ABSTRACT
Dietary selenium (Se) is an essential mineral for both humans and animals. It functions as a component of several proteins, termed selenoproteins. These include glutathione peroxidases (GPx, several different isoforms), thioredoxin reductases (three isoforms), iodothyronine deiodinases (three isoforms), selenophosphate synthetase, selenoprotein P, and selenoprotein W (Burk and Levander, 2006). Because glutathione peroxidase and thioredoxin reductase function as antioxidants and because an inverse relationship between selenium intake and cancer risk was identi ed in several studies, increasing selenium intake has been proposed as a way to prevent the development of some forms of cancer in humans.
