- 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.
- It's arguable whether Vitamin D is really a vitamin or a hormone, see
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
- It's pretty 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" has just stuck around since it was named in 1922.
- 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.
- K2 is also known to prevent problems with calcium build up which can happen if Vitamin D is dosed too high. I personally would never take Viramin D without K2 alongside it.
- TARGET-D is an in-progress study that supplements vitamin D based on blood levels (your idea).
- Were you taking hard tablets? And were you taking them with a fatty meal?
Those are both very important. I take a Vitamin D + K2 softgel with a meal that has some fat in it.
- What I found was that I had to dissolve vit D under the tongue, not immediately swallow it.
- > 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.
- 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.
- 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.
- This is how I found my 10k IU of vitamin D a day, based on modern recommendations for indoor workers, that I modulate based on how much I'm outdoors, was perfectly on the mark!
- Also an indoor worker. 10K IU daily would have put me far into hypervitaminosis D range.
Make sure you test after a very long time, such as a year of steady supplementation. A lot of the excess Vitamin D cases were taking less than 10K IU daily.
- This is the amount I shoot for in the winter - I live in New England - it's made a huge difference in my life. I'm totally open to it being placebo though and I don't care. I don't supplement with it during the summer.
- Yes, and to be concrete, you can do so at economical prices at https://requestatest.com (it's a lifesaver in many occasions, I've used it 4 times with great success).
- My PCP uses Quest Diagnostics and a vitamin d test is, I think, about $50. No fasting needed for it, nor prescription.
- > 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.
- [dead]
- > 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.
- 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.
- Most vitamins are a cofactor for enzymes like
https://en.wikipedia.org/wiki/Thiamine#Biological_functions
Vitamin D is not but rather it regulates calcium and phosphorous metabolism.
- Vitamin D deficiency entered the chat. It's a relatively common issue in many countries.
- 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.
- 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.
- 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.
- My life changed after I got tested for vit D and started talking supplements. I was severely deficient. I am now sufficient and everything changed for me.
- In December by chance I put a pack of Vitamin D into my shopping basket. I did not think much, thought to take 1000IE but then decided that for the first week I take 3000 to catch up. Muscle pain went and control over eating improved. I did not expect any changes based on past experience with 1000 but this time I could not ignore it (age can play a role) and I stayed on 3000. Tests a month later showed I was just not deficient any-more. I continued on the regime and started having improvements in long running skin issues to the extent my dentist noticed. It may not be a miracle drug but one should not underestimate cumulative impact individual factors, age and lifestyle changes (less sun) that may change levels and demand.
- That doesn't undermine OP's point. Being deficient is unhealthy. But that doesn't mean an overabundance makes you healthier.
- What exactly changed?
- Keep in mind vitamin D is really, among other things, an immune signaling molecule.
So, we know the mechanism, and it's quite plausible that supplementation works.
In other words, as an skeptic, I don't think it's just an epidemiological correlation.
- Ding ding ding.
People who are drawing blood and trying to find some correlation between vitamin presence and health at this point are just practicing divination. The fact that it can be published in a scientific journal without any sort of RCT to back it up is palpably unscientific.
The customers of these studies are the supplement companies looking for another product to sell.
- Maybe this is true if you’re only considering white people. Brown people can spend a lot of time outdoors and still be deficient, especially if their ancestry is from much a much sunnier region or lifestyle than the one they’re currently living in.
- It depends on one’s whereabouts and kind of exercise. Exercising in a gym or outside with all your skin covered won’t make much vitamin D.
- But then why do we see improvements in people that get vitamin D + K2 supplements and not exercise?
- As the article mentions, we pretty much don't see improvements with supplementation.
- 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.
- From the article:
> the balance of evidence tips pretty clearly in the direction that people with low-ish levels would be wise to supplement
- Yeah, I wish the article had brought Vitamin K2 into the mix since that seems trendy to pair with your D3 these days.
- 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...
- Sunlight would likely get you all the "red light therapy" effects too.
- People who say vitamin d isnt important should read about auld rickie...
- 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.
- examine.com
- 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.
- 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.
- 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.
- 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.
- 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.
78 points by surprisetalk 3 hours ago | 47 comments