Can vitamin D help us fight the coronavirus epidemic? In March, Dr Emmanuelle Faucon from Toulon spoke for the first time about the importance of this vitamin against Covid-19. Jean-Marc Sabatier (research director at the CNRS in Marseille) and Cédric Annweiler (head of the geriatrics department at the University Hospital of Angers) then looked into the question.
Since then, they already have a ten articles published to their credit, but their conclusions are only beginning to resonate. Is vitamin D a serious avenue in the fight against the pandemic?
• What is vitamin D?
Vitamin D, whose chemical name is calciferol, is a fat soluble pro-hormone. It facilitates the absorption of calcium and phosphorus by the intestines and kidneys and helps fight against the risk of osteoporosis. Vitamin D also improves muscle strength and strengthens the immune system.
• Where can we find it?
Vitamin D exists in two main forms: D2 and D3. It is present in several foods of animal origin (D3) such as cod liver oil and fatty fish (salmon, tuna, herring, anchovies, halibut, sardines, mackerel). It is found in butter, margarine, eggs, calf’s liver. It is also produced by plants (D2) (some mushrooms), but at a lower dose.
Exposure to the sun, UVB radiation, is a source of vitamin D3. The vitamin is then synthesized by the skin.
#Confinement – Vitamin D plays an essential role in health and in strengthening our immune system.
L’@Anses_fr recalls the importance of ensuring a sufficient supply during confinement but also throughout the year.➡ https://t.co/oudXm6MZuU pic.twitter.com/XJjHVa3byQ
– Anses (@Anses_fr) April 17, 2020
In 2018, the French Food Safety Agency (ANSES) recommended a daily intake of 15 µg / d for adult men and women.
Very often, and especially in non-summer period, food is not enough. Food supplements in vitamin D (vitamin D3, cholecalciferol) compensate for any deficiencies.
• How could it be useful against Covid-19?
Jean-Marc Sabatier, research director at the CNRS in Marseille and doctor in biochemistry, believes that a sufficient level of vitamin D could reduce the probability of going towards severe forms of Covid-19. In March, when Doctor Faucon raised the importance of this vitamin, he made the connection with the mode of action of Covid-19 (SARS-CoV-2) which attacks a very important system in our body: the renin-angiotensin system.
In June, Jean-Marc Sabatier publishes two articles on the renin-angiotensin system with Cédric Annweiler and Emmanuelle Faucon as co-signatories, but also the two directors of the Wuhan virology laboratory.
When a person is infected, the virus attaches itself to a receptor called ACEII. The role of this receptor is to degrade a peptide, angiotensin 2. However, when the virus is there, degradation is hampered and there is too much angiotensin. The renin-angiotensin system then races, “what is responsible for all Covid 19 pathologies“: problems with the lungs, heart, testicles, vascular problems, dermatological disorders …
This is where vitamin D plays a fundamental role, according to the researcher. As a negative regulator, “it puts the brakes on the renin-angiotensin system when it gets carried away with the virus”, explains Jean-Marc Sabatier. She “serves as a regulator” and “counteracts the deleterious effect of the virus”.
If the infected individual is deficient in vitamin D, “like the majority of people”, the virus will further accentuate this deficiency and the person can progress to severe forms of Covid 19. Indeed, the renin-angiotensin system (which races with the virus) is “the n ° 1 system for the functioning of the body, it controls everything”, assure Jean-Marc Sabatier.
According to the French Academy of Medicine, 41% of the French population lacks vitamin D in winter. So it would be “Very important” for everyone to take a vitamin D supplement: “3,000 to 4,000 IU per day”, assures the scientific editor-in-chief of the journal Coronaviruses.
• Does it have other virtues?
In a second article, the two French scientists highlighted the importance of vitamin D in the immune system and in particular for so-called “innate” immunity, the first barrier to infection.
If the vitamin D level is too low, innate immunity may not work properly. Vitamin D is sort of “fuel” of our innate immunity. And as a result, the so-called “adaptive” immunity (found in vaccines), which is driven by innate immunity and which will fight against the pathogen, is affected.
Also, when the immune system is damaged, the cells of this system are no longer able to recognize proteins of the self and the non-self, which triggers autoimmune diseases. Vitamin D may help prevent this by helping the immune system to function properly.
• How did the researchers obtain these results?
The two French researchers produced an observational study “fortuitous”, “quasi-experimental” in an Ehpad in the Rhône just before it was affected by a significant Covid-19 infection. “It is a combination of circumstances that at the time of infection, some people had taken vitamin D shortly before”, explains Jean-Marc Sabatier.
Researchers noted that people who had recently taken a vitamin D supplement were less likely to contract a severe form of Covid 19. This study appeared in November 2020 in The Journal of Steroid Biochemistry and Molecular Biology.
Another study was previously carried out by Cédric Annweiler, head of the geriatrics department of the University Hospital of Angers, on the observation of 77 patients positive for Covid-19. In his findings, he notes that the survival rate is better for people who have received vitamin D for the long term. His study titled “Geria-Covid” was published in the scientific journal Nutrients Monday, November 2. However, with such a limited sample, it is difficult to be able to be totally categorical.
• Are other studies going in the same direction?
Several studies have recently looked into the subject. Researchers at the University of Medicine of Chicago published their work in September in the Jama Network Open medical journal. They conclude that the risk of contracting Covid-19 was almost twice as high for people with vitamin D deficiency than for those with sufficient levels.
In Norway, researchers have launched a clinical study to determine whether cod liver oil, rich in vitamin D, could have beneficial effects on Covid-19, details The world. A decision taken following a major investigation launched in March at the Oslo hospital during which 150,000 people including 2,000 positive for the virus responded to a questionnaire. Their responses show that regular consumers of cod liver oil are significantly less contaminated, and become less seriously ill if infected.
A study has also just been launched for six months in England: 5,000 people will receive treatment by post during the winter to then analyze their resistance to the virus.
In France, the clinical trial named “Covid-Trial”, underway since April is also looking into the issue. It must take into account 260 patients affected by Covid-19, over the age of 65 (150 have been included to date), recalls West France. “The aim is to find out on the fourteen-day scale the effects of a high dose of vitamin D compared to a standard dose on the survival of patients”, explains Professor Cédric Annweiler, who coordinates this new study in which nine other hospitals in France participate.
In the meantime, in an article published on October 2, WHO does not recommend the use of vitamin D as a treatment for Covid-19. “There is not enough data, she argues. Further research is needed to determine the role, if any, that vitamin D deficiency could play in the prevention and treatment of Covid-19 “.
• What is France’s position?
If Jean-Marc Sabatier claims to have written to the government several times to transmit the results of his study, the latter has not yet taken a position. However, the French National Academy of Medicine has confirmed the link between vitamin D and Covid-19 in a May 22 post. “Vitamin D cannot be considered as a preventive or curative treatment for infection due to SARS-CoV-2; but by mitigating the inflammatory storm and its consequences, it could be considered as an adjunct to any form of therapy.“. The institution recommends taking vitamin D in people with Covid-19. “It doesn’t mean that if you take vitamin D, you don’t get the virus., would like to emphasize Jean-Marc Sabatier. But we avoid going into serious forms. “
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