[devaboone]

I wrote the blog post. Unfortunately I was not able to include every study on Vitamin D, and had to pare it back to the largest and/or most significant studies. Most of the studies you mention are small and published in obscure journals.

As for my argument, I would never claim that Vitamin D is "a pretty useless vitamin". It is extremely useful, and is lifesaving for people with hypoparathyroidism. But that doesn't mean we should all be taking it. Note that the studies you mention are looking at treating something, not preventing something. Many of the people supplementing are doing it because they believe it will keep them healthy - and this does not appear to be the case. That is more the point of my article. The articles you cite are interesting and hopefully will produce larger trials.

[dcx]

> Many of the people supplementing are doing it because they believe it will keep them healthy - and this does not appear to be the case.

I agree with much of your thinking - just not this particular conclusion.

1. As you mention, we know that low-to-moderate levels of vitamin D supplementation is safe.

2. We also know that a solid chunk of the population does not get enough sunlight / is vitamin D insufficient.

3. There are no large-scale trials yet for some items where vitamin D is suspected to have good effects. But there are a few nevertheless, which you share within the article itself - cancer, mortality, respiratory disease particularly stand out.

4. There are also a pile of smaller but promising, statistically significant, double-blinded, randomised controlled trials in a bunch of useful areas.

5. So this seems to be a Pascal's Wager type of situation, where supplementation is all upside and no downside, as long as people don't get crazy with it.

As you say it's not a panacea, and to cite an old comment, I am aware [1] that there are other benefits you get from sunlight. But even if it doesn't do as much as people think, I don't see why it is bad advice for most people to supplement vitamin D to keep themselves healthy!

[1] https://news.ycombinator.com/item?id=19247337

[hessp]

Would love to hear your take on this study which recently came out and gained some popularity here on HN: https://www.sciencedirect.com/science/article/pii/S096007602...

Speaking solely as a layman, that study seems like it might be extremely relevant to the discussion here. But at the same time I don't have the background necessary to critique or dissect it.

HN Post on the study: https://news.ycombinator.com/item?id=24366006