Scholarly Heat and Light and Vitamin D in the Pandemic

We are reading a ferocious wave of scholarly debate about Vitamin D. Though it’s over a century old, scientists still find plenty of room for debate. Especially now, in the midst of the COVID-19 pandemic, vitamin D is a hot topic.

And yet, despite all this debate, the bottom line seems relatively straightforward. If your vitamin D blood levels are too low, take a supplement.

Beyond that rather simple guidance, everything else gets a little messy.

If You Need It

It’s clear enough that taking vitamin D is a good idea if someone is deficient. In current news about the pandemic, we often hear of disagreement between the American president and top scientists. In the scant information about the president, one thing we learned was that he is taking vitamin D.

Consistent with that, Anthony Fauci recently told us on Instagram Live:

“If you are deficient in vitamin D, that does have an impact on your susceptibility to infection. So I would not mind recommending, and I do it myself taking, vitamin D supplements.”

Even so, plenty of room for controversy remains. Professor Clifford Rosen of Tufts calls the current state of evidence “a maze” and says the effectiveness of supplementation is open to question. On top of that, we have to bear in mind that too much vitamin D can indeed be toxic.

Effect on COVID-19 Risks?

The value of vitamin D for preventing bad outcomes in the COVID-19 pandemic is an especially hot topic for debate. For example, Grant et al wrote that vitamin D supplementation could reduce the risk of flu and COVID-19 infections and deaths in a recent paper. But Kow et al responded that the basis for making that claim was “mere extrapolation of available evidence which is often conflicting.”

In a similar vein, Lansiaux et al published a paper with cautious words about a correlation between sunlight exposure (which helps your body make vitamin D) and COVID-19 mortality. They called it a hint of an effect. Even so, Naudet et al responded harshly in a letter to the editor. They point to “fatal shortcomings that invalidates the analyses and conclusions” of that paper.

An RCT Offers Better Evidence

Perhaps offering better evidence, we now have a randomized controlled trial of vitamin D in patients with COVID-19. This is a small study by Castillo et al involving 76 hospitalized patients with COVID-19. Of those patients, the researchers randomly assigned 50 to get a vitamin supplement. The remaining 26 patients got the same clinical care, but no vitamin D. In the end, patients in the vitamin D group were significantly less likely to wind up in the ICU.

Vitamin D and Obesity

In a similar fashion, a debate continues about vitamin D in people with obesity. Deficiency is more common, but scientists cannot yet agree whether this is a cause or a result of obesity. So you can expect further heated discussions on this topic.

The one thing that is clear is that vitamin D deserves our attention, especially during this pandemic. If you have any doubt about whether you’re getting enough, talk it over with your healthcare provider. It’s worth making sure that you’re getting enough, without going into the harmful range of too much.

Click here for the RCT by Castillo et al and here for another recent study of vitamin D sufficiency and COVID-19 outcomes. Finally click here for further perspective on vitamin D supplementation for consumers.

Morning Sunshine, painting by Karoly Ferenczy / WikiArt

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October 6, 2020