The mortality associated with Covid-19 varies from population to population. To date, the reasons for these differences in death rates are still not well understood. But scientists suspect that a vitamin D deficiency may be responsible.
Less than a month ago, many health agencies worldwide reminded us of the importance of ensuring an adequate intake of vitamin D for a strong immune system. This is all the more important at this time of the coronavirus crisis. A recommendation that seems even more relevant today as a study by scientists at Northwestern University showed that patients with vitamin D deficiency are twice as likely to develop a severe form of covid-19.
To reach this conclusion, the team conducted a statistical analysis of data from hospitals and clinics in several countries, including China, Iran, the United States and France. They concluded that differences in the Covid-19 mortality rate between countries cannot be explained by the quality of health care systems, the age distribution of the population or the availability of tests. However, there was a significant correlation between mortality and vitamin D deficiency.
Lower average vitamin D levels in Spain and Italy
This conclusion seems to be confirmed by other studies carried out by scientists from the University of England Ruskin and Queen Elizabeth Hospital in the United Kingdom. This study was prompted by earlier work that reported an association between low vitamin D levels and susceptibility to acute respiratory infections. According to these researchers, Italy and Spain – whose inhabitants, especially the elderly, tend to hide from the sun – have lower average vitamin D levels than most northern European countries, which consume more cod liver oil and absorb more sunlight. The mortality rate of Covid-19 is higher in Italy and Spain than in the Scandinavian countries.
Vitamin D is found in many fatty foods. These include sardine fish, salmon and mackerel, offal, egg yolk, butter and cheese.
Our body can also synthesize vitamin D when exposed to the sun. It is therefore recommended to expose hands, forearms and face to the sun for 15 to 20 minutes daily in spring.
vitamin D deficiency
“This does not mean that we should all take vitamin D supplements,” says researcher Vadim Backman of Northwestern University. But these data could shed light on the mechanism of covid-19-related mortality and perhaps lead to new therapeutic targets.
In particular, scientists have observed a strong correlation between vitamin D levels and the dreaded “cytokine storm” a hyperinflammatory condition caused by an overreaction of the immune system observed in patients with severe forms of Covid-19. And which seems to be the cause of death in most of them. So, according to scientists from Northwestern University, vitamin D prevents dangerous overactivity of our immune system. By modulating the white blood cell response and preventing the release of too many inflammatory cytokines.
Taking too much vitamin D can also lead to adverse effects
The “correct” level of vitamin D will not prevent Covid-19, but it can protect against serious complications. However scientists still warn that taking too much vitamin D can lead to undesirable side effects. They consider that the effect of vitamin D should be further investigated in the specific case of Covid-19, in particular to determine the right dosages. However, it is certain that people who are deficient in vitamin D should consult their doctors to remedy the situation.