Vitamin D deficiency promotes mortality

From one population to another, mortality from Covid-19 varies. Even today, the causes of these variations are not well understood. But researchers suggest that a vitamin D deficiency may be to blame.

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Less than a month ago, ANSES, theNational Agency for Food, Environmental and Occupational Health Safety reminded us of the importance of ensuring adequate vitamin D intake. Even more during this period of coronavirus crisis. Objective in particular: to avoid a weakening of our immunity. A recommendation that seems even more timely today, when Northwestern University researchers (United States) tells us that patients with vitamin D deficiency are twice as likely to develop a severe form of Covid-19 as others.

To reach this conclusion, the team performed statistical analysis of data – not yet peer-reviewed – from hospitals and clinics in several countries including China, Iran, the United States and France. According to them, the differences between Covid-19 mortality rate from one country to another cannot be explained by the quality of healthcare systems, by the age distribution in the population or by the availability of tests. However, they noted a significant correlation between death rate and vitamin D deficiency.

A conclusion that already seems to confirm another study, carried out by Anglia Ruskin University and Queen Elizabeth Hospital researchers the UK. A study motivated by previous work which signaled an association between low vitamin D levels and sensitivity to acute respiratory tract infections. According to these researchers, Italy and Spain – whose inhabitants, especially the older ones, tend to hide from the Sun – have lower average vitamin D levels than most northern European countries – who consume more cod liver oil and take more the Sun. However, the mortality rates linked to Covid-19 in Italy and Spain are higher than in the Scandinavian countries.

Tracking Vitamin D Deficiencies

“It doesn’t mean that we should all take vitamin D supplements, says Vadim Backman, a researcher at Northwestern University in the communicated. But these data could shed light on the mechanism of mortality linked to Covid-19 and why not, lead to new ones. therapeutic targets “

The researchers observed in particular a strong correlation between the levels of vitamin D and the famous ” cytokine storm“. This hyper inflammatory condition caused by an overactive immune system seen in patients with severe forms of Covid-19. And that seems to be the cause of the deaths of the majority of them. So, according to researchers at Northwestern University, vitamin D prevents our immune system to become dangerously hyperactive. By modulating the response of white blood cells, preventing them from releasing too many inflammatory cytokines.

Levels “Correct” vitamin D would not prevent catching Covid-19. However, they could protect against the serious complications associated with it. But researchers still warn against taking too much vitamin D, which could have unwanted side effects. They recognize that the question of the mode of action of vitamin D in the specific case of Covid-19 must be investigated more precisely in order in particular to be able to define a kind of “Beneficial dose”. But it is certain that more than ever, people in a situation of deficiency should consult their doctors in order to remedy it. Even if, recalls Petre Cristian, a researcher at Queen Elizabeth Hospital in thecommunicated , “Correlation does not necessarily mean causation”.