Selenium is an essential micronutrient. Humans cannot synthesize it. Therefore, we must get it from our diets. The selenium content of our diets depends on the richness or poorness of the selenium in the soil and the food. In fact, there are surprisingly large differences in selenium content in various regions of the world [Zhang 2020a].
Selenium through its incorporation into 25 known selenoproteins is necessary for a range of biological functions. Zhang et al [2020a] list the following biological functions of selenium and selenium-derived selenoproteins:
- Antioxidant function
- Anti-inflammatory function
- Anti-viral function
- Cellular redox function
- Immune cell function
- Protection of the cardiovascular system
Selenoprotein Functions Relevant to Viral Infections
Selenium and selenium-derived selenoproteins such as the glutathione peroxidases (GPXs), the thioredoxin reductases (TXNRDs), and the endoplasmic-reticulum-associated selenoproteins influence viral pathogenicity. Among other things, these antioxidant selenoenzymes reduce the extent of oxidative stress generated by viral pathogens. Failure to counteract oxidative stress can result in mutations in the viral genome from benign to highly virulent strains [Zhang 2020a].