Skip to main content

Selenium’s vital role in the defense against COVID-19 and other RNA viruses

Selenium’s vital role in the defense against COVID-19 and other RNA virusesOur nutritional status is of vital importance to our health and our ability to handle infections. Selenium has several functions in the immune system, including its role as an antioxidant and in counteracting unwanted inflammation. Selenium is also able to prevent virus from mutating and becoming more virulent or creating new waves of disease. A team of Chinese scientists have reviewed a number of studies of selenium and its key role in the defense against influenza, HIV, and other types of RNA virus. They have found, among other things, that the risk of contracting a COVID-19 infection is 10 times lower in areas where the soil is rich in selenium. Therefore, it is a huge problem that selenium deficiency due to selenium-depleted farmland is so widespread in Europe, China, Africa, and many other places.

COVID-19 is an RNA virus with a unique ability to mutate. Because of that, vaccines only have limited effect and that creates new challenges. Many scientists believe that nutritional therapy can help prevent and treat COVID-19 and other virus infections. The Chinese scientists have scrutinized the massive number of published studies that already demonstrate selenium’s potential in relation to COVID-19 and other RNA viruses.

Selenium deficiency is alarmingly common

The natural selenium content in the soil in different parts of the world can vary by several hundred percent. The problem is made worse by intensive farming methods that cause even more depletion and affect the entire food chain. According to WHO reports, more than 40 countries lack selenium. The lowest levels have been registered in Europe, Africa, and a long geographical belt from the northeastern to the south-central part of China.

An estimated one billion people worldwide lack selenium

Selenium’s role in the immune defense

  • Selenium is important for a number of different selenoproteins and has the following functions in the immune system:
  • Supports the innate immune defense that fights most germs without us noticing
  • Supports the adaptive immune system that is able to specialize and produce antibodies and immunity
  • Supports the division and communication of immune cells that is vital for normal immune reactions
  • Supports antioxidants such as GPX that protect the healthy cells when the immune defense attacks
  • Counteracts unwanted inflammation
  • Prevents virus from mutating

When the immune defense attacks it produces cytokines and free radicals and initiates inflammatory processes that are meant to destroy virus-infected cells swiftly and effectively. However, it is vital for the immune defense not to overreact because that causes oxidative stress, which is an imbalance between harmful free radicals and protective antioxidants. In fact, oxidative stress is one of the main reasons why infections such as COVID-19 and other types of RNA virus suddenly become complicated and potentially life-threatening.

Overview of the relation between selenium and RNA virus

In their review article, the Chinese researchers look at different studies of selenium’s role in the prevention and treatment of various types of infection caused by RNA virus, including COVID-19.


More than 35 million people worldwide are infected with HIV (Human Immunodeficiency Virus), and there are 1.5 million AIDS-related deaths per year. In Africa and the United States, scientists have observed that the more selenium-depleted the farmland is in any given area, the greater the AIDS mortality is. Studies have shown that daily supplementation with 200 micrograms of selenium helps bolster the T cells of the immune system and may prevent HIV from developing.


Ebola is most common in Africa where the soil contains very little selenium. In the late stages of the disease, patients suffer from internal bleeding. Selenium plays a role in the coagulation process by regulating the balance between thrombin and prostacyclin and for that reason, scientist assume that severe selenium deficiency may contribute to the mortality of this disease. Studies show that selenium supplementation may lower the mortality rate. Moreover, it is possible that selenium supplements help protect the circulatory system in complicated cases of COVID-19 by way of the same mechanisms.


Keshan disease is a fatal heart disease that was originally discovered in the Keshen Province in the north-eastern part of China where the soil is extremely low in selenium. Keshan disease is caused by an otherwise harmless RNA virus called coxsackie, which the immune defense is unable to fight if the body lacks selenium. Back in 1965, the Chinese population in that area started preventing and effectively eradicating the dreaded disease by using selenium supplements.
An American study has shown that when you inoculate selenium-depleted mice with coxsackie virus, the virus has a much greater tendency to mutate in the body. The infected mice that lacked selenium developed serious lung complications, whereas mice that had plenty of selenium in their system only developed mild symptoms. The scientists behind the new article suggests that selenium may help prevent COVID-19 from mutating and becoming more dangerous.


New mutated influenza strains often originate from selenium-deficient areas and are transferred to humans from poultry or swine. Influenza is normally completely harmless but if the immune defense is weak or derailed, complicated pneumonia or life-threatening blood poisoning may occur in rare cases. Reports show that selenium deficiency increases the risk of contracting an influenza virus and it can increase the risk of lung tissue damage caused by oxidative stress. Clinical studies have already demonstrated that selenium has a positive effect on the immune response in connection with influenza.

Selenium’s role in COVID-19

A COVID-19 infection normally begins when the virus infects cells in the nose and spreads to the lower respiratory tract. Most people are able to reject the virus or may only develop a mild to moderate infection. If the immune system is not working optimally, however, the disease may turn into acute respiratory distress syndrome (ARDS), which is an acute failure of the airways. One of the main reasons for this is oxidative stress and hyperinflammation in the epithelial cells of the lungs, which may lead to circulatory failure and can cause the patient to succumb.
The immune defense depends on selenium in order to react swiftly and effectively. Selenium is also an important part of the powerful GPX antioxidants that counteract oxidative stress and protect the epithelial cells of the airways, the circulatory system, and other tissues.
In China, where the selenium levels in the soil vary greatly from one area to another, researchers have discovered that the risk of contracting a COVID-19 infection is ten times lower in selenium-rich areas.
What they have also discovered is a positive relation between selenium levels in a person’s hair and the ability to recover from a COVID-19 infection. A German study reports that patients who survive a COVID-19 infection have higher blood selenium levels compared with patients that die of their disease. And a Korean study found that COVID-19 patients who got pneumonia had severe selenium deficiency.


Selenium-depleted farmland in large parts of the world constitute a serious risk factor in connection with the spread and severity of COVID-19. Selenium is of vital importance to the immune defense and is also an essential antioxidant. Selenium’s anti-inflammatory properties help the immune defense tackle infections caused by COVID-19 and other types of RNA virus without the onset of complications. Selenium also prevents RNA virus from mutating and becoming increasingly virulent or creating new waves. One should therefore consider selenium supplementation for the many selenium-deficient population groups. It may also be a good idea to give supplements of selenium to patients affect by severe COVID-19, and the scientists behind the new study call for more research. Their review article is published in Environmental Research.

Selenium supplements

Danish agricultural crops are generally low in selenium and there is widespread selenium deficiency. Studies show that the recommended daily intake level in Denmark (55 micrograms) is not enough to properly saturate selenoprotein P, which is used as a marker for the body’s selenium status. This would require daily intake of around 100 micrograms of selenium. In most intervention studies of selenium, scientists have used 100-200 micrograms per day. It is best to take selenium yeast with a mixture of many different organic selenium types, as this is quite similar to the natural variety of selenium species that one gets by eating a balanced diet with multiple selenium sources. The European Food Safety Authority (EFSA) has established a safe upper intake level for selenium of 300 micrograms per day.

Important: Remember that vitamin D, vitamin C, and zinc are also important in the battle against virus infections

As mentioned in other articles on this web site, it is hardly a coincidence that virus infections typically circulate during the winter period. This is the time of year where vitamin D deficiency is widespread. We also need vitamin C and zinc that boost the immune defense and counteract oxidative stress.


Qiyuan Liu et al. Selenium (Se) plays a key role in the biological effects of some viruses: Implications for COVID-19. Environmental Research. 2021

Olivia M. Guillan et al. Selenium, Selenoproteins and Viral Infection. Nutrients 2019

Jones GD et al. Selenium deficiency risk predicted to increase under future climate change.
Proceedings of the National Academy of Sciences 2017

Lutz Shomburg. Dietary Selenium and Human Health. Nutrients 2017

Hoffmann Peter R et al. The influence of selenium on immune responses. Mol Nutr Food Res.

Arthur John R et al. Selenium in the Immune System. The Journal of Nutrition. 2003.

Beck MA, Levander OA. Host nutritional status and its effect on a viral pathogen. J Infect Dis. 2000.

Cowgill U.M. The distribution of selenium and mortality owing to acquired immune deficiency syndrome in the continental Unites States. Biol Trace Elem 1997.

  • Created on .