We all know that vitamin D can help support your immune system, but do you know how important selenium is in helping to fight viral infections?
A few months ago our Senior Nutritionist, Frankie Brogan, addressed how vitamin D and vitamin C typically get more coverage when it comes to immune system support - even though selenium also plays a very important role.
Over the months there has been a lot of new research surfacing on just how crucial selenium can be with viral infections, particularly surrounding COVID-19. However people still don’t seem to be talking about it enough.
Selenium and Keshan disease
Selenium is an important nutrient and deficiency is common. Our article here explains the dietary reasons behind why the UK and Europe can be especially deficient in selenium.
Selenium and disease were first linked back in the 1960s with the rise of Keshan disease - a heart condition that affected regions throughout China with selenium deficient soils.
It was found that adding selenium into the soil fertiliser as well as supplementation reduced development of the disease. (1) Since then, many studies have looked at how selenium can play an important role in viral infections. (2)
Selenium and oxidative stress
One of the causes of viral invasion and uncontrolled inflammation is oxidative stress. This is caused by free radicals which damage cells, and are managed by selenium dependent proteins. Since selenium is required for the body to produce these selenoproteins, oxidative stress is especially likely to occur in those with low levels.
Selenium and COVID-19
Pharma Nord UK Medical Advisor, Dr. David Mantle, recently explored the link between virus infection and selenium among other nutrients, and the potential benefit of supplementation in COVID-19 infection.
"Some of the most compelling evidence regarding the detrimental effect of selenium deficiency and susceptibility to viral infection relates to Keshan disease, where dietary supplementation with selenium was shown to completely prevent development of this disorder.
"One area of COVID-19 research which to date has received relatively little attention is the role of nutrients in the inflammation negative feedback loop.
"There is evidence that a number of nutrients, including vitamin D3 (3), selenium (4), and beta 1,3/1,6 glucans (3) have important roles in mediating the inflammation negative feedback mechanism.
"There is also evidence that levels of these nutrients, especially vitamin D (5), may be deficient in the UK population, particularly the elderly, who may therefore be at increased risk of uncontrolled inflammation following COVID-19 infection (6).
"It therefore follows that supplementation with these nutrients may reduce the risk of tissue damage resulting from uncontrolled inflammation in patients following COVID-19 infection.
"It is also important to note that selenium reduces the formation of thrombosis in the blood vessels. Blood coagulation disorders leading to the formation of micro-clots, which are a significant cause of death in patients with COVID-19.’ (7)
More links with selenium and COVID-19 were made in a recent study posted on the The American Journal of Clinical Nutrition. Researchers collected data on COVID-19 cases in China in correlation to selenium levels. Results showed a significant association between the reported cure rates for COVID-19 and selenium status. (8)
The study also notes previous viral infections where selenium supplementation showed significant clinical benefits and that evidence proves selenium’s ability to "influence viral mutation and evolution." (9)
Additionally, another recent article published on Cambridge Core addressed the strong evidence surrounding selenium’s ability to protect against viral infection and supporting immune response. The study references severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and selenium’s role in fighting such highly inflammatory responses.
Researchers concluded that individuals with low selenium status may benefit from supplementation to prevent the development of severe forms of COVID-19. (10)
When supplementing with selenium, it’s important to make sure that the supplement preparation offers a guarantee of precise selenium dose with pharmaceutical grade organic selenium yeast for the best quality.
High intake of selenium can be potentially harmful, so it is recommended by the Department of Health that daily intake of selenium should not exceed 350mcg.
(1) An original discovery: selenium deficiency and Keshan disease (an endemic heart disease)
(2) Selenium, Selenoproteins and Viral Infection
(3) Chen Y et al (2013) 1,25-Dihydroxyvitamin D promotes negative feedback regulation of TLR signaling via targeting microRNA-155-SOCS1 in macrophages. J Immunol; 190: 3687-3695.
(4) Huang Z et al (2012) The role of selenium in inflammation and immunity: from molecular mechanisms to therapeutic opportunities . Antioxid Redox Signal; 16:705-743.
(5) Poltajainen A et al (2013) Beta-glucan inducible microRNAs negatively regulate inflammatory response. Cytokines; 63: 290.
(6) Crowe FL et al (2019) Trends in the incidence of testing for vitamin D deficiency in primary care in the UK. BMJ Open; doi: 10.1136/bmjopen-2018-028355.
(7) Fogarty H et al (2020) COVID-19 Coagulopathy in caucasian patients. Br J Haematol. doi: 10.1111/bjh.16749
(8) Association between regional selenium status and reported outcome of COVID-19 cases in China
(9) Beck MA, Handy J, Levander OA. Host nutritional status: the neglected virulence factor. Trends Microbiol. 2004;12:417–23
(10) Selenium and viral infection: are there lessons for COVID-19?