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There is a whole body of research around the ways that vitamin D modulates inflammation, helps regulate calcium homeostasis and strengthens circadian rhythm. Here is some relevant research:

- vitamin D is directly involved in regulating the renin-angiotensin system, including ACE2 expression. ( https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3999581/ )

- vitamin D has been shown to have anti-inflammatory activity with respect to cytokines specifically involved in advanced COVID-19 cases ( https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6164284/ )

- vitamin D and magnesium insufficiency both cause hypocalcemia, which has been connected to COVID-19 severity: ( https://www.researchsquare.com/article/rs-17575/v1 )

- magnesium and vitamin K2 also modulate calcium homeostasis ( you can look this one up yourself I need to get off this phone )

^^^ this is a snippet from a letter I sent to the local health department. I sure hope someone read it!

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I keep seeing data points like this, but does supplementing vitamin D work? Does it make sense to read things like this and conclude that taking a vitamin D supplement pill daily is a good idea?

If you are deficient, yes. If you are any vitamin or mineral dificient you should supplement. What this article says is: it is important, here's how much.

It just shows a strong correlation regardless of other factors such as demographics. The causation of such correlation is not yet determined. Although its probably a good idea to make sure you're not deficient whether or not vitamin D has an effect

N=1 I noticed a huge immediate positive shift in subjective well being when I started on vitamin D.

I cycle 4k iu of vitamin d daily during the darker winter months to keep my mood from tanking. Works every time.

Yep, I’ve noticed the same correlation. Whenever I’m going through a longer stint of feeling down. It’s usually because I’ve stopped taking vitamin d. I’m reasonably convinced there is some kind of correlation.

There is a long history of taking pills of vitamins and minerals not being as good as getting it the way we evolved for. We evolved to produce vitamin D by getting sunlight. We are NOT evolved from nocturnal animals. A vitamin D supplement might help, but a better idea is to take a walk in the park every day, while the sun is up.

Sure, and that's great, but what about the scenarios in which I cannot walk to the park (during 600+ AQI wildfires, as an example), is the reason I'd like the data on supplementation.

You can buy or make a SAD/Sun Lamp.

Most 'sun lamps' do not emit UVB, which is required for your body to make vitamin D.

Then don't buy those if your looking for that feature?

you're missing the point; he's saying that sun lamps don't have the same effect as the sun. This isn't just a "feature" that some lamps have and others don't; it's a crucial missing ingredient that results in the sun lamps you are suggesting simply _not working_.

No, I'm not. There are UVB generating light sources and they also fall under the SAD/Sun lamp definition.

Sure, and that's great, but I'm asking about the efficacy of a supplement

You're never going to get sensible dietary advice on HN.

Get sun. If you can't get sun you should eat a variety of food that contains vitamin D. If you can't do that, you should take a supplement. Take the supplement at the same time as you eat a meal, preferably a meal that has some fat.

Here's the advice for England:

https://www.nhs.uk/live-well/healthy-body/how-to-get-vitamin...

https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-...

Freely available advice from the UK's NHS would seem to be a good idea. We fund the NHS mostly out of taxation, so advice provided there has to be as close to non partisan as is reasonably possible.

I personally don't give a shit if you are a foreigner. If the NHS website can provide good advice and help someone - anyone, then my tax squids are being put to good use.

There are bound to be other good sources of health related advice around the place but why not start with the NHS and work out from there?

If you pay close attention, health authorities always play it safe, for example by saying "there's not enough evidence". That's why they didn't recommend masks in the beginning.

Then, if some sort of expert consensus comes up, the authorities adopt that. When that consensus is challenged by new evidence, authorities are slow to change, because that would be implicit admission that they were giving the wrong advice, which is not something that the human egos involved there can easily stomach.

A good example for this is the food pyramid[1]. It was never supported by good evidence, it was adopted through expert consensus (one might also call it lobbying), and it was later removed from the guidelines. You can still see posters of it hanging in doctor's offices, of course.

[1] https://en.wikipedia.org/wiki/History_of_USDA_nutrition_guid...

True that, but the incentives for government bureaucrats in the U.S. and the U.K. are somewhat different. Of the two, the former seem more likely to be swayed by industrial concerns/lobbying. Not saying that the U.K. is totally immune to this kind of thing, but I'd trust the NHS over the USDA.

> I'd trust the NHS over the USDA

Yet, the UK essentially adopted the advice given by the USDA. Why? Expert consensus is formed by research, which is usually funded by interest groups, and a lot of it ultimately comes out of the pockets of US industry.

For instance, the lipid hypothesis (that cholesterol causes heart disease) has been popularized once (with US industry support), became expert consensus, despite lack of evidence to support it, despite lots of contradictory data.

Once something is expert consensus for a while, it becomes harder and harder to challenge. At that point, there is no need for industry to control the narrative anymore, the experts (who do not want to admit being wrong) will control it all by themselves.

The point I am making is that the authorities are the last ones to set things right, their advice is forever outdated and therefore likely wrong.

> You're never going to get sensible dietary advice on HN.

> If you can't get sun you should eat a variety of food that contains vitamin D.

It's admirable that you prove your own point two sentences later.

> You're never going to get sensible dietary advice on HN.

You're never going to get sensible dietary advice, period. Diet is a belief system. Most people, including doctors and health authorities, really just go by clichés, like "eat five a day" or an unspecific "balanced diet". The science on it is poor and forever will be.

> If you can't get sun you should eat a variety of food that contains vitamin D.

Half an hour in the sun, if you are light-skinned, can get your body to produce about 10,000IU of vitamin D. To get that amount in the diet, you would need to eat more than a pound of the right fish.

Diet can get you out of the "severely deficient" range, but almost certainly not into the healthy range.

> Here's the advice for England

They actually advise supplementation, but they err on the low end. The only way to know if you get enough vitamin D is to do blood tests, people react quite different to different doses and forms. One guy here reports 10,000IUs daily gets him to only 55ng/dl (high end of normal), whereas 5000IUs gets others above 70 ng/dl (possibly harmful). Vitamin D builds up over time, so one test is not enough.

Like a supplement for not getting enough sunlight? Supplement your lack of sunlight with appropriate spectrum inside.

It works, I'm not a sunshine person. I work for myself and I usually work after I wake up at noon because I usually stay up til 4 or 5am at night. I get very little outdoors sunshine. I had very low vitamin D. My doc recommended supplementation if I wasn't willing to become a daywalker and my vitamin D levels were perfectly fine after a month of supplementing with 5k IU. I have cut back to 2K IU per day and my vitamin D levels are great since (5 years since I started supplementation).

These days those are called Oracle Lamps.

Here in Tasmania, and given the tone of my skin, in order to get enough sun exposure to provide for my vitamin D requirements...

I will spend enough time in the sun to damage my skin and significantly increase the risk of melanoma.

"There are some people (who are typically not dermatologists or experts in the biology of skin cancer) who have advocated for tanning to get vitamin D. But we know that UVB light causes skin cancer and that protecting yourself against it makes sense. As a doctor who treats patients who have melanomas, I want the general public to be advised that under no circumstances can use of a tanning bed or tanning in general be justified on the basis of vitamin D. Take a supplement instead."

https://www.yalemedicine.org/stories/vitamin-d-myths-debunke...

I heard tanning in short doses is actually ideal to prevent melanoma and procure the best vitamin D intake.

By exposing more of the skin, you absorb more vitamin D quicker, and so if you tan only 5 to 20 minutes depending on your skin complexion, you basically avoid skin burns and excess damage which causes melanoma and you get the benefits of the sun.

What do you think of this?

Edit: Maybe not what people think of as tanning, but it's basically skin exposure to the sun where you want to limit how long each part of the skin is exposed, but maximise the surface area for vitamin D absorbtion.

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

After having my bloodwork show that I had low vitamin D levels a few years ago, I was told by my physician that under no circumstances should I be getting vitamin D from the sun (as risking cancer was not worth it) and to wear sunblock everytime I go outside.

Frankly, I don't have the time to do an extensive literature search to find primary sources but I have seen from plenty of tertiary sources that it is a poor idea to get vitamin D from the sun. Moreover, there are plenty of foods from which you can get vitamin D.

This is the source that first got me curious about this: https://www.outsideonline.com/2380751/sunscreen-sun-exposure...

There's quite a bit of research that seem to coroborate it.

Sun can cause melanoma, but lack of sun also has negative effects albeit harder to track. Some even unrelated to vitamin D, as it seems the Sun does more than just provide us with vitamin D.

But it seems that the research on melanoma actually indicates that it is sunburn that is the prime cause. And sun exposure while under 20 is another leading cause. But after that, exposure that does not result in burn, like short term exposure doesn't seem to cause melanoma and does provide other health benefits.

I recommend a read in any case.

Not saying to go wild sun tanning, but I think if you can avoid burn (even minor ones), you're good.

Being that we are extant mammals we are evolved from nocturnal animals, just that not recently. Primates diverged to be more diurnal.

https://en.wikipedia.org/wiki/Nocturnal_bottleneck

Some of us don't want to do that so we take vitamin D supplements and we're just fine. "Nature is always better" cult is really just magical thinking. I'm not saying that one shouldn't go for walks in the sun or that it's not healthy, but that's an individual's choice.

This would seem to indicate that for Covid19 the answer is yes: https://www.sciencedirect.com/science/article/pii/S096007602...

Small sample size but the effect seems large.

I have an inflammatory condition, and one of the things my rheumatologist checks is my inactive vs. active vitamin d levels (apparently there are two chemical forms that your body converts between). My poor understanding is that folk with inflammatory issues often have disproportionately high levels of the active form, and too much of it causes damage to the body. Most blood labs only measure the inactive form, though, and so taking vitamin D supplements based on levels from the wrong blood test could be risky.

There are a lot of studies that demonstrate taking daily Vitamin D supplements reduces the likelihood of lung infections.

Moreover, the first double blind clinical trial on Vitamin D and COVID-19 was published [0] which had astonishing results:

N=76

Percentage admitted to ICU: 50% -> 2%

Deaths: 8% -> 0%

I suggest you read the paper for the full picture, or to watch the analysis of Dr John Cambell [1] There’s more and more studies like this that demonstrate that Vitamin D helps prevent bad outcomes. In other words: people who are Vitamin D deficient are much more likely to develop severe complications after contracting COVID-19. 42% of Americans are Vitamin D deficient. For African Americans that percentage is 82%, because darker skin makes Vitamin D more slowly.

In Europe we are going through a 2nd wave of infections, yet the death-rate is much lower than the first wave. This could be explained by the lower Vitamin D deficiency in most people thanks to the summer.

For what it’s worth, I am taking 25mcg/day of Vitamin D supplement. They are dirt cheap (5Eur for 300 days). Dr John Cambell is taking 50mcg and an email from Dr Fauci revealed that he is taking 150mcg/day [1].

So even if you get exposure to sunlight, I would suggest looking into taking a supplement. Why the main media/government channels don’t talk about this more is baffling and potentially criminal. Maybe because there’s no money to be made from Vitamin D because there are no patents?

[0] https://www.sciencedirect.com/science/article/pii/S096007602...

[1] https://youtube.com/watch?v=V8Ks9fUh2k8

> Why the main media/government channels don’t talk about this more is baffling and potentially criminal. Maybe because there’s no money to be made from Vitamin D because there are no patents?

Or perhaps the supplies would run empty if this became big news (?)

Wouldn't that be a good thing for supplement manufacturers? They can charge more due to the scarcity.

It's definitely getting out there anyway, in my local Boots the entire vit D section was empty, still a few bottles of the more expensive versions left (e.g. gluten free versions).

Yes, but supplement manufacturers can't make health claims.

Vitamin D is extremely cheap, so I assume it is very easy to manufacture. It's also freely available in a lot of different stores. So I doubt there would really be a shortage.

Additional data point: In Belgium, it's encouraged to give your children daily Vitamin D supplements until the age of 6. That tells me that there is scientific consensus about the safety, and that there is a large supply of it.

How did you arrive at 25mcg (1000 IU)?

Dr John Cambell did a video on Vitamin D dose [0]. Also, the daily Vitamin D supplements that are freely available are typically in the 15~30mcg range.

[0] https://www.youtube.com/watch?v=Bga_qG30JyY

I would like to point out the limitations of the linked paper (you can follow along in the discussion section of the paper). Hopefully this can generate enough discussion on how to better design studies like this in the future:

1. Statistically significant difference in patients with documented hypertension in the no-vitamin-d group (p value 0.002, 15 vs 11 patients)

2. 2:1 randomization, reducing statistical power. They do not document the sample size needed from a power analysis looking for power > 0.80. They basically assumed that twice as many people without vitamin D would end up in ICU, when in reality 13x as many people ended up ICU. In general, I wish we could have a larger sample size for studies like this, but I know it isn't practical.

3. Biggest for me is no baseline serum vitamin D level recorded, just an assumption that patients selected were overall vitamin D deficient based on population. Seems like a simple enough test that could have been run as a send out test (no need to have the level during hospitalization, just for data gathering purposes).

4. Not placebo controlled, would have helped as placebo effect is real. For all we know, giving the research medication could have meant that the patient received more care and supervision, potentially aiding in their hospital course.

Correct. The sample population was also limited. IIRC the main conclusion of the study is that larger scale studies should be conducted.

Every study has limitations. Do you feel that the limitations you stated mostly invalidate the study?

Nevertheless, like the professor of medicine at Harvard Medical School JoAnn Manson stated in May 2020 [0]: "The evidence is becoming quite compelling [that good Vitamin D status will protect against severe complications]".

[0] https://www.medscape.com/viewarticle/930152

Effect size matters as well, not just sample size. The effect size in this paper is huge.

Sure. It's not a perfect experiment. But the result of 2% vs. 50% ICU admission is astounding. And sure, the sample size is small so it could have arisen by chance (not very likely though). Personally until I saw this result I listened very patiently and mostly agreed with the people who argued correlation vs. causation, lack of data, or random other non-data backed arguments. I think now the balance of the scale has shifted towards until proven otherwise I'm gonna be supplementing vitamin D and if I do get sick with Covid19 I'm going to be asking for this as part of my treatment. And if placebo is so strong here, then I'll get my placebo effect anyways ;) Until there's conflicting evidence or more studies I think that's a reasonable position/risk balance.

I think that's a pretty fair assessment, there's generally minimal risk at normal dosages you find in the store (1000IU or whatever). If you're really concerned, a quick visit to the doctor to get baseline labs is a good way to make sure you're not gonna verge on toxicity.

The other worry on taking vitamin D supplements is that people go overboard with them and end up with too much vitamin D. I'd consider that to be good evidence that you're not just making expensive pee

It absolutely works. I had very low vitamin D (hadn't had a checkup in a few years), and was completely normal within a month of starting a regime of 5000IU per day I was completely normal, so yeah just plain old capsule vitamin d works. I cut back and now take 2000IU a day and have been going in for regular checkups and it's been perfectly normal since.

I think like most Vit, Vit D supplementation works for those deficient.

Isn't going to do much for those not deficient.

You should get your vitamin d levels tested, and then supplement. I feel that I go outside a fair bit, but to get my vitamin D levels up I have to take 10,000IU per day. Now my Vitamin D is about 57 ng/mL. The daily recommend amount on the supplement bottles isn’t going to come anywhere near to cutting it, especially if you spend most of your time inside or live up north.

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