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].
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.
I also suspect that the frequency of outdoor exercise matters even if the total duration of outdoor exercise remains the same. Subjectively, I feel much healthier when doing thirty minutes of outdoor exercise six times a week, than when doing one hour of outdoor exercise three times a week. But then of course, all the causal effects could have been caused by a different factor (say dopamine release) than vitamin D.
Bingo. Obviously being deficient is bad, but the reason supplementation seems unimpressive is this is one of those proxies for healthy lifestyle. Kinda like how grip strength is correlated with longevity but banging out tons of hand gripper sets isn’t going to do much for you health.
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.
Baby aspirin was overdone too. Interestingly, the fish oil hype cycle has a much longer timeline if you consider the popularity of cod liver oil once upon a time.
It's pretty safe to assume all hyped supplements are pointless. Being generally active and eating fruits/vegetables is like 80% of the work for being healthy.
> almost everyone is Vitamin D deficient
This was the red flag that made me realize it was BS early on. If everyone is deficient, then it must not be that important.
The moral of the story here is just to do bloodwork on a regular basis (absolute bare minimum once a year) and respond accordingly. I take some supplements like vitamin D, but I only take what is empirically measurable. If I can't quantitatively measure the outcome, then there is no value and it's a woo woo solution. This isn't always going to be the best advice, but a vast majority of times it will be.
My family runs a blood analysis lab in Belgium for which I wrote some of the statistics gathering software.
The thresholds for 25-OH vitamin D: <20 ng/mL → deficient, 20–30 ng/mL → insufficient.
When I looked at all 1738 blood samples that had their Vitamin D tested between Feb 1, 2020 and Mar 13, 2020 (We were looking into the link between Vitamin D and COVID-19): The median (P50) was 20.1 ng/mL and the average was 22.4 ng/mL. Standard deviation: 11.24 ng/mL Half the samples were deficient, and the next 20% was insufficient.
Coming out of winter in Europe in a country with limited sunshine: most of the population is deficient in Vitamin D.
The Mediterranean diet itself has a lot of health benefits interrelated with the ones claimed about fish oil.
But just as a human experience, the first time I ate cod livers, it was hard to accept. Then I started spreading them on toast for breakfast, and realized that they were quite delicious, but very very much an acquired taste (and I eat almost everything).
As far as Vitamin D, there does seem to be a correlation between deficiency and severe coronavirus disease
[edit] to say, I love chicken and cow liver, but it took awhile to get a taste for fish liver. Pork liver, however, is putrid. I don't think I could eat that again.
Seemingly any decent way to tune in a steady-state supplementation involves multiple iterations of the "get blood test, adjust dosage, repeat" loop
On the other hand, when our body synthesizes Vitamin D itself it seems to regulate that process to prevent overdose. So I've just settled on supplementing in the winter based on my best estimate of the correct dosage, then let my body do its thing in the summer. No issues so far, and supplements have had a major impact on my fatigue/energy/depression levels in the winter
You keep showing up under articles about vitamin D and keep telling that more people have excess than insufficient vitamin D levels without presenting any data whatsoever.
We're among plenty of inside-dwelling nerds here. Do the test. Don't listen to folks like the parent, don't let yourself be discouraged; check your blood level and act on it if necessary, it's fast and cheap. I even had a test done at my home, you can schedule that online these days! You're much more likely to be severely deficient than have it in excess (it's quite hard to get to toxic levels anyway, you'd need to be really irresponsible about it) and once you confirm that, supplementing can help you tremendously with plenty of mental issues you may be experiencing. It won't fix you up, but it can make it possible for you to fix yourself up in the first place. And if the test shows you have adequate levels already - good for you.
(and if you're too depressed to even arrange the test, it may make sense to start supplementing blindly - but don't exceed ~10K IU D3 daily and make sure to stop after 2-3 months tops. Hopefully at that point it'll be easier for you to finally do the test to know whether to continue or not; don't keep taking high doses blindly, toxicity is hard but not impossible to achieve and you really don't want to be suffering from it. You almost certainly won't reach it with 10K IU when starting from deficiency, but it you happened to be on the high side already at the start it could be dangerous when prolonged)
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.
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.
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.
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.
When I did my master's thesis on Vitamin D supplementation the conclusion was that vitamin D testing is wildly inaccurate, and we needed to have studies based on a target level - ideally one based around sub-saharan African community levels.
As for supplementation, sunlight has been estimated at providing up to 20,000IU per day, which I think (not medical advice due to the lack of study), from a mechanistic point of view, suggests an upper limit to daily supplementation.
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.
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.
> loading up a construction site with more materials than are needed shouldn't automatically be assumed to be good
It is almost universally recognized as good to do exactly that. It's better to have oneplanned extra trip to return excess materials (if they can't be used on the next job) than to have multipleunplanned trips when you unexpectedly run out of this or that.
There would still be a ton of goiters if not for iodized salt, basically an obligatory vitamin intake. People had no good iodine source living inland where most anything they catch or grow is not going to have sufficient iodine no matter what it is they were eating.
I'm not sure what the ancestral iodine source might have been. Fishing villages perhaps along the coast? Hard to say how much coast was relatively populated given challenges of shifting shorelines and archaeological efforts. You can still reproduce laden with a goiter however, and that is enough to keep chucking malnourished humans somewhere on earth.
While there is no doubt that excess vitamin intakes are useless or even harmful, the problem is that for most vitamins there is a great uncertainty about which are the optimum daily doses, because the controlled experiments that would be needed to determine those doses would be rightly deemed as unethical.
Therefore, since we only have some weak circumstantial evidence, debates about how much vitamin D is good, and the same about other vitamins, will continue. As long as the uncertainty persists, it is safer to ingest somewhat higher doses of vitamins than those recommended, but not many times higher.
The conclusions of the article were that high amounts of vitamin D have been shown to be correlated with good health outcomes, but the supplementation studies could not reproduce the same outcomes, so it remains mysterious what factor was associated with vitamin D in the studies with positive effects and whether vitamin D itself had any role or its presence was just a coincidence.
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.
> 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.
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.
This is why you're supposed to fatten up in the summer. In nature, mammals fatten up all summer long, and fat soluable vitamins such as D, are stored in your fat.
As animals basically slowly starve over the winter, they consume their fat and also get some vitamin D back. It helps shore up the lack of sun in the winter.
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.
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
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.
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.
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...)
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.
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).
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
88 comments
[ 0.18 ms ] story [ 68.9 ms ] thread[1] https://pubmed.ncbi.nlm.nih.gov/32918215/
[2] https://karger.com/bpu/article-abstract/41/1-3/130/328295/Su...
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.
In this case, about three weeks.
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.
> almost everyone is Vitamin D deficient
This was the red flag that made me realize it was BS early on. If everyone is deficient, then it must not be that important.
The thresholds for 25-OH vitamin D: <20 ng/mL → deficient, 20–30 ng/mL → insufficient.
When I looked at all 1738 blood samples that had their Vitamin D tested between Feb 1, 2020 and Mar 13, 2020 (We were looking into the link between Vitamin D and COVID-19): The median (P50) was 20.1 ng/mL and the average was 22.4 ng/mL. Standard deviation: 11.24 ng/mL Half the samples were deficient, and the next 20% was insufficient.
Coming out of winter in Europe in a country with limited sunshine: most of the population is deficient in Vitamin D.
Histogram: https://files.catbox.moe/p785wx.png
But just as a human experience, the first time I ate cod livers, it was hard to accept. Then I started spreading them on toast for breakfast, and realized that they were quite delicious, but very very much an acquired taste (and I eat almost everything).
As far as Vitamin D, there does seem to be a correlation between deficiency and severe coronavirus disease
https://www.mdpi.com/2075-1729/15/5/733
[edit] to say, I love chicken and cow liver, but it took awhile to get a taste for fish liver. Pork liver, however, is putrid. I don't think I could eat that again.
On the other hand, when our body synthesizes Vitamin D itself it seems to regulate that process to prevent overdose. So I've just settled on supplementing in the winter based on my best estimate of the correct dosage, then let my body do its thing in the summer. No issues so far, and supplements have had a major impact on my fatigue/energy/depression levels in the winter
We're among plenty of inside-dwelling nerds here. Do the test. Don't listen to folks like the parent, don't let yourself be discouraged; check your blood level and act on it if necessary, it's fast and cheap. I even had a test done at my home, you can schedule that online these days! You're much more likely to be severely deficient than have it in excess (it's quite hard to get to toxic levels anyway, you'd need to be really irresponsible about it) and once you confirm that, supplementing can help you tremendously with plenty of mental issues you may be experiencing. It won't fix you up, but it can make it possible for you to fix yourself up in the first place. And if the test shows you have adequate levels already - good for you.
(and if you're too depressed to even arrange the test, it may make sense to start supplementing blindly - but don't exceed ~10K IU D3 daily and make sure to stop after 2-3 months tops. Hopefully at that point it'll be easier for you to finally do the test to know whether to continue or not; don't keep taking high doses blindly, toxicity is hard but not impossible to achieve and you really don't want to be suffering from it. You almost certainly won't reach it with 10K IU when starting from deficiency, but it you happened to be on the high side already at the start it could be dangerous when prolonged)
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.
As for supplementation, sunlight has been estimated at providing up to 20,000IU per day, which I think (not medical advice due to the lack of study), from a mechanistic point of view, suggests an upper limit to daily supplementation.
Note that adequate magnesium is critical for proper vitamin D function, but the article doesn't document it.
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.
It is almost universally recognized as good to do exactly that. It's better to have one planned extra trip to return excess materials (if they can't be used on the next job) than to have multiple unplanned trips when you unexpectedly run out of this or that.
I'm not sure what the ancestral iodine source might have been. Fishing villages perhaps along the coast? Hard to say how much coast was relatively populated given challenges of shifting shorelines and archaeological efforts. You can still reproduce laden with a goiter however, and that is enough to keep chucking malnourished humans somewhere on earth.
Therefore, since we only have some weak circumstantial evidence, debates about how much vitamin D is good, and the same about other vitamins, will continue. As long as the uncertainty persists, it is safer to ingest somewhat higher doses of vitamins than those recommended, but not many times higher.
The conclusions of the article were that high amounts of vitamin D have been shown to be correlated with good health outcomes, but the supplementation studies could not reproduce the same outcomes, so it remains mysterious what factor was associated with vitamin D in the studies with positive effects and whether vitamin D itself had any role or its presence was just a coincidence.
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.
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.
I do take it in the winter, but I'm quite skeptical regarding the panacea hype.
>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.
Can redheads produce Vitamin D in these darker conditions while others cannot do so effectively?
https://www.sciencealert.com/evolution-favored-genes-linked-...
Like... all of Finland? And most of Norway?
Both countries where the answer to "when does the sun rise?" can be "at the end of January".
As animals basically slowly starve over the winter, they consume their fat and also get some vitamin D back. It helps shore up the lack of sun in the winter.
And what were they doing for the other 9 months of the year?
https://pubmed.ncbi.nlm.nih.gov/33549285/
Look at the molecular structure
https://en.wikipedia.org/wiki/Vitamin_D
that's a freakin' steroid with one of the bonds in the rings deleted
https://en.wikipedia.org/wiki/Secosteroid
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.
Why not?
https://pmc.ncbi.nlm.nih.gov/articles/PMC5541280/
And if link is allowed https://sci-hub.ru/https://doi.org/10.1093/ije/9.3.227