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  Aerroon
  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.
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  Aurornis
  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.
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  persedes
  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/
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  rzz3
  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.
• dippogriff
  Vice versa, the exaggeration of vitamin D is mildly worthless. Some need supplements, some don't.
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  PaulHoule
  It's arguable whether Vitamin D is really a vitamin or a hormone, seehttps://pubmed.ncbi.nlm.nih.gov/33549285/Look at the molecular structurehttps://en.wikipedia.org/wiki/Vitamin_Dthat's a freakin' steroid with one of the bonds in the rings deletedhttps://en.wikipedia.org/wiki/Secosteroid
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  amanaplanacanal
  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.
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  cpncrunch
  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/[2] https://karger.com/bpu/article-abstract/41/1-3/130/328295/Su...
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  merb
  > For a while there, many people thought vitamin D was magicalI 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.
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  kazinator
  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=17638508I 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.
• lonelyrock42
  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.
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  legitster
  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.
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  zhivota
  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?
• brandonb
  Another more recent trial (TARGET-D) is showing a 52% reduction in heart attack risk: 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.
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  joehabeebs
  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
• green_wheel
  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.
• skyberrys
  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.
• whycome
  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).
• xutopia
  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.
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  nilirl
  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.
• livingbuddha26
  The veracity of this article depends on who paid you for it, if at all.
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  jmhammond
  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
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  ninalanyon
  > Because physical exams are performed in mobile vans in NHANES, data could not be collected in northern latitudes during the winterWhy not?
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  vondur
  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.
• accidentallfact
  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.)
• rhipitr
  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.
• Johnyjohnson123
  People who say vitamin d isnt important should read about auld rickie...
• d2kx
  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
• anon
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  criddell
  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.
• h4kunamata
  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.
• innocentoldguy
  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.
• fred_is_fred
  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.
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  OutOfHere
  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.
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  atahanacar
  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.
• burnte
  Ugh, more health pontificating from nonexperts. The blog is full of lame "hot takes." Blogspam, IMO.