Thomson CD, Chisholm A, McLachlan SK, Campbell JM. Brazil nuts: an effective way to improve selenium status. Am J Clin Nutr. 2008 Feb;87(2):379-84. PMID: 18258628
You need 55 microg/day
The minimum blood level is 1,27 micromol/l
one Brazil nut is around 50 microg
Selenium is an essential trace element. Its importance is underlined by the fact that it is the only trace element to be specified in the genetic code - as selenocysteine. Selenium is a key component of several functional selenoproteins [e.g., glutathione peroxidases (GPx), thioredoxin reductases, iodothyronine deiodinases and selenoprotein P] that protect tissues and membranes from oxidative stress and control the cell redox status. Evidence from in vivo and in vitrostudies suggests that selenium could enhance insulin sensitivity by mediating insulin-like actions.