Coronavirus and Vitamin D: Correlation, Causation, and Confusion
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The “lifestyle vitamin” has burned us before. Is Vitamin D supplementation smart in COVID-19?
I have a bit of a love-hate relationship with Vitamin D.
A brief search of my blog has shown me questioning the link between Vitamin D and multiple sclerosis, kidney disease, schizophrenia, falls, and childhood educational attainment.
So it’s no surprise, in the COVID-era, that Vitamin D comes up again. I was intrigued when Dr. Anthony Fauci, a sober and responsible voice if ever there was one during this pandemic reported his personal use of Vitamin D. Vitamin D was also part of the presidential cocktail that Trump received during his stay at Walter Reed.
I decided to dig into the data here, but before we do I want to tell you why I am inherently skeptical of Vitamin D studies. Two main issues:
1) Low vitamin D levels have been linked to so many things. Like, Vitamin C deficiency gets scurvy — fine, but low Vitamin D has been linked to everything from Alzheimer’s to Whooping Cough. It’s either the most important Vitamin in the world, or it’s a stand-in for some other important thing.
The second reason I’m a bit of a vitamin D skeptic is because when we’ve tested all these intriguing links via randomized trials, giving some people Vitamin D and some placebo, they almost always show no effect.
I feel a bit like Charlie Brown with the football here. Vitamin D has burned us before. A couple of examples.
Multiple observational studies found that people with low levels of Vitamin D were more likely to develop cancer and cardiovascular disease. These were good studies, adjusting for appropriate confounders, the whole deal.
Then we got a 26,000 patient randomized clinical trial. No effect on either outcome.
