Episode 135 – Do You Need To Supplement Vitamin K2 Alongside Vitamin D?

Key Topics Covered

Vitamin K2 and Vitamin D supplement.

Very often, whenever Vitamin D gets brought up through our social media posts, so do comments about the inclusion of Vitamin K2. This has prompted this episode and we are going to explore the relationship between the two.

Theory Behind It

  • Taking vitamin D can improve our absorption of calcium. It also can cause our body to produce more vitamin K2-dependent proteins.
  • Vitamin K2 is responsible for depositing calcium in the “right places” in the body.
  • Put simply, if you were to supplement 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 the proposed theory. 

Taking Vitamin D Independently

Vitamin D supplement

  • If that theory were to be true, this should be easy to test. 
  • We could jump straight to research looking at Vitamin D supplementation in isolation and CVD issues and there would be a direct link, but this is not what we see in the research.
  • One study with over 20,000 participants found that taking the equivalent of 2,000IU of vitamin D per day over 5 years had a LOWER rate of CVD issues.
  • I wouldn’t read into that too much because a 2021 review looking at all the research found that vitamin D supplementation neither increased nor decreased the risk of CVD outcomes. But regardless that in itself says something.
  • In the research, there is no consistent link between vitamin D and increased CVD risk.
  • Alternatively, Vitamin D deficiency has been associated with increased cardiovascular disease risk factors.

Vitamin K & Heart Health

  • Looking at vitamin K in isolation makes this topic more interesting.
  • Vitamin K supplementation appears to reduce vascular calcification.
  • This is difficult to measure, but sub-clinical deficiencies of vitamin K appear common, making supplementation more relevant.
  • An 11-year study on dietary vitamin K and coronary heart disease found reduced risk with higher intake.
  • Overall though, there’s not a lot of research on the topic.

Vitamin K & Vitamin D for Bone Health 

  • There appears to be some synergy between vitamin K and vitamin D.
  • Supplementing them together improves bone mineral density more than supplementing them individually does.
  • From that perspective alone, it may be worth doing, especially if there is a sub-optimal intake of vitamin D at the baseline.
  • A group called ‘Grassroots Health’ have also put out data showing that vitamin K2 can also make vitamin D supplementation more effective at increasing blood levels of vitamin D.
  • This means that lower supplement dosages are needed.

Vitamin D & Vitamin K for Heart Health

Heart in chest

  • A 3-year randomized controlled trial involving 400IU vitamin D and 600mg calcium per day with or without 500μg vitamin K found less coronary artery progression in the group that had vitamin K.
  • This study is often referenced in this space.
  • This is a summary of the overall research:
  1. Two trials directly looking at vitamin D versus vitamin D and K found that when vitamin K was added, there was a reduction in vascular calcification progression and cardiovascular risk factors.
  2. Another study looking at vitamin D and calcium together found a 24% increased risk of myocardial infarction. However, high dose calcium supplementation seems to have a link with cardiovascular disease risk.

Practical Takeaway

  • Vitamin D supplementation by itself has not been linked with an increased risk of cardiovascular disease.
  • Vitamin K by itself has been shown to reduce the build-up of calcium in the arteries. And supplementation has consistently reduced risk.
  • Putting vitamin D and vitamin K together might reduce the risk of cardiovascular disease – but that could be largely unrelated to the vitamin D component.


Vitamin D and Vitamin K2 Supplements


  • If supplemental vitamin D in appropriate doses caused this issue, would naturally having good levels of vitamin D not cause these same issues?
  • If we are so concerned about supplementing these two together, should we be concerned about people who naturally already have good levels, but are not supplementing vitamin K2?
  • We see research showing high-dose calcium supplementation leading to an increased risk of cardiovascular disease for the reasons people are concerned about vitamin D.
  • However, we do not see these issues with appropriately dosed vitamin D in isolation. Is this more of a calcium issue and less of a vitamin D issue?


  • At a population level, either supplementing vitamin K2 or increasing dietary intake likely does help. And these benefits likely occur with or without vitamin D.
  • Vitamin D has benefits. Vitamin K has benefits. Supplementing them together likely is synergistic in many ways, including improving bone mineral density.

Although we do not have enough research to say this conclusively, it appears safe to supplement vitamin D by itself in appropriate dosages.

Vitamin K2 supplementation might help reduce the risk of cardiovascular disease, but that risk appears to not have been increased by vitamin D supplementation anyway.

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