Vitamin D is pretty contentious. If you’ve ever written about the glorious sun vitamin before, you’ll know that people are strangely passionate about it to an extent that you’ll rarely see in any arena other than sports. It’s been proposed as a cure for everything from heart disease to cancer, and we’ve run more studies on D than almost any other supplement you’d find in the second most expensive aisle of a supermarket.
People have been claiming that vitamin D is an effective treatment for Covid throughout the pandemic, based on a succession of poor-quality, biased, and sometimes even fraudulent research papers. Unfortunately, the best-quality evidence has generally not found large benefits for supplementing vitamin D, although there aren’t many good trials so it’s hard to say either way if it works.
Recently, however, the idea that vitamin D could reduce your risk of Covid-19 death to 0% has been going viral online, which is quite odd to see. Rigorous randomized trials have thus far largely failed to find a mortality benefit for the vitamin, so how could it reduce your risk to absolutely nothing?
The answer is, it turns out, that this is almost certainly not true. Take vitamin D if you want, but it’s not going to eliminate the risk of Covid-19 entirely.
The study in question is a review paper looking at observational research of vitamin D and mortality, and has recently been published in the journal Nutrients. The authors collated the results from seven papers looking at hospitals, and one ecological paper that looked at population-level vitamin D , and used these to examine the correlation between the vitamin and Covid-19 death. In particular, they plotted all…