>Because physical exams are performed in mobile vans in NHANES, data could not be collected in northern latitudes during the winter; instead data were collected in northern latitudes during summer and in southern latitudes in winter. To address this season-latitude aspect of the NHANES design, we stratified the sample into two seasonal subpopulations (winter/lower latitude and summer/higher latitude) before examining vitamin D status.

Yeah, I'm not surprised that the rates for vitamin D deficiency were low.

>Less than 1% of the winter/lower latitude subpopulation had vitamin D deficiency (25-OHD <17.5 nmol/L). However, the prevalence of vitamin D insufficiency in this group ranged from 1%–5% with 25-OHD <25 nmol/L /.../, even though the median latitude for this subsample (32°N) was considerably lower than the latitude at which vitamin D is not synthesized during winter months (∽42°N).

and the more northern latitude in summer:

>With the exception of elderly women, prevalence rates of vitamin D insufficiency were lower in the summer/higher latitude subpopulation (<1%–3% with 25-OHD <25 nmol/L)

Now imagine if you lived in northern Europe around the 60th parallel, where the sun doesn't get high enough in winter to produce vitamin D.

Sunlight has many pathways in the body, and increased vitamin D levels are just one of those pathways. Swallowing one element of a many-element pathway cannot simulate the human synthesis of vitamin D! This should be obvious! Your car might not run because of bad needle bearings, but the solution is not to add them to the gas tank! First, you must always understand.

Sunlight / vitamin D is an especially aggravating issue because we have increasing amounts of research on how sun exposure improves general health. Sleep quality and regularity, mood, cancer incidence (as the article notes), eyesight, skin conditions, overall mortality, virtually every part of human health is improved by going outside. And when I say "improved" I mean improved to such a degree that it would blow 95% of prescribed drugs out of the water. See, for example, the Melanoma in Southern Sweden study where the highest sun exposure cohort had _half_ the all-cause mortality of the lowest group. Unfortunately the Western medical establishment is thoroughly captured by industry and you can't sell a pill that makes you go outside.

[0] https://news.ycombinator.com/item?id=42326209

The strongest evidence for Vitamin D is in people who are severely deficient. Bumping up to a normal range can provide some improvements.

The health influencers started noticing that the Vitamin D studies coming out weren't matching their original hype for Vitamin D, so many pivoted to trying to make claims that most people are severely deficient and just don't know it, which provides a convenient out to dismiss the studies that didn't pre-filter for people who were severely deficient. You can find waves of people on social media repeating the idea that almost everyone is Vitamin D deficient and encouraging high dose supplementation still.

Speaking to a doctor who runs Vitamin D labs as part of her annual physical screening process, she's now actually seeing more people who have excess Vitamin D than too little Vitamin D. Upon followup she discovers that patients have listened to a podcast about Vitamin D and started taking it regularly, unaware that they're pushing their levels into the range where it can start doing more harm than good.

Vitamin D is tricky because it lasts for a very long time in the body, which means steady-state supplementation can take a very long time to stabilize. I suggest anyone supplementing for a long time get a blood test, which can be ordered without your doctor if you can't get your doctor on board.

On another topic: Fish oil has also gone through a similar cycle of being hyped up based on early results, with higher powered follow on studies showing much less interesting results.

https://pmc.ncbi.nlm.nih.gov/articles/PMC5541280/

https://pubmed.ncbi.nlm.nih.gov/33549285/

Look at the molecular structure

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

that's a freakin' steroid with one of the bonds in the rings deleted

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

[1] https://pubmed.ncbi.nlm.nih.gov/32918215/

[2] https://karger.com/bpu/article-abstract/41/1-3/130/328295/Su...

I never heard that in Germany. I only heard that if you use certain medications like cortisone that vitamin d could be problematic. Most doctors will give vitamin d supplements when prescribing cortisone, at least in Germany.

So whilst you may be able to take a supplement to boost your vitamin D levels, the negative health effects of lack of sunlight are still going to occur.

As someone who grew up in a European country where we don't get long summers, I suffered no demonstrable issues from the lack of sun nor did the many around me.

My family wasn't rich so food was reasonably nutritious but not perfectly balanced either.

Vitamin D supplements are sold widely, including in smaller supermarkets like Lidl and Aldi. And one imagines it all comes out of the same few factories.

There will be some who do need it, but not as many as are led to believe they do.

However, I need to get more sunlight; I just don't think supplementation is the same as being in the sun. When I was homeless I never had these mood issues, but that's complicated, living day-to-day & meal-by-meal puts you survival mode so nothing is really past the hour.

All anecdotal, duh.

https://news.ycombinator.com/item?id=17638508

I ultimately stopped it because it seemed to cause lower back aches. (Pretty sure, bone/muscle not kidney!) Every time I went on the D3, my back would start to hurt. That repeated several times, enough to suspect a pattern.

The cause may be similar to the itchy, tingling teeth.

According to this fascinating paper, Vitamin D can actually trigger the leaching of calcium out of bones, into circulation:

https://pmc.ncbi.nlm.nih.gov/articles/PMC8147670/

After the abstract, find the section heading "Vitamin D mobilizes calcium from calcified bone".

But that is in very high, pharmacological doses. Not your 5000 UI per day.

That trial used a dynamically-adjusted dosage of a vitamin D3 supplement, where dosing was set as to keep blood levels within a target range of 40–80 ng/mL. IMO part of the reason this trial is showing better results than the previous clinical trials of vitamin D supplementation quoted in the above article is that vitamin D has bad effects if too low and too high. Adjusting the dose dynamically to achieve an optimal range gets you the benefits without some of the negative effects.

The very premise that loading up your body with "excess" vitamins beyond what you need is already pretty fraught. Building a house without enough lumber can lead to long term deficiency - but loading up a construction site with more materials than are needed shouldn't automatically be assumed to be good.

The reality is that the modern diet has already solved so many common nutrient deficiency diseases (pellagra and goiters were a shockingly common diseases 100 years ago) that maxing out on vitamin intake has become more of something like a speculative hobby than anything else.

The article opens with the observation that southern states had lower cancer rates due to solar irradiance. But then we intervene by taking pills. Why not try to absorb through the skin, even if it means something like a tanning bed?

And if link is allowed https://sci-hub.ru/https://doi.org/10.1093/ije/9.3.227

I think a good hypothesis for the discrepancy regarding why people with "naturally" high levels of vitamin D fare better than those who do not has to do with how vitamin D is produced naturally.

If you take the vitamin orally it might help for rickets and a few other issues but if you take it naturally via sunlight you might actually be having other benefits that aren't properly measured today.

With the current state of fear surrounding sunlight I doubt people are getting enough to see benefits and all studies use oral supplements instead of time in sunshine.

More importantly, I'd like to know how long it takes to write a post like this.

Everything I write, I try to research and publish in under 2 weeks.

This post looks like it grew over time. I like that quality very much.

Why not?

Bones take calcium from bones? Net effect 0 then?

For example, I've been supplementing with nicotinamide riboside for a few years now. I stop occasionally and when I do stiff and sore hands and knees return and I get more headaches.

I'd love to know if I'm deluding myself (placebo effect?) or there's good science that backs up my experience.

Skip the D2 vitamin.

Lame. It started like enjoying an encyclopedia and ended like getting my face punched by a narcissistic robot who might have lied about facts and gave no way to spot check except redoing the entire article again myself from scratch. A novella on biophysics and no works cited?

Reading 7k words on biophysics with supposed data and science facts and getting hit with dozens of self reference footnotes instead of external citations is offensive to my intelligence.

I do not have the karma for the downvote button so I shall simply leave this.

Vitamin D is rat poison. The stuff they use in randomly controlled trials is not the stuff your body makes on its own. Too much sun and skin produced vitamin will not kill you. Too much rat poison will.

Real human research per the Material Safety Data Sheets with zero slop:

https://chemtrails.substack.com/p/vitamin-d-is-rat-poison-th...

but taking more than 2000iu per day is not just pointless but dangerous without blood testing

Vitamin D won't cure anything once there is a disease or illness

but it does show some preventative benefits

whole lotta people on Reddit do have blood tests showing it's way too low but those of course are the loudest voices

Rickets still occurs in Africa with abundant sunlight, but with polio still present. (The strains that come from vaccines are usually not counted.)

Note that adequate magnesium is critical for proper vitamin D function, but the article doesn't document it.

As somebody who spends an insane amount of time inside, the lack for exposure to the Sun mot just affected vitamin D levels but eyes sight too, they were terrible, and also mood.

Taking vitamin D pill instead of Sun is not the same.

I had ventricular extrasystoles for a very long time of my life (18-37). This is a mostly harmless arrytmia that feels like one beat out of the normal rhythm. Around 18, I noticed it for the first time. It came and went, usually I had this for ~3 weeks and then it was gone. Over the years however, I got more and more of those and at the age of 30, I had them ~70% of the year at a rate of 5-6/min. In parallel, I felt stressed and depressed. Not from the fact that I had those, I got used to that over the years, which was not easy.

The doctors I went to said: Harmless, learn to live with it, you will still get very old. Especially the five cardiologists but also the "normal" doctor I saw never took that serious at all. I kept a diary over the years and knew that those could fully go away and I had the feeling that it was somehow correlated with what I eat. Whenever I said that, the response was: "Unlikely, you just don't pay enough attention and do not notice them anymore". Treatment advice was: Live with it or get a catheter ablation done.

Then I then went to a different doctor who actually listened to me when I said they could fully go away. She tested me for vitamin D, B12, magnesium, potassium, iron and a few other things. It turned out that I had a strong vitamin D deficiency (12 ng/ml) and a mild MG/K/B12 deficiency.

Then I took some supplements (a bit of D/MG/K/B each). That helped a bit, but not always and not consistently, but I could definitely tell that there was a relation to taking something or not. I prefer a healthy diet over supplements, so I was not very consistent taking those and when everything was good I simply stopped. The fact that this did help, but not always, kept bugging me though and I wanted to figure out what exactly helped. Long story (~5 years of experimenting) short: It most likely was the combination of D and MG, taking one in isolation did not always improve things. There seems to be a mutual dependency between them, which also seems to be studied to some extend (I started to read med publications at some point, e.g. [0]), but I am a computer scientist and not a doctor so take this with a grain of salt and definitely do not just take stuff without measuring the actual levels first.

Today, I occassionally take supplements (still do not like the idea of taking them on a regular basis) and get my D level tested every once in a while. It is now usually ~30 ng/ml which is still a bit low, but the extrasystoles are fully gone (I am 44 now).

[0] Role of Magnesium in Vitamin D Activation and Function, https://pubmed.ncbi.nlm.nih.gov/29480918/