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Comment by nradov | Hacker News Reader

Lack of sun exposure can cause hypovitaminosis D, which is a known risk factor for COVID-19 and other infectious diseases. It also impacts nitric oxide production which is a factor in cardiovascular system health. Supplements can mitigate the problems to an extent but are inferior to natural sun exposure.

And before anyone brings up skin cancer, there is no reliable evidence that brief daily sun exposure increases all cause mortality.

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> Supplements can mitigate the problems to an extent but are inferior to natural sun exposure.

I've never heard of such a claim, and that seems unintuitive. Why would that be? Do you have a source you could direct me to to learn more about this?

I have heard that sunlight also causes the skin to produce nitric oxide, which supposedly has all kinds of benefits.

I am not claiming this and don't have a reliable source to point to.

My understanding is that it’s extremely hard to get large scale controlled studies on sun exposure vs vitimin d supplementation, so there is lots of uncertainty still on relative efficacy. I wouldn’t say certainly that it’s inferior to sun exposure, but sun exposure can clearly have many more effects than just stimulating production of vitimin d that could then appear to correlate with D serum levels.

Some more reading specifically on vitimin D:

https://ods.od.nih.gov/factsheets/VitaminD-health%20Professi...

Can't find it now, but this is probably based on a study/studies that I've seen that showed that lack of vitamin D is correlated with bad things, but supplementation doesn't fix the bad things nearly as much as you would expect. So, the idea some people have is that vitamin D is merely a correlate of something else that sun exposure does. I call it "sun magic" :)

...sometimes I secretly wonder if sunscreen (over-)use in America would one day be found to be the cause of rise in depression and other things like that over the last few decades, kinda like lead pipes of old. I don't think it's likely but it would be kinda funny.

> Supplements can mitigate the problems to an extent but are inferior to natural sun exposure.

Inferior how?

Supplements for fat soluble nutrients like vitamin D generally have poor bioavailability unless used with specialized emulsifiers for insoluble compounds that aren't widely used [1]. The body has a hard time buffering and storing the excess, which it can't filter out through the kidneys.

It's like fast acting insulin versus insulin produced by a functioning pancreas - it's going to keep someone alive but it's not ideal for the body long term.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6631968/

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