The Big Vitamin D Mistake [pdf] (2017)
Key topics
A 2017 study is reigniting the debate around Vitamin D supplementation, with some commenters enthusiastically sharing their personal regimens, including doses as high as 5000IU daily. While some express confidence in taking high doses after reading the study's findings, others are wary of overconsumption, pointing out that regulatory bodies have recalled supplements for being too potent. The discussion highlights a disconnect between recommended daily doses and what's available on the market, with some commenters noting that high-dose supplements are easily accessible online. As people weigh in on their own supplementation strategies, a consensus emerges that the officially recommended amounts may be too low.
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I take a 2000IU tablet a few times a week now.
I'm certainly not going to put something from amazon in my body. God only knows what you're actually getting
Also what's an IU. Apparently it's meant to normalize impact across vitamin D species of which there are multiple. Part of me can see the reasoning but it runs contrary to how much of medicine/pharma operates, generally in such form as either mg per time interval or mg/kg per time interval. It would be like taking the whole armada of blood pressure drugs and dictating their doses in mmHg instead of milligrams. If only things were so simple!
I just got more 5000IU at Walmart which was a nice surprise. Normally I take two 2000IU tablets.
Wait, we're talking about birds right?
There's no specific info about any experiment. It just claims a statistics error was recently found in another paper/experiment. It claims fixing the error suggests we should supplement more Vitamin D.
It gestures vaguely at "Diabetes" and "immune health" and "we used to eat fish" to claim that we want/need more blood Vitamin D. It also points to some other actual studies that might have good evidence that we want or need more Vitamin D.
I would doubt anything in this could cause harm. Vitamin D is fat soluble so taking too much can be dangerous, but I don't think the recommended doses here are close to that dosage.
This paper aims for slightly more than 100nmol/l Vitamin D marker in blood, while other NIH papers claim >375nmol/l is getting into Vitamin D toxicity territory.
>https://pmc.ncbi.nlm.nih.gov/articles/PMC6158375/
NIH previously claimed a serum level of less than 72nmol/l is a health problem, so this paper is bumping that up slightly.
My understanding is that large scale tests of Vitamin D supplementation don't ever seem to turn out as great as all these papers would imply. Maybe their experiments had too low a dose.
My own supplementation has done jack and shit. Maybe I needed a higher dose.
I still hold skepticism that all of humanity needs a supplement, as that's just a sales pitch from a company at that point, but the "Everyone really does need a shitload of Vitamin D supplement" hypothesis at least has a mechanism that makes sense.
Also, remember - don't take D on its own. Always with magnesium, or you get harmed by it, for all that it also does you good. Body is not built for raw D.
Also also remember, D2 is a vitamin, D3 is a hormone.
This is the link to the article in the PubMed database: https://pubmed.ncbi.nlm.nih.gov/28768407/
You can click on the DOI link to go to the article hosted by the journal.
As a naive person, what's the consequence of this?
“D2 is a vitamin, D3 is a hormone.”
This is biochemically muddled:
Vitamin D2 (ergocalciferol):
Plant/fungal-derived (e.g., UV-exposed mushrooms, fortified foods).
Vitamin D3 (cholecalciferol):
Produced in human and animal skin from 7-dehydrocholesterol via UV-B. Also used as a common supplement form.
Both D2 and D3 are inactive precursors. They’re hydroxylated to 25-OH-D, then to 1,25-(OH)₂-D (calcitriol), which is the actual hormone that binds the vitamin D receptor.
So:
D2 and D3 are best described as prohormones (and traditionally called “vitamins”).
The hormone is calcitriol, not “D3 itself” as found in supplements.
Functionally, both D2 and D3 end up as the same type of hormone (1,25-dihydroxyvitamin D), though their pharmacokinetics differ.
The real difference between D2 and D3:
Both raise 25-OH-D, but D3 is generally more effective and longer-lasting than D2 at comparable doses. Prevention
So the line should NOT be taken literally. A more correct framing:
“Vitamin D (whether D2 or D3) is technically a prohormone; its active metabolite behaves like a hormone. D3 is the human/animal form and is more potent than D2 at raising blood levels.”
I think it's important to clarify understandings for non-scientific/med community each time these types of technical discussions occur.
So do your research or something.
I have no idea what to follow at this point
I would not take that much consistently unless you're in the arctic circle and its winter
Some previous discussions:
4 months ago, flagged: https://news.ycombinator.com/item?id=44705486
2020: https://news.ycombinator.com/item?id=24768721
2017: https://news.ycombinator.com/item?id=15867918
We're learning more about what Vitamin D does
https://news.ycombinator.com/item?id=46088998
Vitamin D reduces incidence and duration of colds in those with low levels
https://news.ycombinator.com/item?id=45732670
> However, the evidence for the health benefits of vitamin D supplementation in individuals who are already vitamin D sufficient is unproven.
andvitamin D is liposoluble so overdose is a risk. So I strongly recomend to ask a real medical doctor.