An increasing amount of research suggests that having adequate levels of vitamin D may make the difference between having a mild vs severe case of the coronavirus.

Here’s why this research, and the recommendations coming from it, are worth paying attention to.

First, let’s recall that research conducted in 2016 indicated that vitamin D may be useful in preventing acute respiratory tract infections. Among the researchers’ conclusions: “Vitamin D supplementation was safe and it protected against acute respiratory tract infection overall.”

“a growing body of evidence”

In June 2020, Agence France-Presse reported on a “growing body of evidence which suggests that a vitamin D deficiency could be linked with developing a more severe case of COVID-19.”

The article cited a medical research study published in the British Medical Journal. The study that spanned 117 countries.

Among the study’s conclusions: “Evidence linking vitamin D deficiency with COVID-19 severity is circumstantial but growing… We … urge that vitamin D supplementation … be taken by all those at risk of deficiency, including people with darker skin or living in institutions.”

“denies the virus easy footholds”

A May 2020 study in the British Medical Journal found that “It is conceivable that vitamin D adequacy denies the virus easy footholds and thereby slows spreading of the contagion.”

That study explored factors that may contribute to vitamin D deficiency, including “old age, obesity, dark skin tone and common genetic variants that impede vitamin D status.”

A friend alerted me to this SSRN April 2020 study that found:

  • Of mild COVID-19 cases, 96% had normal levels of vitamin D
  • Of critical COVID-19 cases, 96% had insufficient/deficient vitamin D levels
  • Of severe COVID-19 cases, 96% had insufficient/deficient vitamin D levels

We’re at a frontier

Of course, correlation is not causation. And COVID-19 is a new disease; we’re at a frontier of understanding, pushing our way forward month by month. So we can’t expect perfect answers at this juncture.

That’s exactly why we need to pay attention to the medical research that we do have.

A bet with no downside

A bottle of vitamin D3 is an awfully cheap bet on nascent research. And it’s a bet that only has upside. As long as you don’t take too much of it, research shows that it can benefit your health in myriad ways.

For me, it’s been part of my daily regimen for years. (I take it with vitamin K2.)

I view D3 as part of my COVID-19 “risk management strategy” along with wearing a mask, careful hand-washing, getting sunshine and fresh air, and maintaining good air ventilation at home.

What’s your strategy?


Vitamin D and Respiratory Health
National Institutes of Health
“…[T]here is mounting evidence that [vitamin D] plays a beneficial role in the prevention and/or treatment of a wide range of diseases. In this brief review the known effects of vitamin D on immune function are described in relation to respiratory health. Vitamin D appears capable of inhibiting pulmonary inflammatory responses while enhancing innate defense mechanisms against respiratory pathogens.”

Vitamin D deficiency: a worldwide problem with health consequences
National Institutes of Health
“Vitamin D deficiency is now recognized as a pandemic… Vitamin D deficiency has been associated with increased risk of . . infectious diseases.”