Widespread selenium deficiency increases the risk of dying of COVID-19

The trace element selenium has a vital yet overlooked role in ensuring a well-functioning immune system, and the widespread problems with selenium deficiency increase the risk of dying of COVID-19, according to a large German study that is published in the science journal Nutrients. The scientists therefore conclude that determining the patients’ blood selenium levels may provide vital diagnostic information. Also, the researchers conclude that it may be necessary to include selenium supplements in the treatment of COVID-19, especially with older people, diabetics, and those with chronic diseases that are at particular risk of life-threatening complications. The agricultural soil in Europe and other parts of the world contains relatively little selenium, which is why it is imperative to focus more on getting adequate amounts of this essential nutrient for the sake of preventing COVID-19 and other viral infections. It appears that the official recommendations – the so-called reference intake levels or RI – are not sufficient to meet the body’s actual requirements.

You get selenium from foods like fish, eggs, organ meat, wholegrains, and Brazil nuts. Still, an estimated one billion people worldwide lack selenium because of the nutrient-depleted soil. For this reason, German scientists wanted to look closer at selenium’s impact on the immune defense of people with COVID-19 to see if there is any link between selenium status and life-threatening complications.

How can COVID-19 be harmless and lethal at the same time?

When you get an infection the white blood cells of your immune system use free radicals as aggressive attack weapons or missiles. The production of pro-inflammatory cytokines also generates cascades of free radicals. What is important here is to make sure that the free radicals are harnessed in order to avoid oxidative stress, which is an imbalance between free radicals and protective antioxidants. Most people infected with COVID-19 have mild, flu-like symptoms. However, if they lack antioxidants such as selenium, they have an increased risk of oxidative stress and a derailed immune system.
When COVID-19 infections become life-threatening and the weakest patients die it is not the virus itself that is the problem. It is the fact that the immune system overreacts with a cytokine storm and hyperinflammation and attacks healthy tissues and causes acute respiratory system failure. This condition is known as acute respiratory distress syndrome – or ARDS – and may result in secondary damage to the circulatory system and other organs. The German scientists also point to the fact that the immune system launches the same uncontrolled and potentially dangerous mechanisms when conditions like SARS (severe acute respiratory syndrome), blood poisoning, and influenza become life-threatening.

Selenium’s role in the immune defense

Selenium supports more than 25 different selenium-dependent enzymes called selenoproteins, which control the energy turnover, function as antioxidants and have a variety of other essential functions. With regard to the immune defense, selenoproteins are involved in the following:

• The innate immune defense that fights most germs without us noticing
• The adaptive immune defense that is able to specialize and produce antibodies and immunity
• The immune system’s communication and cell division
• Powerful antioxidants like glutathione peroxidase (GPx) that can counteract oxidative stress and protect healthy tissue against damage

Selenium prevents virus from mutating

Infections like COVID-19, colds, influenza, and herpes are caused by different types of RNA virus that can easily mutate (alter their antigens). This means that the immune defense must start all over again with the recognition process. This is particularly problematic in situations with impaired immunity. Here, selenium plays a vital role.
Professor Melinda A. Beck has demonstrated that selenium-depleted mice infected with influenza virus A have an increased rate of RNA mutations. The selenium-deficient mice therefore have difficulty with fighting the influenza infection, unlike mice that have plenty of selenium. Also, the selenium-depleted mice developed serious lung complications as a result of the infections, whereas the mice with healthy selenium status only had mild symptoms.
Selenium is important because it prevents virus from mutating, while ensuring a swift and mild course of the infection. It is hardly a coincidence that several new virus strains – including influenza and coronavirus – originate from selenium-depleted parts of China. It is also in these regions that the virus is transmitted from animals to humans.

Lower blood selenium levels mean increased risk of dying of COVID-19

The new German study was carried out in collaboration with the Heidelberg University Hospital and other health science institutions. The scientists took blood samples from the COVID-19 patients and studied levels of selenoprotein P, which is used as a marker of the body’s selenium status. They also measured the activity of powerful antioxidants like glutathione peroxidase (GPx). The researchers could see a clear relation between lack of various selenoproteins and COVID-19 mortality. This may be a result of low selenium content in the diet combined with the fact that the immune system uses a lot of selenium to fight infections. Both things cause blood selenium levels to drop.
It also appears that older people, diabetics, and those with chronic disease already have low-grade inflammation in the body, which depletes their selenium levels. This increases the risk of cytokine storm and hyperinflammation, which makes COVID-19 life-threatening.
The scientists conclude that selenium supplements may be necessary as part of the treatment for COVID-19 to help patients recover faster. It is a safe and inexpensive treatment that is natural at the same time.
It goes without saying that selenium is also important for preventing COVID-19 and making it less likely that an infection becomes complicated.

The new study confirms earlier studies

Earlier research carried out by the British selenium researcher, Professor Margaret Rayman, reveals differing selenium content in soil in different parts of China. Her research shows that COVID-19 patients in regions with plenty of selenium have a much higher recovery rate, simply because crops in these parts of the country have a higher selenium content. Also, by measuring selenium status from hair samples taken from people in 17 cities outside of Hubei, Rayman’s research demonstrates that higher selenium status means significantly better recovery chances. In contrast, the COVID-19 mortality rate is nearly five times higher in areas with selenium-depleted soil.

Official recommendations – the reference intake levels – are not optimal

As mentioned, selenoprotein P is used as a marker of the body’s selenium status. Still, studies show that the official recommendation for selenium that suggests a daily reference intake of 50-70 micrograms is not enough to properly saturate selenoprotein P. This would require daily intake of at least 100 micrograms of selenium. In the case of an infection, the selenium requirement is bound to be even higher.
Selenium yeast with a variety of different selenium species is preferable, as this is the closest you can come to a balanced diet with multiple selenium sources. The European Food Safety Association (EFSA) has set the safe upper intake level for selenium at 300 micrograms per day.

References:

Arash Moghaddam et al. Selenium Deficiency is Associated with Mortality Risk from COVID-19. Nutrients 16 July 2020

Zhang J et al. Association between regional selenium status and reported outcome of COVID-19 cases in China. The American Journal of Clinical Nutrition. Apr. 2020

James Ives. Researchers identify link between COVID-19 cure rate and regional selenium status. News Medical Apr 29 2020

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.