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Comment by layoutIfNeeded | Hacker News Reader

>more sun

Pls no. Skin cancer is no joke.

Sun exposure increases skin cancer risk, but skin cancer is in most cases easily treatable if caught early, and there's evidence that sun exposure reduces all cause mortality, e.g.:

http://ar.iiarjournals.org/content/38/2/1173.long

If this is a real causal link, the next important question is how much is attributable to vitamin D synthesis (which, assuming the localization of vitamin D in the skin isn't important, could theoretically be replaced by supplements), and how much is attributable to things that can't be supplemented, e.g. increased nitric oxide synthesis. See:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5593895/

Vitamin D supplements keep failing to show broad benefits in trials.

Here's a popular press writeup with citations to the relevant trials: https://www.vox.com/2018/10/4/17933880/vitamin-d-health-sun-...

I live far enough from the equator, and get little enough sunlight exposure, that I believe I was deficient. After I started supplementing I noticed my fingernails growing stronger. I didn't anticipate this happening so I didn't save samples for objective measurement, but I clearly remember that my fingernails would easily buckle if I pressed the ends against each other, and now they do not. The cost and risk is very low, so I think it's worth it for the stronger fingernails (useful as prying tools).

The elephant in the room is that big confounding factors can be expected: healthy people get more sunlight; also, people who go outside more during the daytime are likely to have healthier social lives, which is big for CVD. So the question is, how much, if any, does the sunlight itself benefit health, given that we could expect a strong correlation even if the answer is "negatively"?

What I mean is 20 minutes/day to get your Vitamin D levels right.

https://www.outsideonline.com/2380751/sunscreen-sun-exposure...

Nor are these damn rickets.

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