
Vitamin D deficiency worsens Respiratory Tract Infections: Meta-analysis - HaukeHi
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6747229/
======
DocG
Absolutely, not only respiratory but all the illnesses. It affects your immune
system. But with cavaets:

\- It won't make any effect for around month once you start taking it

\- it only has effect if you have serious deficiency.

I used to be sick really easily for years, always tired. Finally got doctor to
make blood tests and if normal level 100, min is 60, then my vitamin D levels
were 12. Ofcourse my body immune system struggled. After started with
suppliments got more energy, got less often sick. Felt like a normal person.

There is also other extreme, taking too many will have negative effect. I've
experienced them myself.

I do live in a northern climate (imagine Finland) with long dark winters and
only sun time is spend in the office.

~~~
macawfish
If you take a lot of vitamin D, you have to make sure that you are getting
enough magnesium.

Also, vitamin D really shouldn't be taken any other time than before noon.

(Not sharing this for you in particular, just for anyone reading who decides
to try vitamin D supplementation for the first time. Doctors aren't always
sharing she vital info about how to take vitamin D)

~~~
tudelo
> Also, vitamin D really shouldn't be taken any other time than before noon.

I'm sure I could go find sources, but it might be helpful if you link them
here. It's hard to believe comments that give medical information and
disparage doctors.

~~~
mattmanser
I'm actually just completing a high-strength vitamin D tablet course and the
advice for taking it in the instructions is to take it with your evening meal,
so sounds like a load of hogwash.

Here, for example, are the instructions that came with my tablets:

[https://www.sunvitd3.co.uk/site/wp-
content/uploads/2019/01/S...](https://www.sunvitd3.co.uk/site/wp-
content/uploads/2019/01/SunVit-combi-PIL_v24.pdf)

Note the:

"Please Note: SunVit-D3® tablets should be swallowed whole with water and
taken in the evening with a main meal."

~~~
belltaco
The reason for that recommendation is that Vitamin D absorbs better in a meal
with fat, and dinner is the biggest meal for most people.

See my other comment in reply to parent. There might be lower quality sleep
because of the timing.

[https://www.gwern.net/zeo/Vitamin-D](https://www.gwern.net/zeo/Vitamin-D)

------
damla
While one supplement is in trend, as now with vitamin D, when you search and
try to make a decision if you should supplement it, you always end up deciding
it is beneficial, or at least doesn't hurt to. But as the trend fades, you may
find that it is not that important or even harmful to overdose in specific
situations.

So I am skeptical of supplements as a rule. Of course there are a couple of
odds, like iodine, which is so beneficial to supplement in general community,
that it is added to table salt as default, you only skip if you have specific
conditions like thyroid problems.

I wish there were more research or comments on possible harms and
disadvantages of excessive use of vitamin D, than I think I could more easily
decide to use.

~~~
IkmoIkmo
I really don't see the issue. All vitamin d sales come with daily dosage
information. There's (always going to be) some issues with literacy to
understand this information, but that's it.

If you follow the daily dosage information, you won't even get near harmful
levels of vitamin d. Recommended is about 600 IU daily. If you take 60.000 on
a daily basis for months, you build up toxicity.

For that you typically need to take 30 pretty strong 2000 UI pills on a daily
basis for months, while ignoring the label that states each pill is typically
250% of the daily recommended amount, and the instruction which notes the
tolerable levels max out at just two daily pills.

Toxicity is extremely uncommon. Whereas deficiency is extremely common. Up to
a billion people are expected to have some form of vitamin d deficiency.

That's not to say it's not a problem, but rather that it's very rare, nothing
like say an opioid overdose problem. As with all things, balance is key. You
can overdose on 5 cents of water in the span of 5 minutes. Acute vitamin d
overdose is known to happen if you take something like 300-1000 pills of 2000
UI over a period of days, which is pretty insane.

~~~
jp555
You reminded me of a paper that suggested that there was an error made in
developing the RDA of Vitamin D; the 600IU RDA may be wildly wrong.

“ It also estimated that 8895 IU of vitamin D per day may be needed to
accomplish that 97.5% of individuals achieve serum 25(OH)D values of 50 nmol/L
or more.”

[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4210929/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4210929/)

------
kasperni
A similar article was discussed previously here
[https://news.ycombinator.com/item?id=22463713](https://news.ycombinator.com/item?id=22463713)

~~~
HaukeHi
This is a more recent meta-analysis, but thanks it's helpful that you're
linking to the discussion.

------
jwr
From the first sentence in the abstract:

"however, findings are inconsistent"

~~~
HaukeHi
Agreed - I believe the meta-analysis and the underlying studies are likely of
poor quality.

I think it might be worth for people here to reanalyze everything.

The effect sizes seem large and clinically significant.

So this is big if true.

------
jeroenhd
I fear that the second this hits major mainstream media, all vitamin D
capsules still left in stores will immediately be hoarded by the same people
who hoard toilet paper...

~~~
avip
You're two steps behind. Who do you think pushed all these "nutritional
recommendations" ?

------
quotz
Vit D deficiency is omnipresent in today's society. Literally almost everyone
I know has it. Supplementing Vit D drastically changed my mood. Too bad public
healthcare in Europe, especially the NHS in the UK, doesnt recognize Vit D
deficiency as a problem.

~~~
globular-toast
I'm highly sceptical of it being anything but a placebo for most people. I
live in the UK so I'm a good candidate for deficiency but I don't actually
feel anything is wrong with me. Everyone thinks they are tired all the time
and their sex drive isn't as high as it could be. If I supplement vitamin D
the only thing it does is give me constipation. I'm sure there are some people
with actual deficiency, but if you're white and go outside sometimes you're
probably fine.

~~~
beagle3
There's a difference between sickness-causing deficiency and optimal level.
Most people are somewhere in between. If you tried and it didn't make a
difference, then you're probably around the optimal level.

However, the specifics do matter; see e.g.
[https://www.gwern.net/zeo/Vitamin-D](https://www.gwern.net/zeo/Vitamin-D) \-
this is n=1 but consistent with many other n=1 self-experiments I'm familiar
with; personally, my sleep is improved with increased protein consumption AND
10,000 IU D3 before 10AM (Both contribute; I've not gone about 10,000 IU, but
5,000 UI has a much lesser effect)

I have not find a peer reviewed time-of-taking-D3 paper when I looked, but D3
is recognized as a timing mechanism ("Zeitgebber") in many papers I've found.

------
peter_retief
Kind of expected if you consider
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5684962/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5684962/)

~~~
yellow_viper
Interesting, vit D deficiency and TB immunity both run in my family.

~~~
peter_retief
Sunshine has always been helpful for people with TB, I wonder if that is why
people get more chest ailments in winter, ie colds and flu?

------
jwilk
(2019)

~~~
coldtea
Vitamin D went out of fashion in 2020?

------
marban
Also consider combining w/ K2 (as MK-7) for better absorption.

