That's interesting. People were taking supplements for this last year, until studies came out saying it doesn't make an impact. Now it looks like another reversal.
If they are truly eating well, then the vitamins should be unnecessary. It does seem that many people have a deficiency in specific vitamins, such as D. So it seems they at least need supplements if they aren't getting enough from other sources.
For example, self produced vitamin D is best because it can be more easily used and also raises serum levels for longer than than dietary or supplement sources.
Vitamin D deficiency is generally less a dietary thing and more related to UV exposure. In large parts of the world, most people don't get all that much UV exposure, particularly during the winter. So the relevant lifestyle change if you live somewhere like northern Europe or Canada would be moving to Spain, not changing diet. Most people will find taking a supplement less hassle.
Full title: COVID-19 mortality risk correlates inversely with vitamin D3 status, and a mortality rate close to zero could theoretically be achieved at 50 ng/ml 25(OH)D3: Results of a systematic review and meta-analysis (Borsche, L., Glauner, B., von Mendel, J.).
> Research shows that blood calcidiol (25(OH)D3) levels correlate strongly with SARS-CoV-2 infection severity [...] There is open discussion regarding whether low D3 is caused by the infection or if deficiency negatively affects immune defense [...] The two datasets provide strong evidence that low D3 is a predictor rather than a side effect of the infection
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As a parallel poster notes, there had been diverging results from different studies. It would be interesting, not only useful, to clarify the reasons of the divergence.
