There is some reason to think this, for Covid-19. See https://www.lesswrong.com/posts/fTc3ppCW5Pq65DW8Q/chris-masterjohn-on-coronavirus-part-2#Limit_with_caveats__Vitamin_D. (The recommendation there is in fact to supplement 1000 IU daily, but it's a balance-of-probabilities thing. We have some reason to think that would be bad and some reason to think it would be good.)

[-]William Walker5y20

Look up how much vitamin D you get from an hour of full-body sun exposure... if Vitamin D weakened defense against SARS-CoV-2 (instead of helping, as it does against other viruses), the Australians and Indians would have trouble ;)

...when actually they're doing much better than the US.

[-]philh5y30

You're asking me to do a significant amount of work here, and it's not clear you understand the actual claims being made. "Vitamin D weakens defenses against SARS-CoV-2" is not a good summary of them.

Edit: oh, to be fair that was somewhat my fault, apologies. I linked to the old version, and to a part of the page below where it says it's the old version. http://reasonableapproximation.net/2020/04/28/chris-masterjohn-on-coronavirus-part-2.html has more.

[-]William Walker5y10

Thanks for clearing that up for me, I've read LessWrong for years but haven't tried to post much before the virus gave me some free time, I'm still getting used to the format.

[-]William Walker5y10

Is anyone using the short school day /two classes method? Given how the Finnish system works, it sounds promising.

Re susceptibility to SARS-CoV-2, I think this paper has a lot of the answer, especially for older people:

https://www.biorxiv.org/content/10.1101/2020.04.17.047480v2

[-]ErickBall5y50

I would like to call attention to the conflict of interest statement at the end, where the senior author Charles Brenner is identified as chief scientific adviser of ChromaDex, maker of Tru Niagen, a profitable nicotinamide riboside supplement. I'm not saying the theory is necessarily wrong--NAD+ is implicated in many aspects of aging, and aging is obviously a risk factor for Covid mortality. But the effects of NR supplementation in humans have been a bit over-hyped in the past. Again, I don't mean to imply that it does nothing, but it has been pushed as an anti-aging supplement without good evidence for improvement of biomarkers other than NAD+. For instance this study found no effect on insulin sensitivity or other metabolic measures.

[-]William Walker5y80

Sure, that's why he disclosed. (Although you're incorrect about "profitable", so far ;)

But the Sinclair lab at Harvard hates Brenner, Iowa, and apple pie, yet came to similar conclusions:

https://www.preprints.org/manuscript/202004.0548/v1

As far as lung health goes, tuberculosis prevalence is inversely correlated with B3 (of any kind, not just NR). This isn't some $@#! malaria drug or Ebola has-been, there's no side-effect downside.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3825668/