Selenium Deficiency and Immune Function

Less systemic inflammation. Better immune function. Selenium is an essential trace element. Our cells cannot synthesize it. We must get it as a part of our diets. Adequate intakes are necessary for optimal immune system function.

Man in wheelchair at the beach
Autoimmune diseases develop when our own immune system malfunctions and attacks our cells. Then we suffer from autoimmune thyroid disorders, lupus, multiple sclerosis, psoriasis, rheumatoid arthritis or a hundred other autoimmune diseases.

Unfortunately, many of us live in regions with selenium-poor soil and selenium-poor crops and fruits. We do not get sufficient selenium from our food [Stoffaneller & Morse 2015]. Adequate selenium intake and status are vital. There are increased health risks associated with selenium deficiency.

What Defines Selenium Deficiency?

Data from the BIOSTAT-CHF observational cohort study indicate that serum selenium concentrations under 70 mcg/L constitute a deficiency status. Serum selenium concentrations under 100 mcg/L constitute a sub-optimal status [Bomer 2020]. read more

Selenium and Hypothyroidism

In the CATALYST study, researchers found that selenium supplements and placebo supplements improved the quality of life of patients with hypothyroidism to an equal extent. Accordingly, the researchers have now emphasized a need for more research into the effect of selenium supplementation on immune system function, on oxidative stress, and on low-grade inflammation in patients with thyroid diseases [Larsen 2024].

Thyroid system depicted
Depiction of the thyroid system. Attribution: Attribution: Mikael Häggström, Public domain, via Wikimedia Commons. The CATALYST study (Chronic Autoimmune Thyroiditis Quality of Life Selenium Trial) sought to establish whether selenium supplementation improves quality-of-life in patients with autoimmune thyroiditis .

The CATALYST study was a multi-center randomized, double-blinded, placebo-controlled clinical trial conducted in Denmark. The study participants were patients aged 18 or more years with serum thyroid peroxidase antibody (TPOAb) levels equal to or greater than 100 IU/mL. 82% of the study participants were women [Larsen 2024]. read more

Selenium and a Longer Healthier Life

The micronutrient selenium has antioxidant and anti-aging properties. Specifically, numerous selenoproteins, in which selenium is an essential component, have antioxidant, anti-inflammatory, and immunostimulating effects [Bjørklund 2022].

Why is this important?

Old people
Biological aging involves the gradual worsening of the composition of our cells and organelles. It involves the slowing down of our body functions. Aging is typically accompanied by wrinkled skin and thinner skin, by a loss of body mass and bone density, and by poorer eyesight. The older we get, the more vulnerable we are to loss of cognitive function and dementia, heart trouble, osteoporosis, renal failure, viral infections, etc. Eventually death comes.

The aging process is characterized by the following inevitable physiological developments [Alehagen 2021]:

Selenium and selenoproteins and antioxidant protection

One theory of biological aging is that oxidative stress and chronic low-grade inflammation play an important role in aging-related physical and mental decline. Harmful reactive oxygen species – popularly known as free radicals – overwhelm the ability of the available antioxidants to neutralize them. The harmful free radicals cause oxidative damage to the cells and to the DNA, lipids, and proteins in the cells [Bjørklund 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

Selenium and Viruses and Viral Infections

Viruses are very tiny germs that consist of genetic material (DNA or RNA) inside a protein coating. Unlike bacteria, viruses cannot survive on their own. They need host cells [MedlinePlus 2016].

Sneezing
When viruses invade the body, they hijack human cells and use the cells to reproduce themselves. The host immune system attempts to fight off the invasive viruses. If the immune system defense is not successful, then various viruses cause such infections as the common cold, influenza, and warts. Other viruses cause severe illnesses such as COVID-19, Ebola, and HIV/AIDS [MedlinePlus 2016].
Antibiotics are not effective against viruses. For some few viral infections, there are effective antiviral medicines. For others, vaccines may be an option. In any case, it is important to have a strong immune system to ward off or recover from viral infections.

Harmful free radicals play an important role in viral infections. The cells’ normal metabolism of oxygen generates reactive oxygen species as a by-product. At low and stable levels, these “free radicals” play a role in cell signaling and cell functioning. In the course of viral infections, however, the over-production of free radicals can overwhelm the body’s protective antioxidant systems and can cause oxidative stress [Guillen 2019]. read more

Selenium and Immune Function and DNA Repair

Selenium is a trace element essential for for DNA repair, for  good immune function, and for reduced mortality risk.

DNA double helix
Cell studies, animal models, and human clinical trials suggest that an optimal supply of selenium is required to enhance the process of DNA damage repair.

The Micronutrient Information Center maintained by staff members at the Linus Pauling Institute of the Oregon State University provides reliable information about the vitamins and minerals and trace elements used in nutritional supplements.

Today, I want to summarize the information that the Center provides about selenium and supplement that information with the latest scientific research.

An Introduction to Selenium and Selenoproteins

Selenium is a trace element that is essential that humans need for the proper functioning of selenium-dependent selenoproteins. Free selenium is rare in the body. Instead, the selenium in the body is typically a component of selenomethionine, selenocysteine, and methyl-selenocysteine. read more

Selenium Supplementation Strengthens Immune Response to Covid-19

The available vaccines do not seem up to the task of preventing infection by the fourth wave of the Covid-19 virus. Accordingly, people in high-risk groups may want to start on a course of supplementation to address possible deficiencies of selenium, zinc, and vitamin D to strengthen their immune response [Alexander 2020].

Covid-19 vaccine
Resistance to Covid-19 and other viral infections, strengthening of immune system function, and reducing chronic inflammation all depend on adequate intakes of zinc, selenium, and vitamin D [Alexander 2020].
In this article, we will address the importance of adequate selenium intakes. Readers are encouraged to google zinc and Covid-19 and vitamin D and Covid-19 on their own.

Early initiation of adequate selenium, zinc, and vitamin D supplementation in high-risk individuals and in high-risk areas and, certainly, as soon as possible after the time of suspected infection with the Covid-19 virus can help the immune system [Alexander 2020]. read more