In the past few days, I heard on the radio a comment from a prominent speaker (whose name I will not mention out of courtesy) often invited by several media to comment on the situation of the current pandemic, affirming that there was no scientific evidence indicating that Vitamin D could have a positive effect on Covid-19.

Even though his role is not a key role, according to him, everything remains to be proven. This is theoretically not wrong, if we stick to the traditional “Evidence-based medicine”.

However, I refer here to my article posted on the Vitoli blog on May 22nd, where we were dealing with prevention, and Vitamin D was the first supplement discussed. In this article, we criticized the fact that we agree to use traditional drugs to experiment against Covid-19 (e.g.: Colchicine, chloroquine, etc.), but we deny the fact that, in the same way , certain so-called “natural” supplements could also add a string to our bow.

It is therefore with some satisfaction that I learned today of an article published by Jean-François Legault of the Canadian Press, relating a particular study, the PROTEC study, directed by doctors Francine Ducharme (SHU Sainte- Justine) and Cécile Tremblay (Center hospitalier de l’Université de Montréal). These two Montreal researchers believe that the addition of Vitamin D could be significant. I’m glad to see that some serious stakeholders are ready to consider more “natural” alternatives to combat the coronavirus that we all suffer from world-wide.

Here I am quoting Dr. Ducharme: “There is a prevention effect of about 10 to 20% that has been shown already, so as to reduce the chances of a person developing a common cold. Could it work with Covid?”

The results of the study, which will include 2,414 health care workers, who are at higher risk of coming into contact with the virus, should be available within 20 weeks.

Our two Montreal researchers do not yet know what the conclusions of their study will be and they do not want people to rush the mega-doses of Vitamin D. I do not know about you, but considering the well-known Dietary Reference Intakes and the lack of sun exposure these days, I wouldn’t recommend mega-doses either, but a nice little extra of approximately 1000 IU a day wouldn’t hurt in the next few weeks.

Also note that a meta-analysis of 11,321 people participating in 25 clinical studies found a significant effect of Vitamin D in reducing the risk of respiratory infections. Likewise, a retrospective study over a 15-year period concluded that people with Vitamin D deficiency have a significantly higher risk of dying from lung disease. It is interesting to emphasize that in addition to these benefits on the risks of infection or death from pulmonary diseases, Vitamin D has an important role to play in the control of inflammatory reactions (involved in severe cases of Covid -19).

If these serious researchers have decided to dig deeper into the question, it is because it deserves our attention…!

We will be awaiting their conclusions in the coming months…

André Perreault, Pharmacist


Other suggested readings:




  • Brenner H, Holleczek B, Schöttker B. Vitamin D insufficiency and deficiency and mortality from respiratory diseases in a cohort of older adults: potential for limiting the death toll during and beyond the COVID-19 pandemic? Nutrients. 2020;12(8):2488.
  • Grant WB, Lahore H, McDonnell SL, et al. 2020. Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths. Nutrients. 2020;12(4):E988. Published 2020 Apr 2.
  • Martineau AR, Jolliffe DA, Hooper RL, Greenberg L, Aloia JF, Bergman P, et al. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. 2017;356:i6583.