11 ms·

The worthlessness of Vitamin D is mildly exaggerated

385 points by surprisetalk 4mo ago

cpncrunch 4mo ago
Even so, it still seems to be a small effect. The author mentions some studies looking at sunlight vs all cause mortality. These, and more recent studies [1] found much higher reductions in all cause mortality from sunlight exposure, of about 30%. It's thought that other factors may be behind this, such as NO production in the skin in response to UV [2]. [1] https://pubmed.ncbi.nlm.nih.gov/32918215/ https://pubmed.ncbi.nlm.nih.gov/32918215/ [2] https://karger.com/bpu/article-abstract/41/1-3/130/328295/Sunlight-Has-Cardiovascular-Benefits-Independently?redirectedFrom=fulltext https://karger.com/bpu/article-abstract/41/1-3/130/328295/Su...
- Aerroon 4mo ago
  Sunlight would likely get you all the "red light therapy" effects too.
nilirl 4mo ago
I like this author but this post was only weakly intriguing. 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.
- dynm 4mo ago
  > I'd like to know how long it takes to write a post like this. In this case, about three weeks.
amanaplanacanal 4mo ago
I suspect that blood vitamin D is mainly a marker for how much outdoor exercise people are getting, and that it is the exercise rather than the D which is causal.
- fragmede 4mo ago
  But then why do we see improvements in people that get vitamin D + K2 supplements and not exercise?
  - amanaplanacanal 4mo ago
    As the article mentions, we pretty much don't see improvements with supplementation.
    - criddell 4mo ago
      From the article: > the balance of evidence tips pretty clearly in the direction that people with low-ish levels would be wise to supplement
    - rzz3 4mo ago
      I don’t think there’s anything definitive. 400IU/day from one study is nothing if you’re deficient. 2000IU from another study is better, but even then we don’t seem to know much about absorption from these studies. For example, did it actually raise serum levels by 10ng/ml after a year, and how did THAT correlate to positive or negative health outcomes? K2 also seems to play an important symbiotic relationship with D, and seems notably absent from these studies.
      - adgjlsfhk1 4mo ago
        if supplements don't absorb and therefore don't affect health, there's no reason to take them.
        grep_name 4mo ago
        You missed the K2 part of his comment though. Both my mother and I have chronically tested incredibly low for vitmain D, both always taken supplements, both never had improvement. A couple years ago, my mom texted me saying she tried a D3+K2 supplement and for the first time in her life tested in range for vitamin D on her panel. I was skeptical but tried it, and have tested in normal range since.
Aurornis 4mo ago
This is a refreshingly balanced and honest analysis of Vitamin D studies. 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.
- thaumasiotes 4mo ago
  > 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 Not really. It isn't possible to be severely deficient in vitamin D without knowing it. By definition, if you are severely deficient in vitamin D, you have rickets.
- dyauspitr 4mo ago
  On a slight tangent, if people are unaware, you can pay for and get just about any lab test without a prescription in the United States.
  - 4mo ago
fred_is_fred 4mo ago
I didn't see any mention of K2 (or missed it) - but a lot of D supplements combine with K2 as a "traffic cop" to keep calcium in bones and not arteries. I've not found a ton of evidence on this either, but seems to be a popular combination.
brandonb 4mo ago
Another more recent trial (TARGET-D) is showing a 52% reduction in heart attack risk: https://www.empirical.health/blog/vitamin-d-heart/ https://www.empirical.health/blog/vitamin-d-heart/ 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.
- adrian_b 4mo ago
  That blood level matches what the parent article cites as typical for Africans who were still eating their traditional food, and which is higher than typical for the industrialized countries.
rzz3 4mo ago
Has anyone done a RCT of D3+K2? K2 seems to be important in the absorption of D3. Another aspect that bothers me with these studies is that we’re simply supplementing the vitamin D, seemingly without measuring the change in blood levels. I took 2000IU (+K2) a day for many years in between testing my blood levels and still had <30ng/ml and had to go up to 5000IU/day. I’d like to see some further study.
- nullc 4mo ago
  > I took 2000IU (+K2) a day for many years in between testing my blood levels and still had <30ng/ml and had to go up to 5000IU/day. Likewise, 23ng/ml while taking 2000iu/day of dry vitamin-d. Switched to 5000iu +K2 in MCT oil, -- 8 months later I'm at 64ng/ml.
  - rbjorklin 4mo ago
    Any noticeable difference how you feel health wise? Energy levels? Mood? Sleep quality?
    - _0ffh 4mo ago
      Not the same person here, but a data point nonetheless. Before supplementing D3 I had a cold basically every year, sometimes twice a year. Since I brushed up my levels I average 1 cold in 6 years.
      - ww520 4mo ago
        Oddly, since the Covid time, I haven't caught a cold or flu once. I'm not sure it's the vaccines, the flu shots, or the less physical contacts on things overall. I still go to crowded places from time to time, like plane or train rides. May be the population in general have less cold or flu virus overall to go around.
    - nullc 4mo ago
      Unfortunately too many other changes happened at the same time. I am enormously healthier now (in numerous measurable as well as subjective ways) but it may be that the D levels played no role.
OutOfHere 4mo ago
Just mildy exaggerated? Is this a joke article? If you don't achieve a suitable level, health will suffer immensely, even permanently. There are no ifs and buts. People who say otherwise work for the medical industrial complex and will get you killed. Note that adequate magnesium is critical for proper vitamin D function, but the article doesn't document it.
- gblargg 4mo ago
  Same for breathing oxygen, if you don't get it you'll die, but for most people oxygen supplementation would not be worth even knowing about.
  - OutOfHere 4mo ago
    That's an absurd analogy. Vitamin D is a vitamin that is in large part derived from significant sunlight exposure. Vitamins are essential by definition. Sunlight exposure is highly insufficient by historical standards. This is why supplementation is absolutely necessary in almost everyone who is not a full time outdoor worker. In contrast, the air contains oxygen which is sufficient for most people with normal lung function.
    - gblargg 4mo ago
      If most people have a significant Vitamin D deficiency, then I agree that my comparison was absurd.
      - d2kx 4mo ago
        Probably heavily depends on the country/region, but here in Germany it is basically the norm to be Vitamin D deficient. Like, half of the population have a deficiency when there is some sun and basically everyone has a deficiency for months during fall/winter/spring. So I have to laugh when I read "taking vitamin D does nothing unless you’re severely deficient". Yeah like, but that's most people in many countries lmao
      - OutOfHere 4mo ago
legitster 4mo ago
Your body needs vitamins in order to form complex aminos to operate. But your body only needs to make so many of them - especially if you are an adult, not pregnant, or not suffering from a disease of some sort. 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.
- UpsideDownRide 4mo ago
  Vitamin D deficiency entered the chat. It's a relatively common issue in many countries.
  - legitster 4mo ago
    That's fair, but it also exactly explains why there are weak positive effects of extra Vitamin D. There's a lot of unknowingly deficient people out there who get benefits from supplements. But the benefits are limited by the upper bound of the deficiency.
  - im3w1l 4mo ago
    Two things to consider: The recommended levels are established based on "good enough for 95% of people". That means that quite a lot of people can get by with less than the recommendation. Furthermore, being deficient is not a binary. If you are just a little bit deficient you may have very mild symptoms.
- PaulHoule 4mo ago
  Most vitamins are a cofactor for enzymes like https://en.wikipedia.org/wiki/Thiamine#Biological_functions https://en.wikipedia.org/wiki/Thiamine#Biological_functions Vitamin D is not but rather it regulates calcium and phosphorous metabolism.
criddell 4mo ago
This is great. I wonder if there's something like a patreon model where we could sponsor similar deep dives on other supplements? 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.
- js2 4mo ago
  examine.com
  - criddell 4mo ago
    Thanks! The results from examine.com for nicotinamide are interesting, but not as focused or concise (or usable) as the vitamin D information in this posting.
merb 4mo ago
> For a while there, many people thought vitamin D was magical 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.
- holistio 4mo ago
  Just two borders away, in Hungary, I've heard plenty of "magical vitamin D" tales. Tired? Take some D. Depressed? Take some D. Leg hurts? Take some D. I do take it in the winter, but I'm quite skeptical regarding the panacea hype.
Johnyjohnson123 4mo ago
People who say vitamin d isnt important should read about auld rickie...
Aerroon 4mo ago
The survey in the article that assessed vitamin D deficiency was a bit odd: >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.
- qurren 4mo ago
  Not to mention, northern latitudes get more sun that average in summer, and most northern countries have more reasonable working hours so people actually do go outside.
  - HPsquared 4mo ago
    More hours of sun, but it's less intense.
    - codethief 4mo ago
      The sun in northern countries in summer is less intense?
      - pdonis 4mo ago
        Yes, because it's lower in the sky so more of the UV in it gets absorbed by the atmosphere before reaching the ground. For example, in Florida in the summer, the sun is close to directly overhead at noon. In Scandinavia in the summer, the sun is only about halfway up the sky from the horizon at noon.
PaulHoule 4mo ago
It's arguable whether Vitamin D is really a vitamin or a hormone, see https://pubmed.ncbi.nlm.nih.gov/33549285/ https://pubmed.ncbi.nlm.nih.gov/33549285/ Look at the molecular structure https://en.wikipedia.org/wiki/Vitamin_D 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 https://en.wikipedia.org/wiki/Secosteroid
- brandonb 4mo ago
  It's pretty well-established science now that vitamin D is a hormone, not a true vitamin. Vitamin D binds a nuclear receptor that regulates roughly 1,000 to 2,000 genes (5-10% of the human genome). The "Vitamin D" moniker has just stuck around since it was named in 1922.
  - infinite_spin 4mo ago
    Yeah, it's just a holdover, the term "vitamin" originated from "vital amine", and vitamin D doesn't even have an amine group
    - raverbashing 4mo ago
      Well neither does Vitamin C.
      - PaulHoule 4mo ago
        It is a cofactor though https://en.wikipedia.org/wiki/Vitamin_C#Pharmacology https://en.wikipedia.org/wiki/Vitamin_C#Pharmacology
xutopia 4mo ago
Just because vitamin D supplements helps with rickets doesn't mean supplementation helps all the other things we seem to attribute to vitamin D. 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.
ninalanyon 4mo ago
> Because physical exams are performed in mobile vans in NHANES, data could not be collected in northern latitudes during the winter Why not?
- deleted 4mo ago
  [deleted]
- infinite_spin 4mo ago
  Probably due to road conditions during the winter season. Imagine asking someone who isn't used to driving on icy roads to drive a large van full of equipment up through the Rockies
  - floxy 4mo ago
    They plow the mountain passes in the winter time in at least Montana and Idaho. I'd be very surprised if they don't in Colorado or Utah.
    - bluGill 4mo ago
      They do, however the roads are, potentially icy, certainly after a storm, which means that you can't measure consistently, even if you're trying because some days the roads will be impassable. If someone's not used to driving in snow, it'll be even worse. You should not let them drive if there's snow/ice expected in the next day; or the roads haven't been cleared yet. As someone who grew up in Minnesota, I can tell you that yes, we are better at driving in snow than people down south. However, we go in the ditch a lot anyway.
atahanacar 4mo ago
Medical doctor here. Please don't get health advice from hn comments. As a matter of fact, I advice against reading anything about health on hn, as the risks of dangerous misinformation far outweigh any useful information you might learn here.
- kev009 4mo ago
  Halp us docter
- annzabelle 4mo ago
  There was a thread that touched on lyme disease recently, and there were a ridiculous number of comments going down pseudoscientific rabbit holes about people who'd somehow gotten chronic lyme in places with no endemic lyme disease and that the only ways to fix this were chronic antibiotics and hyperthermia chambers. HN often suffers from the trait of people who are really bright in one area assuming that that means they are really knowledgeable in areas they don't know much about.
  - atahanacar 4mo ago
    That is relatively benign compared to what I've seen before. I normally refrain from repeating misinformation, even for debunking it but I will make an exception (or two). I've seen comments ranging from "salt intake doesn't increase blood pressure because you pee what you don't need" to "blood glucose levels aren't good for diagnosing diabetes". Edit: OK, that's not really a "range". I have no idea why I phrased it like that. Both are very dangerous statements that can be life threatening if the wrong person believes it. I just hope that comment didn't cause any diabetic ketoacidosis cases.
- Bender 4mo ago
  Principal Armchair Commander here. I second this. That said I also avoid health advice from professionals. I have too often found their incentives to be in conflict with my well being. I just do my own research and ignore everyone, especially AI.
  - 4mo ago
vondur 4mo ago
I was taking 4000IU of Vitamin D daily along with 100 mcg Vitamin K-2 MK-7. My Vitamin D level was 60ng/ml. I've since dropped down to 3000IU per day. I go outside a lot but am either covered or using sunscreen since I sunburn easily.
- bethekidyouwant 4mo ago
  Pretty sure if you’re burning easily then you are making vitamin D easily so just go in the sun but not so much that you burn. (which is i think common sense)
persedes 4mo ago
Not in the field, but every time vitamin D studies come up I am reminded of the one that called out how current recommendations are based on faulty math (confusion on how to combine different sized studies confidence ranges ) and miss the mark significantly (and a lot of studies are based on those recommendations...) https://pmc.ncbi.nlm.nih.gov/articles/PMC5541280/ https://pmc.ncbi.nlm.nih.gov/articles/PMC5541280/
- nostromo 4mo ago
  To save people the click: the study says that the recommended vitamin D intake is much too low.
  - Etheryte 4mo ago
    Honestly you don't even need to know the recommended number. In many countries you can get tested for free, and if that's not the case for you, getting tested usually costs in the ballpark of a box vitamin D supplements. Measure and only then supplement, then measure again later. You don't need to fly blind.
    - anamexis 4mo ago
      A year's worth of daily 5000 IU (125 mcg) Vitamin D supplements costs approximately $15, so you could also just supplement.
      - tim-tday 4mo ago
        Strangely the protective effects of vitamin d for heart disease appear NOT to be achieved through supplements. (Though the protective effects for cancer ARE) I’m going to go out on a limb and guess that people who get outside a lot protect their health through both natural vitamin D from UV light exposure and cardiovascular exercise.
      - Etheryte 4mo ago
        This approach doesn't make much sense to me. Why supplement something when you don't even know that you need it? You could make the same argument about any and every supplement and eat the whole alphabet soup every day, but that's just putting extra strain on your body.
burnte 4mo ago
Ugh, more health pontificating from nonexperts. The blog is full of lame "hot takes." Blogspam, IMO.
jmhammond 4mo ago
In case the author is here, you can find the Garland & Garland (1980) article on sci-hub. And if link is allowed https://sci-hub.ru/https://doi.org/10.1093/ije/9.3.227 https://sci-hub.ru/https://doi.org/10.1093/ije/9.3.227
- gwern 4mo ago
  I expect the author is aware of that: where do you think he got the graph from if there's only 'gated copies'? But Sci-Hub links are unstable even if you don't mind linking them.
- elzbardico 4mo ago
  Linking to sci-hub for a known blogger may lead to undesired legal consequences in case the journal copyright mafia decides to make an legal example of you.
skyberrys 4mo ago
The charts showing vitamin D not helping, but also slightly hurting make the topic more relevant. The title is almost too flippant of the conclusions which is don't just take more than necessary,because it's likely to actively cause harm not just slightly increase your vitamin D.
innocentoldguy 4mo ago
Vitamin D is a lifesaver for me. I'm severely deficient, and if I don't take about 10,000 IU a day, I seem to get colds every five minutes.
- nullbio 4mo ago
  Have you tried going outside? Spend 15 minutes in the sun every day. It's not really that hard.
whycome 4mo ago
Leaving out skin colour from the conversations while mentioning 'randomized trials' and 'seasonal subpopulations' is problematic. Vitamin D production is highly tied to skin colour (melanin levels).
d2kx 4mo ago
Probably heavily depends on the country/region, but here in Germany it is basically the norm to be Vitamin D deficient. Like, half of the population have a deficiency when there is some sun and basically everyone has a deficiency for months during fall/winter/spring. So I have to laugh when I read "taking vitamin D does nothing unless you’re severely deficient". Yeah like, but that's most people in many countries lmao
rhipitr 4mo ago
Have a loved one that has extremely low vitamin D issues. Takes ergocalciferol from time to time and it is pretty useful in my opinion.
kazinator 4mo ago
I experimented with D3 supplementation up to almost a decade ago. I made some HN comments about it [2018]: https://news.ycombinator.com/item?id=17638508 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/ 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.
- dashmeet 4mo ago
  Not medical advice. You probably need to take vitamin d3 with k2 to avoid the calcium issues. Edited to add link https://pmc.ncbi.nlm.nih.gov/articles/PMC5613455/ https://pmc.ncbi.nlm.nih.gov/articles/PMC5613455/
green_wheel 4mo ago
I was told that there are lots of latitudes in North America where the sun is at too low an angle for your skin to make vitamin D for large parts of the year so you should take it during those times and then you should be fine during the summer if you get outside enough.
zhivota 4mo ago
Thousands of words and no mention of the obvious thing - testing whether sun exposure is beneficial or harmful. 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?
- chr15m 4mo ago
  Yep, it's sunlight. Nobody will run that trial though because we've spent decades telling people the sun is dangerous and gives you cancer (both things can be true of course). Putting people in the sun every day would not pass ethics tests. Also you cannot sell sunlight.
  - waysa 4mo ago
    > Also you cannot sell sunlight. Don't give them ideas.
- jerlam 4mo ago
  There are many nuances and people seem bad at understanding those. Too many are getting their information from "health influencers" and 30 second videos, which is why we seem to bounce between the two extremes of "everyone should take Vitamin D!" and "Vitamin D is overrated!". Australia has tried to explain sun safety here, taking into account that Vitamin D is best obtained from sunlight: https://www.cancer.org.au/cancer-information/causes-and-prevention/sun-safety/vitamin-d https://www.cancer.org.au/cancer-information/causes-and-prev...
  - zhivota 4mo ago
    Yeah not bad, though UV index of 3 is pretty comically low. Here in Manila it's basically full cloud conditions. I'd be interested to know a curve, i.e. at UV index 8, 3 minutes exposure, at index 6, 10 minutes exposure, etc. Maybe with a scaling for skin tone. It seems like either this kind of study has never been done (perhaps for ethical reasons) or else the information is not being disseminated. The latter seems to happen often in the medical space for paternalistic reasons, which honestly make sense for the broad public but it should be available for people to find who are motivated and have a deeper interest anyway.
h4kunamata 4mo ago
Misinformation. 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.
deleted 4mo ago
[deleted]
joehabeebs 4mo ago
I was told I was Vitamin D deficient and accidentally over indexed on supplements and got quite sick. Some of the dosages on OTC are ridiculously high
- toxicdevil 4mo ago
  A different personal experience. I had Vit D deficiency. Started on 2000IU per day and was still deficient after months. Then started on 5000IU per day, initially daily but now every other day or so. My last test was in the middle of the "normal" range. I have been taking VitD for 4 years or so. A lot of my symptoms like tiredness, sleepiness etc have improved since then. I asked my immediate family members to do a test as well. Male/female, young old, across states and even countries. All of them except my mother had low Vit D levels. My mother regularly supplements as its recommended for bone loss prevention in that age.
  - joehabeebs 4mo ago
    I was also taking 5K IU per day but had to tone it down after getting quite dizzy. I've been taking them every few days now and have yet to do a follow up but this is helpful to hear!
accidentallfact 4mo ago
What if rickets is actually a variant of polio, and vitamin D is just a hormone, and not a vitamin? Rickets still occurs in Africa with abundant sunlight, but with polio still present. (The strains that come from vaccines are usually not counted.)
lonelyrock42 4mo ago
I have HIV and am under treatment using medication, I have found D3 and K2 helps alleviate some of the side effects of the medication; largely my mood. Which makes a lot of sense because my immunity system is in constant daily activity. 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.
livingbuddha26 4mo ago
The veracity of this article depends on who paid you for it, if at all.
dippogriff 4mo ago
Vice versa, the exaggeration of vitamin D is mildly worthless. Some need supplements, some don't.
deepsun 4mo ago
I don't understand why literally everyone I know are diagnosed with Vitamin D Deficiency. Even living in sunny California. Wasn't human biology adapted for it in the last 40k years? I understand we spend more time indoors, but literally everyone?
- Gareth321 4mo ago
  We evolved to be in the sun for much of the day. We no longer do that. Many of us barely go outside at all anymore. Light skin is an evolutionary adaptation to mitigate the issues related to this in higher latitudes, but it's not match for modern indoor lifestyles.
owenversteeg 4mo ago
I have made this comment on HN many times [0] now but: it's the goddamn sunlight. 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 https://news.ycombinator.com/item?id=42326209
- remix2000 4mo ago
  Here in northern Europe, there just isn't enough sunlight to not become deficient, so a vitamin D supplement is a must.
  - b-zee 4mo ago
    I looked up data from a calorie tracking app I used a while ago and I got just enough vitamin D. Main sources were fish, eggs and dairy products. However, I ate a lot and I'm quite sure in winter there will have been periods where I didn't get the recommend intake. So if you live in a northern country and you don't like fish, I suppose it's quite a good idea to take a supplement. Though as OP said, even if the sun isn't strong enough, there are plenty of benefits to going outside beside vitamin D.
  - goda90 4mo ago
    Vitamin D is fat soluble, so it would be feasible to build up a supply in summer to last through winter. I've seen it theorized that a cyclical weight gain and loss tied to preindustrial seasonal food availability also plays a role.
Imanari 4mo ago
I started to take VitD on a whim and my mood and energy sure improved. Also I feel like I get sick less often. 3 friends whom I recommended VitD told me the same. Living in northern germany. YMMV.
- nullbio 4mo ago
  Placebo is a strong thing. Unless you're actually getting more sunlight, it's doing nothing for you.
  - Imanari 4mo ago
    I'll take it ;)
waffle-fry-pan 4mo ago
tl;dr: The combination of vitamin D/MG cured heart arrythmia and mild depression I suffered from for almost 20 years, so I do not think it is worthless. 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/ https://pubmed.ncbi.nlm.nih.gov/29480918/
tigerquoll 4mo ago
I rather liked his writing style - very easy to follow. He could have a future as a science communicator.
- fearnot 4mo ago
  [dead]
khurs 4mo ago
I think Vitamin D deficiency hype is driven by supplement sellers. 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.
- 2000UltraDeluxe 4mo ago
  As many other things, it depends on diet and lifestyle. I also live in the cold north, and generally, if you're fair-skinned, spend enough time in the sun and consume at least some products with natural or added vitamin D, you're usually good. Having a balanced diet and enough time to spend in the sun isn't a given, though, and many struggle getting enough vitamin D without suppments.
- nerbert 4mo ago
  tell that to the 90% of belgians with deficiency
- red-iron-pine 4mo ago
  a years supply of Vit D is like ~$30 you're telling me Big Vitamin is hustling the rubes that much? the reason it is commonly hyped is because it is in fact reasonably common, and because the fix is cheap and has no real side effects unless you take comically massive doses
AltruisticGapHN 4mo ago
All I know is I used to have full on colds during winter in my 20s to early 30s, like every winter I would get two weeks of runny nose till the skin became red and irritated, sore and painful throat, coughing, etc. Since I take 25000 IU (D-Cure in Belgium) like 2-3 times a month during winter for the past 15+ years my cold last 2-3 days and symptoms are much more mild. For me the data is there.
- epihelix 4mo ago
  The problem is that you don't know what your situation would be like if you'd not taken Vitamin D. There are too many variables, generally -- e.g. in your early 20s and 30s you're likely socialising with many more people (so, more exposure chances), and you may also have young children (even worse disease vectors). I'm similar to you in experience, btw, except that I don't believe correlation is causation. But as it won't do any harm, most of us don't regularly monitor our Vitamin D levels, and Vitamin D supplements are cheap -- it becomes a harmless form of Pascal's wager that I'm happy to keep making. Nothing to lose except a very, very tiny amount of money.
deleted 4mo ago
[deleted]
fearnot 4mo ago
Again, dynomight proves he's better than us.
m00k3r 4mo ago
[flagged]
crunchiepooker 4mo ago
[flagged]
bcjdjsndon 4mo ago
> and it will still tell your bones to scavenge calcium... So the body scavenges a lot of calcium from your bones... Bones take calcium from bones? Net effect 0 then?
- adrian_b 4mo ago
  Obviously that was an incorrect phrasing. The concentration of calcium ions in the extracellular water and in blood is always kept approximately constant. The bones are a reservoir of calcium in solid form, so whenever the concentration of calcium ions in the extracellular water drops the bones release calcium ions and whenever that concentration increases the bones retain calcium ions. This takes care of short term fluctuations. In order to also keep the amount of calcium stored in the bones approximately constant, the gut will try to absorb more calcium from the food when it is insufficient and the kidneys will excrete the excess, when it is too much.
voxleone 4mo ago
Quod abundat non nocet
economistbob 4mo ago
Thousands of words and no references list. Lame. Makes me suspect a piece written a bot. I have to dismiss almost all of it since there is no way to fact check and the article is filled with those asides that the bots put in there. The asides I refer to are the "are you still with me" and other psuedo-in-your-face punchy nonsense. Half the articles on the internet think I want backfill and history and punchy check-ins rather than the direct information that I used to scan through and obtain in about twenty seconds, but somehow those brand new AI slop sites are the top results on all engines (corruption since they sell services to generate those pages). 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-the-fraudulent https://chemtrails.substack.com/p/vitamin-d-is-rat-poison-th...
egberts1 4mo ago
methylcobalamin B-12 plus Vitamin D3 is the preferred form. Skip the D2 vitamin.
rizsyed1 4mo ago
I think taking a supplement every day is a good idea. I used to suffer from low vitamin D levels constantly until I started taking a daily vitamin D tablet.
ck2 4mo ago
the Vitamin D RDA is too low at 800iu 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
nullbio 4mo ago
Vitamin D is a biomarker of a process that happens in the body that is beneficial for longevity. This biomarker is created in response to receiving sunlight. The synthetic vitamin itself, does little, if anything, for your health. The process of receiving the sunlight is what benefits your health. This applies to a lot of other vitamin supplements as well. 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.
- redrove 4mo ago
  Do you have any sources for this? Genuinely interested in reading more.
  - xolox 4mo ago
    I've recently run into and explored research explaining that natural sunlight stimulates energy production in mitochondria, resulting in an energizing and healing effect completely separate from vitamin D production. I feel bad for posting this without references so here's one reference I could find right now: > This study shows that longer wavelengths in sunlight are transmitted through the body. When these are presented via NIR LEDs in a laboratory-controlled environment at much lower energies, they again have the ability to be transmitted through the body and also are associated with improved visual function independent of ocular exposure. Hence, body penetration by longer wavelengths impacts systemically. Longer wavelengths improve mitochondrial membrane potential and ATP production and improve function in a species conserved pattern that can impact on mobility, visual function and cognition, particularly in ageing. In short lived animals they can extend average life span. > Taken together, these data provide evidence of the importance of the full spectrum of sunlight for human health. They also highlight the potential dangers of the restricted spectra found in white LED lighting in the modern built environment that lacks longer wavelengths and whose output is generally restricted to around 400–650 nm. The absence of longer wavelengths from LED light sources may have implications for public health that should be addressed. Source: https://www.nature.com/articles/s41598-025-09785-3#Sec5 https://www.nature.com/articles/s41598-025-09785-3#Sec5
  - 4mo ago
euroderf 4mo ago
Early into the Covid pandemic, there was talk that vitamin D had some protective effect. Did this ever pan out into any kind of recommendation supported by evidence ?
- stevedt 4mo ago
  https://pmc.ncbi.nlm.nih.gov/articles/PMC8541492/ https://pmc.ncbi.nlm.nih.gov/articles/PMC8541492/
bingoMen 4mo ago
This is a very good, understandable article.

385 points by surprisetalk 4mo ago

Even so, it still seems to be a small effect. The author mentions some studies looking at sunlight vs all cause mortality. These, and more recent studies [1] found much higher reductions in all cause mortality from sunlight exposure, of about 30%. It's thought that other factors may be behind this, such as NO production in the skin in response to UV [2]. [1] https://pubmed.ncbi.nlm.nih.gov/32918215/ https://pubmed.ncbi.nlm.nih.gov/32918215/ [2] https://karger.com/bpu/article-abstract/41/1-3/130/328295/Sunlight-Has-Cardiovascular-Benefits-Independently?redirectedFrom=fulltext https://karger.com/bpu/article-abstract/41/1-3/130/328295/Su...

Aerroon 4mo ago
Sunlight would likely get you all the "red light therapy" effects too.

nilirl 4mo ago

I like this author but this post was only weakly intriguing. 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.

dynm 4mo ago
> I'd like to know how long it takes to write a post like this. In this case, about three weeks.

amanaplanacanal 4mo ago

I suspect that blood vitamin D is mainly a marker for how much outdoor exercise people are getting, and that it is the exercise rather than the D which is causal.

fragmede 4mo ago
But then why do we see improvements in people that get vitamin D + K2 supplements and not exercise?
- amanaplanacanal 4mo ago
  As the article mentions, we pretty much don't see improvements with supplementation.
  - criddell 4mo ago
    From the article: > the balance of evidence tips pretty clearly in the direction that people with low-ish levels would be wise to supplement
  - rzz3 4mo ago
    I don’t think there’s anything definitive. 400IU/day from one study is nothing if you’re deficient. 2000IU from another study is better, but even then we don’t seem to know much about absorption from these studies. For example, did it actually raise serum levels by 10ng/ml after a year, and how did THAT correlate to positive or negative health outcomes? K2 also seems to play an important symbiotic relationship with D, and seems notably absent from these studies.
    - adgjlsfhk1 4mo ago
      if supplements don't absorb and therefore don't affect health, there's no reason to take them.
      - grep_name 4mo ago
        You missed the K2 part of his comment though. Both my mother and I have chronically tested incredibly low for vitmain D, both always taken supplements, both never had improvement. A couple years ago, my mom texted me saying she tried a D3+K2 supplement and for the first time in her life tested in range for vitamin D on her panel. I was skeptical but tried it, and have tested in normal range since.

Aurornis 4mo ago

This is a refreshingly balanced and honest analysis of Vitamin D studies. 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.

thaumasiotes 4mo ago
> 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 Not really. It isn't possible to be severely deficient in vitamin D without knowing it. By definition, if you are severely deficient in vitamin D, you have rickets.
dyauspitr 4mo ago
On a slight tangent, if people are unaware, you can pay for and get just about any lab test without a prescription in the United States.
- 4mo ago

fred_is_fred 4mo ago

I didn't see any mention of K2 (or missed it) - but a lot of D supplements combine with K2 as a "traffic cop" to keep calcium in bones and not arteries. I've not found a ton of evidence on this either, but seems to be a popular combination.

brandonb 4mo ago

Another more recent trial (TARGET-D) is showing a 52% reduction in heart attack risk: https://www.empirical.health/blog/vitamin-d-heart/ https://www.empirical.health/blog/vitamin-d-heart/ 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.

adrian_b 4mo ago
That blood level matches what the parent article cites as typical for Africans who were still eating their traditional food, and which is higher than typical for the industrialized countries.

rzz3 4mo ago

Has anyone done a RCT of D3+K2? K2 seems to be important in the absorption of D3. Another aspect that bothers me with these studies is that we’re simply supplementing the vitamin D, seemingly without measuring the change in blood levels. I took 2000IU (+K2) a day for many years in between testing my blood levels and still had <30ng/ml and had to go up to 5000IU/day. I’d like to see some further study.

nullc 4mo ago
> I took 2000IU (+K2) a day for many years in between testing my blood levels and still had <30ng/ml and had to go up to 5000IU/day. Likewise, 23ng/ml while taking 2000iu/day of dry vitamin-d. Switched to 5000iu +K2 in MCT oil, -- 8 months later I'm at 64ng/ml.
- rbjorklin 4mo ago
  Any noticeable difference how you feel health wise? Energy levels? Mood? Sleep quality?
  - _0ffh 4mo ago
    Not the same person here, but a data point nonetheless. Before supplementing D3 I had a cold basically every year, sometimes twice a year. Since I brushed up my levels I average 1 cold in 6 years.
    - ww520 4mo ago
      Oddly, since the Covid time, I haven't caught a cold or flu once. I'm not sure it's the vaccines, the flu shots, or the less physical contacts on things overall. I still go to crowded places from time to time, like plane or train rides. May be the population in general have less cold or flu virus overall to go around.
  - nullc 4mo ago
    Unfortunately too many other changes happened at the same time. I am enormously healthier now (in numerous measurable as well as subjective ways) but it may be that the D levels played no role.

OutOfHere 4mo ago

Just mildy exaggerated? Is this a joke article? If you don't achieve a suitable level, health will suffer immensely, even permanently. There are no ifs and buts. People who say otherwise work for the medical industrial complex and will get you killed. Note that adequate magnesium is critical for proper vitamin D function, but the article doesn't document it.

gblargg 4mo ago
Same for breathing oxygen, if you don't get it you'll die, but for most people oxygen supplementation would not be worth even knowing about.
- OutOfHere 4mo ago
  That's an absurd analogy. Vitamin D is a vitamin that is in large part derived from significant sunlight exposure. Vitamins are essential by definition. Sunlight exposure is highly insufficient by historical standards. This is why supplementation is absolutely necessary in almost everyone who is not a full time outdoor worker. In contrast, the air contains oxygen which is sufficient for most people with normal lung function.
  - gblargg 4mo ago
    If most people have a significant Vitamin D deficiency, then I agree that my comparison was absurd.
    - d2kx 4mo ago
      Probably heavily depends on the country/region, but here in Germany it is basically the norm to be Vitamin D deficient. Like, half of the population have a deficiency when there is some sun and basically everyone has a deficiency for months during fall/winter/spring. So I have to laugh when I read "taking vitamin D does nothing unless you’re severely deficient". Yeah like, but that's most people in many countries lmao
    - OutOfHere 4mo ago

legitster 4mo ago

Your body needs vitamins in order to form complex aminos to operate. But your body only needs to make so many of them - especially if you are an adult, not pregnant, or not suffering from a disease of some sort. 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.

UpsideDownRide 4mo ago
Vitamin D deficiency entered the chat. It's a relatively common issue in many countries.
- legitster 4mo ago
  That's fair, but it also exactly explains why there are weak positive effects of extra Vitamin D. There's a lot of unknowingly deficient people out there who get benefits from supplements. But the benefits are limited by the upper bound of the deficiency.
- im3w1l 4mo ago
  Two things to consider: The recommended levels are established based on "good enough for 95% of people". That means that quite a lot of people can get by with less than the recommendation. Furthermore, being deficient is not a binary. If you are just a little bit deficient you may have very mild symptoms.
PaulHoule 4mo ago
Most vitamins are a cofactor for enzymes like https://en.wikipedia.org/wiki/Thiamine#Biological_functions https://en.wikipedia.org/wiki/Thiamine#Biological_functions Vitamin D is not but rather it regulates calcium and phosphorous metabolism.

criddell 4mo ago

This is great. I wonder if there's something like a patreon model where we could sponsor similar deep dives on other supplements? 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.

js2 4mo ago
examine.com
- criddell 4mo ago
  Thanks! The results from examine.com for nicotinamide are interesting, but not as focused or concise (or usable) as the vitamin D information in this posting.

merb 4mo ago

> For a while there, many people thought vitamin D was magical 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.

holistio 4mo ago
Just two borders away, in Hungary, I've heard plenty of "magical vitamin D" tales. Tired? Take some D. Depressed? Take some D. Leg hurts? Take some D. I do take it in the winter, but I'm quite skeptical regarding the panacea hype.

Johnyjohnson123 4mo ago

People who say vitamin d isnt important should read about auld rickie...

Aerroon 4mo ago

The survey in the article that assessed vitamin D deficiency was a bit odd: >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.

qurren 4mo ago
Not to mention, northern latitudes get more sun that average in summer, and most northern countries have more reasonable working hours so people actually do go outside.
- HPsquared 4mo ago
  More hours of sun, but it's less intense.
  - codethief 4mo ago
    The sun in northern countries in summer is less intense?
    - pdonis 4mo ago
      Yes, because it's lower in the sky so more of the UV in it gets absorbed by the atmosphere before reaching the ground. For example, in Florida in the summer, the sun is close to directly overhead at noon. In Scandinavia in the summer, the sun is only about halfway up the sky from the horizon at noon.

PaulHoule 4mo ago

It's arguable whether Vitamin D is really a vitamin or a hormone, see https://pubmed.ncbi.nlm.nih.gov/33549285/ https://pubmed.ncbi.nlm.nih.gov/33549285/ Look at the molecular structure https://en.wikipedia.org/wiki/Vitamin_D 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 https://en.wikipedia.org/wiki/Secosteroid

brandonb 4mo ago
It's pretty well-established science now that vitamin D is a hormone, not a true vitamin. Vitamin D binds a nuclear receptor that regulates roughly 1,000 to 2,000 genes (5-10% of the human genome). The "Vitamin D" moniker has just stuck around since it was named in 1922.
- infinite_spin 4mo ago
  Yeah, it's just a holdover, the term "vitamin" originated from "vital amine", and vitamin D doesn't even have an amine group
  - raverbashing 4mo ago
    Well neither does Vitamin C.
    - PaulHoule 4mo ago
      It is a cofactor though https://en.wikipedia.org/wiki/Vitamin_C#Pharmacology https://en.wikipedia.org/wiki/Vitamin_C#Pharmacology

xutopia 4mo ago

Just because vitamin D supplements helps with rickets doesn't mean supplementation helps all the other things we seem to attribute to vitamin D. 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.

ninalanyon 4mo ago

> Because physical exams are performed in mobile vans in NHANES, data could not be collected in northern latitudes during the winter Why not?

deleted 4mo ago
[deleted]
infinite_spin 4mo ago
Probably due to road conditions during the winter season. Imagine asking someone who isn't used to driving on icy roads to drive a large van full of equipment up through the Rockies
- floxy 4mo ago
  They plow the mountain passes in the winter time in at least Montana and Idaho. I'd be very surprised if they don't in Colorado or Utah.
  - bluGill 4mo ago
    They do, however the roads are, potentially icy, certainly after a storm, which means that you can't measure consistently, even if you're trying because some days the roads will be impassable. If someone's not used to driving in snow, it'll be even worse. You should not let them drive if there's snow/ice expected in the next day; or the roads haven't been cleared yet. As someone who grew up in Minnesota, I can tell you that yes, we are better at driving in snow than people down south. However, we go in the ditch a lot anyway.

atahanacar 4mo ago

Medical doctor here. Please don't get health advice from hn comments. As a matter of fact, I advice against reading anything about health on hn, as the risks of dangerous misinformation far outweigh any useful information you might learn here.

kev009 4mo ago
Halp us docter
annzabelle 4mo ago
There was a thread that touched on lyme disease recently, and there were a ridiculous number of comments going down pseudoscientific rabbit holes about people who'd somehow gotten chronic lyme in places with no endemic lyme disease and that the only ways to fix this were chronic antibiotics and hyperthermia chambers. HN often suffers from the trait of people who are really bright in one area assuming that that means they are really knowledgeable in areas they don't know much about.
- atahanacar 4mo ago
  That is relatively benign compared to what I've seen before. I normally refrain from repeating misinformation, even for debunking it but I will make an exception (or two). I've seen comments ranging from "salt intake doesn't increase blood pressure because you pee what you don't need" to "blood glucose levels aren't good for diagnosing diabetes". Edit: OK, that's not really a "range". I have no idea why I phrased it like that. Both are very dangerous statements that can be life threatening if the wrong person believes it. I just hope that comment didn't cause any diabetic ketoacidosis cases.
Bender 4mo ago
Principal Armchair Commander here. I second this. That said I also avoid health advice from professionals. I have too often found their incentives to be in conflict with my well being. I just do my own research and ignore everyone, especially AI.
- 4mo ago

vondur 4mo ago

I was taking 4000IU of Vitamin D daily along with 100 mcg Vitamin K-2 MK-7. My Vitamin D level was 60ng/ml. I've since dropped down to 3000IU per day. I go outside a lot but am either covered or using sunscreen since I sunburn easily.

bethekidyouwant 4mo ago
Pretty sure if you’re burning easily then you are making vitamin D easily so just go in the sun but not so much that you burn. (which is i think common sense)

persedes 4mo ago

Not in the field, but every time vitamin D studies come up I am reminded of the one that called out how current recommendations are based on faulty math (confusion on how to combine different sized studies confidence ranges ) and miss the mark significantly (and a lot of studies are based on those recommendations...) https://pmc.ncbi.nlm.nih.gov/articles/PMC5541280/ https://pmc.ncbi.nlm.nih.gov/articles/PMC5541280/

nostromo 4mo ago
To save people the click: the study says that the recommended vitamin D intake is much too low.
- Etheryte 4mo ago
  Honestly you don't even need to know the recommended number. In many countries you can get tested for free, and if that's not the case for you, getting tested usually costs in the ballpark of a box vitamin D supplements. Measure and only then supplement, then measure again later. You don't need to fly blind.
  - anamexis 4mo ago
    A year's worth of daily 5000 IU (125 mcg) Vitamin D supplements costs approximately $15, so you could also just supplement.
    - tim-tday 4mo ago
      Strangely the protective effects of vitamin d for heart disease appear NOT to be achieved through supplements. (Though the protective effects for cancer ARE) I’m going to go out on a limb and guess that people who get outside a lot protect their health through both natural vitamin D from UV light exposure and cardiovascular exercise.
    - Etheryte 4mo ago
      This approach doesn't make much sense to me. Why supplement something when you don't even know that you need it? You could make the same argument about any and every supplement and eat the whole alphabet soup every day, but that's just putting extra strain on your body.

burnte 4mo ago

Ugh, more health pontificating from nonexperts. The blog is full of lame "hot takes." Blogspam, IMO.

jmhammond 4mo ago

In case the author is here, you can find the Garland & Garland (1980) article on sci-hub. And if link is allowed https://sci-hub.ru/https://doi.org/10.1093/ije/9.3.227 https://sci-hub.ru/https://doi.org/10.1093/ije/9.3.227

gwern 4mo ago
I expect the author is aware of that: where do you think he got the graph from if there's only 'gated copies'? But Sci-Hub links are unstable even if you don't mind linking them.
elzbardico 4mo ago
Linking to sci-hub for a known blogger may lead to undesired legal consequences in case the journal copyright mafia decides to make an legal example of you.

skyberrys 4mo ago

The charts showing vitamin D not helping, but also slightly hurting make the topic more relevant. The title is almost too flippant of the conclusions which is don't just take more than necessary,because it's likely to actively cause harm not just slightly increase your vitamin D.

innocentoldguy 4mo ago

Vitamin D is a lifesaver for me. I'm severely deficient, and if I don't take about 10,000 IU a day, I seem to get colds every five minutes.

nullbio 4mo ago
Have you tried going outside? Spend 15 minutes in the sun every day. It's not really that hard.

whycome 4mo ago

Leaving out skin colour from the conversations while mentioning 'randomized trials' and 'seasonal subpopulations' is problematic. Vitamin D production is highly tied to skin colour (melanin levels).

d2kx 4mo ago

Probably heavily depends on the country/region, but here in Germany it is basically the norm to be Vitamin D deficient. Like, half of the population have a deficiency when there is some sun and basically everyone has a deficiency for months during fall/winter/spring. So I have to laugh when I read "taking vitamin D does nothing unless you’re severely deficient". Yeah like, but that's most people in many countries lmao

rhipitr 4mo ago

Have a loved one that has extremely low vitamin D issues. Takes ergocalciferol from time to time and it is pretty useful in my opinion.

kazinator 4mo ago

I experimented with D3 supplementation up to almost a decade ago. I made some HN comments about it [2018]: https://news.ycombinator.com/item?id=17638508 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/ 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.

dashmeet 4mo ago
Not medical advice. You probably need to take vitamin d3 with k2 to avoid the calcium issues. Edited to add link https://pmc.ncbi.nlm.nih.gov/articles/PMC5613455/ https://pmc.ncbi.nlm.nih.gov/articles/PMC5613455/

green_wheel 4mo ago

I was told that there are lots of latitudes in North America where the sun is at too low an angle for your skin to make vitamin D for large parts of the year so you should take it during those times and then you should be fine during the summer if you get outside enough.

zhivota 4mo ago

Thousands of words and no mention of the obvious thing - testing whether sun exposure is beneficial or harmful. 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?

chr15m 4mo ago
Yep, it's sunlight. Nobody will run that trial though because we've spent decades telling people the sun is dangerous and gives you cancer (both things can be true of course). Putting people in the sun every day would not pass ethics tests. Also you cannot sell sunlight.
- waysa 4mo ago
  > Also you cannot sell sunlight. Don't give them ideas.
jerlam 4mo ago
There are many nuances and people seem bad at understanding those. Too many are getting their information from "health influencers" and 30 second videos, which is why we seem to bounce between the two extremes of "everyone should take Vitamin D!" and "Vitamin D is overrated!". Australia has tried to explain sun safety here, taking into account that Vitamin D is best obtained from sunlight: https://www.cancer.org.au/cancer-information/causes-and-prevention/sun-safety/vitamin-d https://www.cancer.org.au/cancer-information/causes-and-prev...
- zhivota 4mo ago
  Yeah not bad, though UV index of 3 is pretty comically low. Here in Manila it's basically full cloud conditions. I'd be interested to know a curve, i.e. at UV index 8, 3 minutes exposure, at index 6, 10 minutes exposure, etc. Maybe with a scaling for skin tone. It seems like either this kind of study has never been done (perhaps for ethical reasons) or else the information is not being disseminated. The latter seems to happen often in the medical space for paternalistic reasons, which honestly make sense for the broad public but it should be available for people to find who are motivated and have a deeper interest anyway.

h4kunamata 4mo ago

Misinformation. 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.

deleted 4mo ago

[deleted]

joehabeebs 4mo ago

I was told I was Vitamin D deficient and accidentally over indexed on supplements and got quite sick. Some of the dosages on OTC are ridiculously high

toxicdevil 4mo ago
A different personal experience. I had Vit D deficiency. Started on 2000IU per day and was still deficient after months. Then started on 5000IU per day, initially daily but now every other day or so. My last test was in the middle of the "normal" range. I have been taking VitD for 4 years or so. A lot of my symptoms like tiredness, sleepiness etc have improved since then. I asked my immediate family members to do a test as well. Male/female, young old, across states and even countries. All of them except my mother had low Vit D levels. My mother regularly supplements as its recommended for bone loss prevention in that age.
- joehabeebs 4mo ago
  I was also taking 5K IU per day but had to tone it down after getting quite dizzy. I've been taking them every few days now and have yet to do a follow up but this is helpful to hear!

accidentallfact 4mo ago

What if rickets is actually a variant of polio, and vitamin D is just a hormone, and not a vitamin? Rickets still occurs in Africa with abundant sunlight, but with polio still present. (The strains that come from vaccines are usually not counted.)

lonelyrock42 4mo ago

I have HIV and am under treatment using medication, I have found D3 and K2 helps alleviate some of the side effects of the medication; largely my mood. Which makes a lot of sense because my immunity system is in constant daily activity. 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.

livingbuddha26 4mo ago

The veracity of this article depends on who paid you for it, if at all.

dippogriff 4mo ago

Vice versa, the exaggeration of vitamin D is mildly worthless. Some need supplements, some don't.

deepsun 4mo ago

I don't understand why literally everyone I know are diagnosed with Vitamin D Deficiency. Even living in sunny California. Wasn't human biology adapted for it in the last 40k years? I understand we spend more time indoors, but literally everyone?

Gareth321 4mo ago
We evolved to be in the sun for much of the day. We no longer do that. Many of us barely go outside at all anymore. Light skin is an evolutionary adaptation to mitigate the issues related to this in higher latitudes, but it's not match for modern indoor lifestyles.

owenversteeg 4mo ago

I have made this comment on HN many times [0] now but: it's the goddamn sunlight. 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 https://news.ycombinator.com/item?id=42326209

remix2000 4mo ago
Here in northern Europe, there just isn't enough sunlight to not become deficient, so a vitamin D supplement is a must.
- b-zee 4mo ago
  I looked up data from a calorie tracking app I used a while ago and I got just enough vitamin D. Main sources were fish, eggs and dairy products. However, I ate a lot and I'm quite sure in winter there will have been periods where I didn't get the recommend intake. So if you live in a northern country and you don't like fish, I suppose it's quite a good idea to take a supplement. Though as OP said, even if the sun isn't strong enough, there are plenty of benefits to going outside beside vitamin D.
- goda90 4mo ago
  Vitamin D is fat soluble, so it would be feasible to build up a supply in summer to last through winter. I've seen it theorized that a cyclical weight gain and loss tied to preindustrial seasonal food availability also plays a role.

Imanari 4mo ago

I started to take VitD on a whim and my mood and energy sure improved. Also I feel like I get sick less often. 3 friends whom I recommended VitD told me the same. Living in northern germany. YMMV.

nullbio 4mo ago
Placebo is a strong thing. Unless you're actually getting more sunlight, it's doing nothing for you.
- Imanari 4mo ago
  I'll take it ;)

waffle-fry-pan 4mo ago

tl;dr: The combination of vitamin D/MG cured heart arrythmia and mild depression I suffered from for almost 20 years, so I do not think it is worthless. 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/ https://pubmed.ncbi.nlm.nih.gov/29480918/

tigerquoll 4mo ago

I rather liked his writing style - very easy to follow. He could have a future as a science communicator.

fearnot 4mo ago
[dead]

khurs 4mo ago

I think Vitamin D deficiency hype is driven by supplement sellers. 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.

2000UltraDeluxe 4mo ago
As many other things, it depends on diet and lifestyle. I also live in the cold north, and generally, if you're fair-skinned, spend enough time in the sun and consume at least some products with natural or added vitamin D, you're usually good. Having a balanced diet and enough time to spend in the sun isn't a given, though, and many struggle getting enough vitamin D without suppments.
nerbert 4mo ago
tell that to the 90% of belgians with deficiency
red-iron-pine 4mo ago
a years supply of Vit D is like ~$30 you're telling me Big Vitamin is hustling the rubes that much? the reason it is commonly hyped is because it is in fact reasonably common, and because the fix is cheap and has no real side effects unless you take comically massive doses

AltruisticGapHN 4mo ago

All I know is I used to have full on colds during winter in my 20s to early 30s, like every winter I would get two weeks of runny nose till the skin became red and irritated, sore and painful throat, coughing, etc. Since I take 25000 IU (D-Cure in Belgium) like 2-3 times a month during winter for the past 15+ years my cold last 2-3 days and symptoms are much more mild. For me the data is there.

epihelix 4mo ago
The problem is that you don't know what your situation would be like if you'd not taken Vitamin D. There are too many variables, generally -- e.g. in your early 20s and 30s you're likely socialising with many more people (so, more exposure chances), and you may also have young children (even worse disease vectors). I'm similar to you in experience, btw, except that I don't believe correlation is causation. But as it won't do any harm, most of us don't regularly monitor our Vitamin D levels, and Vitamin D supplements are cheap -- it becomes a harmless form of Pascal's wager that I'm happy to keep making. Nothing to lose except a very, very tiny amount of money.

deleted 4mo ago

[deleted]

fearnot 4mo ago

Again, dynomight proves he's better than us.

m00k3r 4mo ago

[flagged]

crunchiepooker 4mo ago

[flagged]

bcjdjsndon 4mo ago

> and it will still tell your bones to scavenge calcium... So the body scavenges a lot of calcium from your bones... Bones take calcium from bones? Net effect 0 then?

adrian_b 4mo ago
Obviously that was an incorrect phrasing. The concentration of calcium ions in the extracellular water and in blood is always kept approximately constant. The bones are a reservoir of calcium in solid form, so whenever the concentration of calcium ions in the extracellular water drops the bones release calcium ions and whenever that concentration increases the bones retain calcium ions. This takes care of short term fluctuations. In order to also keep the amount of calcium stored in the bones approximately constant, the gut will try to absorb more calcium from the food when it is insufficient and the kidneys will excrete the excess, when it is too much.

voxleone 4mo ago

Quod abundat non nocet

economistbob 4mo ago

Thousands of words and no references list. Lame. Makes me suspect a piece written a bot. I have to dismiss almost all of it since there is no way to fact check and the article is filled with those asides that the bots put in there. The asides I refer to are the "are you still with me" and other psuedo-in-your-face punchy nonsense. Half the articles on the internet think I want backfill and history and punchy check-ins rather than the direct information that I used to scan through and obtain in about twenty seconds, but somehow those brand new AI slop sites are the top results on all engines (corruption since they sell services to generate those pages). 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-the-fraudulent https://chemtrails.substack.com/p/vitamin-d-is-rat-poison-th...

egberts1 4mo ago

methylcobalamin B-12 plus Vitamin D3 is the preferred form. Skip the D2 vitamin.

rizsyed1 4mo ago

I think taking a supplement every day is a good idea. I used to suffer from low vitamin D levels constantly until I started taking a daily vitamin D tablet.

ck2 4mo ago

the Vitamin D RDA is too low at 800iu 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

nullbio 4mo ago

Vitamin D is a biomarker of a process that happens in the body that is beneficial for longevity. This biomarker is created in response to receiving sunlight. The synthetic vitamin itself, does little, if anything, for your health. The process of receiving the sunlight is what benefits your health. This applies to a lot of other vitamin supplements as well. 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.

redrove 4mo ago
Do you have any sources for this? Genuinely interested in reading more.
- xolox 4mo ago
  I've recently run into and explored research explaining that natural sunlight stimulates energy production in mitochondria, resulting in an energizing and healing effect completely separate from vitamin D production. I feel bad for posting this without references so here's one reference I could find right now: > This study shows that longer wavelengths in sunlight are transmitted through the body. When these are presented via NIR LEDs in a laboratory-controlled environment at much lower energies, they again have the ability to be transmitted through the body and also are associated with improved visual function independent of ocular exposure. Hence, body penetration by longer wavelengths impacts systemically. Longer wavelengths improve mitochondrial membrane potential and ATP production and improve function in a species conserved pattern that can impact on mobility, visual function and cognition, particularly in ageing. In short lived animals they can extend average life span. > Taken together, these data provide evidence of the importance of the full spectrum of sunlight for human health. They also highlight the potential dangers of the restricted spectra found in white LED lighting in the modern built environment that lacks longer wavelengths and whose output is generally restricted to around 400–650 nm. The absence of longer wavelengths from LED light sources may have implications for public health that should be addressed. Source: https://www.nature.com/articles/s41598-025-09785-3#Sec5 https://www.nature.com/articles/s41598-025-09785-3#Sec5
- 4mo ago

euroderf 4mo ago

Early into the Covid pandemic, there was talk that vitamin D had some protective effect. Did this ever pan out into any kind of recommendation supported by evidence ?

stevedt 4mo ago
https://pmc.ncbi.nlm.nih.gov/articles/PMC8541492/ https://pmc.ncbi.nlm.nih.gov/articles/PMC8541492/

bingoMen 4mo ago

This is a very good, understandable article.