Covid: Vitamin D protects from a serious form of the virus?
US researchers estimate that coronavirus patients with severe vitamin D deficiency are twice as likely to have serious complications from the infection, including death. This vitamin is really essential to regulate the response of the immune system when fighting disease.
Vitamin D plays an essential role in the absorption of certain minerals by the body. It is important to guarantee an adequate intake because this vitamin plays an essential role in particular in the quality of bone tissue (prolonged insufficiency leads to fragile bone health, increasing the risk of fracture) and muscle, as well as in strengthening the immune system. In the current context of the Covid-19 epidemic, where immune defenses can be particularly challenged, researchers at Northwestern University state in a study that there is a correlation between severe vitamin D deficiency and a higher death rate.
To arrive at this discovery, the researchers performed statistical analysis of data from hospitals and clinics in China, France, Germany, Italy, Iran, South Korea, Spain, Switzerland, the United Kingdom, and the United States. They then noted that patients in countries with high COVID-19 mortality rates, such as Italy, Spain, and the United Kingdom, had lower levels of vitamin D. But the latter warns: this does not in any way mean that we should, in particular People with no known deficiency, start taking supplements without medical advice.
A risk factor in its own right?
"Although I think it is important to know that vitamin D deficiency could play a role in mortality, we do not need to encourage everyone to take it," says Professor Vadim Backman, who led this research. "This requires further study and I hope that our work will stimulate interest in this area. The scientific team looked closely at the possible protective role of vitamin D after noting unexplained differences in Covid-19 mortality rates from one country to another. Currently, the factors often mentioned are the quality of health care systems, age, availability of tests or strains of the coronavirus.
But for these researchers, none of these factors seems to play a big role. “The health system in northern Italy (one of the countries most affected by the coronavirus) is one of the best in the world. There are differences in mortality even if we look at the same age group, and although the restrictions on the tests vary, the disparities in mortality still existed when examining countries with a similar number of tests, "adds Professor Backman. Therefore , the scientific team raises another hypothesis: a link between vitamin D levels and cytokine storm, a hyperinflammatory condition caused by an overactive immune system.
Vitamin D to prevent an exaggerated immune response?
In fact, only certain people develop a severe form of Covid-19, and this phenomenon does not appear to be directly related to the virus: it is likely due to the nature of the immune response developed by their body. We speak of "cytokine storm", a phenomenon related to the overproduction of certain mediators of inflammation (cytokines). This particular immune response can severely damage the lungs and cause acute respiratory distress syndrome and death in these patients. "This is what appears to kill most Covid-19 patients, not destruction of the lungs by the virus itself. The researchers add.
It is in this situation that vitamin D would play an important beneficial role. Vitamin D is not only essential for the immune system as a whole, but it will also prevent it from becoming dangerously overactive during infection. This means that having a good level of vitamin D in the body could protect patients from their serious complications, including death. "Our analysis shows that it could cut the death rate in half, says Professor Vadim Backman, it will not prevent a person from contracting the coronavirus, but it can reduce complications and prevent the death of infected people."
The latter clarified once again that supplementing with vitamin D alone is not recommended, which could lead to negative side effects. Furthermore, more studies are needed to discover more specifically how it can be used most effectively to prevent the occurrence of Covid-19 complications in patients. "It is difficult to say which dose is the most beneficial. However, it is clear that vitamin D deficiency is harmful. This could be a key to protecting vulnerable populations, such as the elderly, who have a known prevalence of vitamin D deficiency", concludes the scientist.