Selenium and selenoproteins have a role to play in the protection of humans against viral infections [Méplan & Hughes 2020].
Viruses and viral infections are scary enough in and of themselves. Witness the effects of the current corona virus pandemic COVID-19.
Even more scary are the effects of nutritional deficiencies such as selenium deficiency on the body’s ability to fight off a viral infection.
Selenium Deficiency Associated with Increased Virulence of Viruses
Low selenium status, defined variously as serum selenium status below 70 micrograms per liter or below 85 micrograms per liter, is associated with the following deleterious effects of viral contagion [Méplan & Hughes 2020]:
- The viral pathogens induce oxidative stress by generating more harmful free radicals. The result is oxidative damage to cells, proteins, and DNA.
- The viral pathogens diminish the cells’ antioxidant defenses including diminishing the activity of the antioxidant seleno-enzymes, e.g. the glutathione peroxidases and the thioredoxin reductases.
- The viral pathogens increase oxidative stress to the extent that it can induce mutations of the genomes of the attacking virus. The result is that the mutated viruses are more virulent than the initial viruses were. This increased virulence of mutated viruses has been seen in both coxsackie viruses and influenza viruses. The consequence of the increased virulence is to make the viruses more dangerous even to people with adequate selenium status.
- The viral pathogens reduce the ability of the immune system to respond to the virus. This reduced immune response to viruses has also been seen in the response of selenium deficient humans to the HIV virus and the hepatitis B and C viruses.
Re selenium deficiency: Bomer et al reported more severe signs and symptoms of heart failure and poorer exercise capacity and poorer quality of life in heart failure patients with serum selenium concentrations below 70 mcg/L. Rayman reported that serum and plasma levels below 85 mcg/L are associated with decreased survival in HIV-infected patients [Bomer 2019; Rayman 2012].