Heart Health
What the latest evidence shows — and what it doesn't
If you've been told you have calcium deposits in your arteries, you may have come across claims that Vitamin K2 can reverse the damage. The short answer is: it cannot undo what's already there. Once calcium hardens inside an artery wall, those deposits are permanent — no supplement can dissolve them. But growing clinical evidence suggests that Vitamin K2 may help slow down the rate at which new calcium deposits form.
What actually happens inside your arteries?
When calcium hardens inside an artery wall — a condition called coronary artery calcification — it sets in place, much like concrete once it has cured. It cannot simply dissolve back into the bloodstream. What Vitamin K2 may be able to do is act as a brake, slowing the rate at which new deposits form in your blood vessels.
How does Vitamin K2 work in the body?
Your body produces a protein called matrix Gla protein (MGP). Think of it as a traffic warden for calcium: its job is to stop calcium from settling in the wrong places — such as the walls of your arteries.
For MGP to do that job properly, it needs to be switched on. The switch is Vitamin K2.
When K2 levels are adequate, MGP is activated. It intercepts calcium circulating in the bloodstream and redirects it away from your artery walls, towards your bones and teeth, where it is genuinely needed (Hariri et al., 2021). When K2 levels are low, MGP remains dormant, leaving calcium unguided. Research has closely linked this inactive state to stiffer arteries and faster progression of coronary artery disease.
What does the research actually show?
Cardiologists are increasingly interested in Vitamin K2 — particularly when paired with Vitamin D — as a possible way of slowing coronary artery calcium progression. One of the most significant recent studies is the 2023 AVADEC trial: a double-blinded randomised controlled trial (the gold standard of medical evidence). Participants with significant existing calcium deposits were given a daily combination of Vitamin K2 (720 micrograms) and Vitamin D for two years.
Key Finding
Overall, the trial found no statistically significant reduction in calcium progression across the whole group. However, in a pre-specified subgroup of men carrying the heaviest calcium burden (scores above 400), supplementation significantly slowed the rate of further build-up compared with those taking a dummy pill.
A trend toward less soft, unstable plaque was also observed in the supplement group, though this did not reach statistical significance. Notably, serious cardiovascular events — including heart attacks and deaths — occurred in significantly fewer participants who received the supplements (1.9%) than those who did not (6.7%), a finding the researchers describe as exploratory and in need of further study (Hasific et al., 2023).
What the trial did not show was any reversal of existing calcification, or a benefit for those with lower calcium scores. The researchers have since launched a follow-up trial (DANCODE) specifically to confirm the high-burden subgroup findings.
Where does Vitamin K2 come from?
Vitamin K2 is very different from Vitamin K1, found in leafy greens such as spinach and kale. Eating more salad will not raise your K2 levels. K2 is primarily produced by bacteria and is found in a much narrower range of foods:
| Food Source | K2 Type | Notes |
|---|---|---|
| Natto (fermented soybeans) | MK-7 | Highest concentration of any food; strong taste and texture |
| Fermented cheeses (Gouda, Edam) | MK-7 | Good amounts; more widely available in the UK |
| Dark chicken meat (thighs, legs) | MK-4 | Among the best meat sources |
| Beef liver | MK-4 | Rich source; acquired taste |
| Egg yolks | MK-4 | Modest amounts |
| High-fat dairy (butter, hard cheeses) | MK-4 | Modest amounts; varies by product |
The challenge is that the therapeutic doses used in clinical trials — 720 micrograms of K2 (MK-7 form) per day — are extremely difficult to reach through diet alone, particularly on a typical Western diet. For this reason, cardiologists researching this area generally favour supplementation over relying on food sources alone (Hariri et al., 2021).
⚠ Important
Before starting a high-dose Vitamin K2 supplement, speak to your GP or cardiologist first. K2 can interact with blood-thinning medications such as warfarin, and the right approach will depend on your individual medical history and any other medicines you take.
The bottom line
Vitamin K2 is not a cure for coronary artery disease, and it will not dissolve existing calcium deposits. However, the clinical evidence that it may slow further progression — particularly for those already carrying a heavy calcium burden — is growing stronger. A follow-up trial is already under way to build on these findings.
As always, any decision about supplementation at therapeutic doses should be made in partnership with a healthcare professional who knows your full medical picture.
References
Hariri, E. et al. (2021) 'Vitamin K2 — a neglected player in cardiovascular health: a narrative review', Open Heart, 8(2), p. e001715. Available at: https://openheart.bmj.com/content/8/2/e001715 (Accessed: 5 June 2026).
Hasific, S. et al. (2023) 'Effects of Vitamin K2 and D Supplementation on Coronary Artery Disease in Men: A RCT', JACC: Advances, 2(9), p. 100643. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC11198368/ (Accessed: 5 June 2026).
IMPORTANT MEDICAL DISCLAIMER
The content provided in this blog post is for educational and informational purposes only and does not constitute professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. Always consult with a qualified healthcare professional or your GP before starting any new supplement regimen, particularly if you manage pre-existing conditions or take prescription medication.
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