Leah:
Hello and welcome to the Ideal Nutrition Podcast. I am Leah Higl and I’m here with my co -host Aidan Muir and today we’re going to be answering the question, do you need to supplement vitamin K2 alongside vitamin D?
Aidan:
So the thing that’s prompted this for me is that starting like a few years ago, every time I posted about vitamin D on Instagram or any other platform really, there would often be at least one person who would make the comment, something along the lines of, make sure you take it with vitamin K2 though, as well. And I had always found that a little bit interesting because every time I’d like started going down that rabbit hole, I was kind of like, well, we clearly see health benefits from vitamin D alone and performance benefits as well. Is this really an urgent thing?
It doesn’t take too long to find this, but going deeper down the rabbit hole, you can start to see the theory as to why a lot of people are pretty passionate about that. And there’ll be, we’re going to talk about a lot of this because there is some merit to it as well and there’s nuance as well. So starting with the theory behind it before we talk about pros, cons, anything like that. Taking vitamin D, like the theory is, that taking vitamin D can improve our absorption of calcium. It can also cause our body to produce more vitamin K2 dependent proteins. The next step is that vitamin K2 is arguably responsible for depositing calcium in the quote on quote right places in the body. That stuff is all true.
The next part of the theory is basically if you were to suffer with vitamin D without sufficient vitamin K2, you would potentially be depositing more calcium in your arteries or other soft tissue. This would lead to an increased risk of cardiovascular disease. But we need to look at this concept beyond just that proposed theory because there’s a lot of moving parts in here.
Leah:
Yeah, definitely a lot to cover from a lot of different perspectives. But I think let’s boil it down to just like vitamin D by itself first. So stating the obvious, if that theory were to be true, the one you’ve just gone through, then it would be a very easy thing to test in that it would be very clear in the research, particularly looking at vitamin D supplementation. So we can literally jump straight into looking at the research around vitamin D supplementation when taken in isolation and see if there is a link between that and cardiovascular disease issues.
Theoretically it should increase cardiovascular disease based on that logic. Yeah, based on that logic we should see this link in research. What’s interesting is that we don’t really see this happen in research. Looking at some specific research, one study with over 20,000 participants found that taking an equivalent of 2,000 international units of vitamin D per day over a five-year period actually had a lower rate of cardiovascular disease issues. We wouldn’t read too much into that because when you like kind of scale back and look at the evidence and research as a whole, there doesn’t seem to be like a very strong link between vitamin D supplementation and lower rates of CBD issues. Its a bit of a mixed bag of results. But what is consistent is there’s no specific research showing that vitamin D supplementation in isolation increases cardiovascular disease risk.
Aidan:
So that’s a good starting point and that’s why it actually took me a while to go down the rabbit hole fully because it’s like, it doesn’t seem to be like, doesn’t seem to be an issue. It wasn’t probably until about a year or a year and a half ago that like I went full in on this but it just kept getting repeated. So was like, I think it’s time to go down properly on this. Yeah. The next part of it. So we looked at vitamin D by itself.
The next obvious point is let’s look at vitamin K by itself, looking at heart health specifically. So research on vitamin K supplementation by itself shows that it appears to reduce vascular calcification by itself. So theoretically, it’s putting calcium in the right spots, like it is doing that part of the job. It is difficult to measure. I don’t have a strong opinion on this. Do not read too much into this, but there is a bit of a consensus that subclinical deficiency of vitamin K appear to be common too which makes supplementation more relevant, particularly at a population level when you think of it like that, being like, okay, that probably explains why when you have vitamin K by itself, it seems to improve these situations.
The thing is we don’t really have that much research, so it’s hard to make a very strong take on this position, but there was an 11 year study looking at dietary vitamin K intake, and they found that coronary heart disease had reduced risk with higher intake of vitamin K. So bit of a summary so far, vitamin D by itself doesn’t seem to increase risk of cardiovascular disease. Vitamin K by itself seems to, based on what we know, knowing that there’s a few gaps, but seems to reduce the risk a bit.
Leah:
Now that we’ve looked at vitamin D and vitamin K separately, we can talk about a little bit of those both in combination specifically for bone health. So there does appear to be some synergy between vitamin K and vitamin D. So supplementing them together does seem to improve bone mineral density more than supplementing one individually does. So from that perspective alone, just from a bone health point of view, it may be worth doing. Especially if there’s already a sub optimal intake of either one of those like at baseline, it’s probably going to be worth doing at that point.
A group called Grassroots Health had some interesting data that showed that vitamin K2 can also make vitamin D supplementation more effective at increasing blood levels of vitamin D, meaning that you potentially need less vitamin D supplementation or intake for it to be, like, had the same beneficial effect. So that’s kind of like a secondary point at which that would make vitamin K or K2 beneficial to supplement alongside vitamin D.
Aidan:
Yeah, I think that’s interesting. And it’s one of the things that I think is huge, if true, being like that’s all the data we’ve got looking at that and looks incredibly positive. I’d love to see more just to be like, we know this for sure. And like, there’s that link with the whole like, need for more vitamin K2 dependent proteins, etc. Like kind of makes sense a bit. Yeah. Interesting that you can clearly see a bit of synergy there as well.
So looking at another area of potential synergy, maybe we’ve got vitamin D and vitamin K2 together looking at it from a heart health perspective. there’s a three year randomised control trial. So like gold standard of science really in this case without looking at meta-analysis data of randomised control trials. This three -year randomised control trial looking at 400 international units of vitamin D and 600 milligrams of calcium per day with or without 500 micrograms of vitamin K found less coronary artery progression in the group that had vitamin K. This study has referenced heaps in this space, but we want to take this a step further because there’s more than just vitamin D in there, there’s also calcium in there too.
We had also said that vitamin K by itself seemed to lead to a decrease in this coronary artery type of progression of the vascular calcification. We’ve referenced quite a few studies in the show notes that if anyone wants to fact check any of the things I’m about to say, you can just go and check there. But a brief summary.
Two trials directly looking at vitamin D versus vitamin D and vitamin K found that when vitamin K was added, there was a reduction in vascular calcification progression and cardiovascular risk factors, which based on everything we’ve said, makes sense. Like we kind of see that with or without vitamin D most likely. Another study found that vitamin D and calcium together without vitamin K found a 24 % increased risk of myocardial infarctions, but high dose calcium supplementation by itself has a bit of a link with cardiovascular disease.
I don’t really want to put that out there as a bit of a hot take, but it’s like we have clear research that vitamin D by itself doesn’t seem to have a link. But the process that people are concerned about is the calcium ending up in the wrong spots, etc. And there is a little bit of a link between high dose calcium supplementation and cardiovascular disease, which makes this topic a bit nuanced, so to speak.
Leah:
Yeah, for sure. And I think like in terms of my understanding of all this prior to looking into it further really was about the calcium component more so than the vitamin D component. So looking further into this was really interesting. And putting that together in almost kind of a bit of a summary, but we’ll get to that.
Vitamin D supplementation by itself has not been linked with increased risk of cardiovascular disease. On the flip side, vitamin K by itself has been shown to reduce the buildup of calcium in the arteries and supplementation with vitamin K has consistently reduced the risk of cardiovascular disease. So putting vitamin D and vitamin K together might overall reduce the risk of cardiovascular disease, but I would place my bets on this being largely unrelated to that vitamin D component.
Aidan:
Yeah, that’s a really good summary. I’m gonna take a moment here to expand on everything with some thoughts I had going into this. I was like, I don’t wanna put this at the start, let’s put it at the end. One of the most interesting things about being like, if people are just saying, every time you take vitamin D, you need to take vitamin K too. If that was to be the case, let’s highlight some other laws to a degree in that logic. The first one, what if you just had really good levels of vitamin D?
Leah:
Sure, like you’re just naturally getting that through sun exposure and dietary intake.
Aidan:
Is it different to supplement vitamin D to get to good levels versus just having it naturally? Like if you just naturally had very good levels, that would mean you’re absorbing calcium quite well based on that same kind of logic. Does that mean you would run into that issue if that were to be an issue? That’s the first thing to think about, being like, if just getting more sun just caused this issue?
If we’re so concerned about that, should we not be concerned about people who have good levels not supplementing vitamin K2 just in general? Particularly when you line that up with the subclinical population wide type of deficiency as well. Touched it already, but we see research showing that high-dose calcium supplementation leads to an increased risk of cardiovascular disease. We don’t say that with vitamin D. Is this more of a calcium issue than a vitamin D issue? Does that mean we should take vitamin K2 alongside calcium?
I’m not going to say I’ve tried looking super hard, but I don’t really see people saying that very much. It’s food for thought in a way, just being like it’s another area worth exploring. We don’t really have research looking at that either. So if anyone was saying a lot of stuff in that space, like we don’t have a lot of research to go on anyway.
Leah:
There is a lot of supplements though with all three together.
Aidan:
We see a lot with all three. It’s just like, yeah. And we also see a lot of supplements though, just vitamin D and vitamin K2 as well. If you’re wondering why I keep interchangeably going between vitamin D, sorry, vitamin K and vitamin K2, it’s just vitamin K2 is like a form of vitamin K that we naturally do find through certain foods, often like organ type foods, like it’s a little bit different from like what normal dietary sources of vitamin K would be. But I’m just using them interchangeably because typically supplements are vitamin K2 is what most of this research is done on.
Brief summary though, vitamin D has benefits, vitamin K has benefits. Supplementing them together is likely synergistic in many ways, particularly when it comes to improving bone marrow density, which is one of the goals a lot of people have. But coming back to the answer to this question, do we need to supplement vitamin K too alongside vitamin D? It appears very safe to supplement vitamin D by itself in appropriate dosages.
Vitamin K2 supplementation might reduce the risk of cardiovascular disease, but the risk does not appear to have been increased by vitamin D supplementation to start off with anyway.
Leah:
That’s a great summary, you did a great job. This has been episode 135 of the Ideal Nutrition Podcast. If you haven’t yet left a rating or a view, it would be greatly appreciated for you to do so. Otherwise, thanks for tuning in.