. Sodium increases the excretion of magnesium. Magnesium is also essential for the synthesis of glutathione, and a deficiency can increase the effects of selenium toxicity.
Antagonism of lead (Pb), tin (Sn), and zinc (Zn) has been sited by Schrauzer. More recent investigations have confirmed the zinc-selenium antagonism. Copper (Cu) has also been shown to be a selenium antagonist.
The possibility of iron, and manganese antagonism by selenium also exists. Anemia is a consistent finding in animals, and humans with selenium toxicity.
Animals suffering from selenosis were found to have decreased levels of vitamin A, and ascorbic acid. Ip, reported that the protective effect of selenium on mammary carcinoma in animals was nullified by high vitamin C supplementation. Selenium toxicity in laboratory animals is associated with a corresponding decrease in the levels of vitamin C, and vitamin K. The nutrients shown in figure 1 and 2, can be antagonized by excessive selenium accumulation. They in turn can inhibit the toxic effects of selenosis.
Once I stopped the selenium, symptoms were gone within a few days.
Handy overview of dangers of selenium toxicity and symptoms:
A thorough overview of selenium: