Selenium and Selenoproteins and Viral Infections

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].

Woman sneezing
Selenium deficiency and reduced selenoprotein expression have been associated with the pathogenicity of several viruses.

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]. read more

Selenium and Mitochondrial Disorders and Telomere Attrition

Selenium supplements may be beneficial as an adjuvant treatment for patients with mitochondrial disorders. This is especially true in many parts of Europe and the Middle East where the soil and the foodstuffs have poor selenium content [Stoffaneller & Morse 2015]. Specifically, individuals with mitochondrial dysfunction need the antioxidant and anti-inflammation effects of selenium-dependent selenoproteins [Alehagen 2021; Opstad 2022].

Prof Jan Aaseth
The mitochondria are the organelles in our cells that generate the ATP energy that our cells need to function. They are our essential mini power plants. However, mitochondrial dysfunction is associated with generation of toxic oxygen, telomere shortening, cell death, and biological aging. Pictured: Prof. Jan Aaseth, MD, PhD, Innlandet Hospital & Inland Norway University of Applied Sciences.

Mitochondrial dysfunction can be defined as the diminished capacity of the mitochondria in the cells to convert sugars into energy, i.e., the diminished capacity of the cells to generate ATP energy [Miwa 2022].

Mitochondrial dysfunction is closely associated with biological aging and with cell senescence (the cessation of cell division) [Miwa 2022]. read more

Selenium Status and Immune Function

Selenium is one of the micronutrients known to have an important and specific impact on immune system activity.

T-helper cell
Administration of selenium enhances the immune response of T-helper 1 cells and the stimulation of T cells. Depicted here: T-helper cell. Selenium also acts as a co-factor to achieve a more effective immune response to COVID vaccination.

In a 2022 review, Munteanu and Schwartz summarize the relevant research data on the modulation of immune function by micronutrients, including selenium and zinc [Munteanu 2022].

For selenium, the authors find the following evidence of a beneficial effect of selenium on immune system function:

  • Selenium, as a component of the amino acid selenocysteine, improves the synthesis of inflammatory mediators.
  • Selenium treatment leads to a decline in the gene expression of the pro-inflammatory cytokines IL-1 and TNF-alpha. This indicates that selenium has an anti-inflammatory effect in the body.
  • Selenium enhances the immune response of T-cells and T-helper 1 cells. T-cells work to destroy cells that have been infected by bacteria or viruses. Th1 cells are also responsible for fighting against bacteria and viruses.
  • Selenium supplementation increases the concentration of antibodies that enhance vaccine effects.
  • Selenium acts as a co-factor in the immunity that is mediated by the influenza vaccine. Selenium also serves as a co-factor to achieve a more effective immune response to COVID vaccination.
  • Selenium contributes to the defense against bacterial and vital pathogens through its effects on redox signaling activities.
  • -Selenium supplementation of patients with cancer increases antibody concentrations of the immunoglobulins IgA and IgG as well as increases the number of neutrophils.

Selenium – A Crucial Micronutrient for a Functional Immune System

Munteanu & Schwartz [2022] make the following additional points about an adequate supply of selenium:

  • Selenium improves not only in the functioning of the immune system but also the functioning of thyroid metabolism and the functioning of the cardiovascular system.
  • Selenium may play a role in the prevention of some forms of cancers.

Selenium and COVID-19

Munteanu & Schwartz [2022] report that selenium together with zinc exerts a protective role in COVID-19 patients. The combination of selenium and zinc is associated with a higher chance of survival. read more

HIV Infection and Selenium Supplementation

HIV infection is associated with a higher risk of tuberculosis and death.  Selenium deficiency is associated with an increased risk of HIV infection. Several trials have shown that selenium supplementation of patients with HIV is associated with beneficial outcomes [Muzembo 2022].

HIV symptoms
HIV = human immunodeficiency virus.

Muzembo et al conducted a systematic review of six randomized controlled trials of selenium supplementation of HIV-infected patients. They reached the following conclusions [Muzembo 2022]:

  • Daily supplementation with 200 mcg selenium slowed the loss of CD4 cells in HIV-infected patients.
  • The length of selenium supplementation and HIV infection studies varied from 9 to 24 months.
  • The selenium supplements were well tolerated in all six studies.
  • Further investigation of the effects of daily selenium supplementation of HIV-infected patients is warranted.

Note: CD4 cells are a particular type of white blood cells that help the immune system fight infections. CD4 cells are also known as CD4 lymphocytes and helper T cells [MedlinePlus 2022].

If untreated, the HIV infection will destroy many CD4 cells, and the immune system will not be able to fight off opportunistic infections [MedlinePlus 2022]. read more

Selenium and Toxic Metals and the Ageing Kidney

In individuals older than 50-60 years, the kidneys’ glomerular filtration rate decreases with increasing age. The glomerular filtration rate is a measure of how well your kidneys are working. In your kidneys, there are tiny filters (called glomeruli) that remove waste and excess fluid from the blood.

Jan Aaseth
Jan Aaseth is a Norwegian physician and professor who has done extensive research in endocrinology, toxicology, and medical biochemistry. Here we summarize his review of the relationship between selenium status, heavy metal toxicity, and the kidneys.

Exposure to toxic metals – mercury, cadmium, lead – can be detrimental to kidneys of normal adults. Accordingly, exposure to toxic metals can affect individuals with reduced glomerular filtration rates even more adversely.

Professor Jan Aaseth and a team of researchers have reviewed the available research data. Their findings show the following relationships [Aaseth 2021]:

Elderly Individuals More Susceptible to Toxic Metal Exposure

Healthy elderly individuals are capable, for the most part, of maintaining normal kidney function. However, especially after the age of 70 years, physiological changes occur in the kidneys. read more