Vitamin D on Blue

Flooding the Zone with Vitamin D Studies

Let’s call it a flood – an overwhelming flood of information and misinformation about Vitamin D and COVID-19. But the volume is so great that distinguishing truth from fiction can be difficult. Furthermore, our knowledge is incomplete. So we have lots of speculation and relatively fewer solid facts. Meanwhile, researchers continue flooding the zone with vitamin D studies.

In mid November, one of the largest studies yet found no benefit from a high single dose of vitamin D for hospitalized COVID-19 patients. However, this study has not yet gone through peer review. To further muddy the picture, another study of high dose vitamin D came out just a few days beforehand. It was much smaller, but its results suggested that vitamin D could help mildly affected patients clear the virus more quickly. What’s more, this study is published and peer-reviewed.

Different Studies, Different Results

These are both randomized, controlled studies of high-dose vitamin D, given orally to patients with COVID-19. But the similarities end there. These are studies of two very different patient populations, given different doses, with different goals.

The larger study enrolled 240 patients hospitalized with severe COVID-19. The randomization assigned them to get either a single oral dose of Vitamin D3 – 200,000 units or a placebo. The goal was to shorten their hospital stay. Igor Murai was lead author of this study and wrote a rather blunt conclusion:

“Vitamin D3 supplementation does not confer therapeutic benefits among hospitalized patients with severe COVID-19.”

Of course, because this study is a pre-print, we take it with a grain of salt. Many studies on vitamin D have recently come into question, which makes us even more cautious.

A Smaller Study with Patients Less Ill

The smaller study enrolled only 40 patients. But these patients were not as sick – they had mild or no symptoms. So the goal was different. It was to help patients clear the virus from their bodies and get to a negative viral RNA test result. The dosing was similar but not the same. These patients either got a placebo or 60,000 units of vitamin D daily for seven days. Within 21 days, 63 percent of patients receiving vitamin D tested negative for the virus. Only 21 percent of people in the placebo group did.

The authors, led by Ashu Rastogi, write that these are encouraging results:

“A reassurance for public health workers regarding greater likelihood of SARS CoV-2 RNA negativity in individuals receiving therapeutic cholecalciferol supplementation will be encouraging.”

Believing Versus Knowing

Clearly, vitamin D is relevant for good health in the midst of the COVID-19 pandemic. But our knowledge of the details is fragmentary. We have mixed information on the therapeutic benefits in symptomatic patients. The large RCT by Murai et al with a negative result gives us reason for caution.

However, evidence from the Rastogi study reminds us that vitamin D likely does have a role.

Though we tend to believe that this is true, we don’t yet know what the limits of that role might be. Thus we come back to a very basic point. The best thing we can all do is to be sure we have enough vitamin D and not too much. If you have doubts, ask you doctor and find out what your blood levels are.

Click here for the Murai study and here for the Rastogi study. For further perspective, click here and here.

Vitamin D on Blue, photograph © Ted Kyle / flickr

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December 2, 2020

2 Responses to “Flooding the Zone with Vitamin D Studies”

  1. December 02, 2020 at 12:29 pm, David Brown said:

    Again, the focus is on treating symptoms rather than on preventing the cause. Metabolically healthy people, obese or slim, are resistant to COVID-19 complications. Supplements cannot protect the metabolically unhealthy from COVID-19 complications. That has to be done with ‘healthy’ changes in fat intake. For example: “Unsaturated fatty acids (UFAs) also affect obesity, and not all obesity is the same. It is the UFA component in obesity that determines the degree of harm in the event of acute lipolysis as in severe COVID-19 or acute pancreatitis. A larger proportion of UFA accumulation in adipose fat — even when the overall fat amount is lower, as in a leaner person — may be more harmful during acute lipolysis than a greater proportion of saturated fat.” In addition, “It has been known for a long time that the composition of the fat we store in adipose tissue takes several years to change in response to changes in diet…In the long term, avoiding high UFA intake may help with future pandemics like COVID-19, and severe pancreatitis or similar disease scenarios.”

  2. December 02, 2020 at 1:31 pm, Ted said:

    David, to my knowledge, there is no evidence to support a claim that unsaturated fatty acids can prevent or cause worse outcomes with COVID-19. The link you provided is speculation about the meaning of an association, but it is not evidence of causality.