Scientifically reviewed by: Dr. Gary Gonzalez, MD, in May 2025. Written by: Lina Buchanan. Credit: Life Extension

Witamin K has long been known to support bone health by helping to keep calcium in bones.1

It also helps keep calcium out of blood vessels, where it can lead to calcified plaque buildup that contributes to coronary heart disease.1,2

Observational studies show that a higher intake of vitamin K is associated with lower risk of heart disease and atherosclerosis.3-7 In one observational study, those with the highest vitamin K intake had a 57% lower risk of cardiovascular mortality over 10 years.8

In clinical studies, vitamin K intake reduced vascular calcification9,10 and stiffness11-13 and slowed or prevented the progression of blood vessel disease.10,12,14

Studies suggest that both forms of vitamin K (K1 and K2) play a role in health outcomes, influencing everything from bone health2 to cardiovascular risk2,4 and all-cause mortality.15

What is Vitamin K?

Vitamin K occurs in two forms:16

• Vitamin K1, which is primarily found in green, leafy vegetables, and

• Vitamin K2, which is found in small amounts in some animal products (like egg yolks and chicken) and in higher amounts in natto, fermented soybeans.

While both forms are beneficial, vitamin K2 has better bioavailability and maintains levels in the body for longer.17,18

Low levels of vitamin K are commonly seen in older individuals.19,20 One study estimated that suboptimal levels are found in an astonishing 97% of older adults.21

Vitamin K activates several vitamin K-dependent proteins, including ones required for normal clotting of blood after an injury.22

Other vitamin K-dependent proteins include osteocalcin, matrix Gla protein, and Gas6.23 These proteins regulate calcification through different mechanisms, thereby reducing risk of harmful calcification in blood vessels2,24 and in soft tissues.2,23,25

Vitamin K and Cardiovascular Disease

The accumulation of calcium in the arteries and heart valves is a major driver of heart and blood vessel disease. This calcification causes the tissues to stiffen and contributes to atherosclerosis, which narrows the blood vessels and increases risk of cardiovascular disease, including stroke.26

If this happens in the coronary arteries, an ischemic heart attack can result. In the arteries supplying the brain, stroke risk increases.27

Vitamin K2 improves bone health and protects against cardiovascular risks.

It activates the calcium-binding protein osteocalcin in bone to maintain bone strength28 and matrix Gla protein in soft tissues to reduce calcium deposition in areas outside the skeleton, such as arterial walls.29,30 Matrix Gla protein and Gas6 are present in many tissues, including arterial walls, where their active form helps inhibit arterial calcification and may also stabilize existing plaques.2

Without enough vitamin K present, these proteins cannot be activated in their active form. The result is calcium loss in bones and an increase in calcium in arteries, accelerating atherosclerosis and increasing the risk of cardiovascular disease.28

In preclinical models, lack of matrix Gla protein activity in mice causes the animals to die prematurely due to massive arterial calcification and rupture of arteries.31,32

What Human Studies Show

Human observational studies consistently find that low vitamin K intake is associated with increased risk of:

• Coronary heart disease,3,4,6

• Hospitalization for atherosclerotic cardiovascular disease,3,5,6

• Cardiovascular-related death,7,33,34 and

• Death from any cause.15,34,35

In one study of almost 5,000 adults aged 55 and older followed for up to 10 years, those with the highest intake of vitamin K2 had a 57% lower risk of cardiovascular mortality and a 26% lower risk of death from any cause compared to those with the lowest intake.8

In another study of over 7,200 subjects followed for a median of 4.8 years, the risk of all-cause mortality was 45% lower in those with the highest vitamin K intake compared to those who decreased or did not change their intake.35

Results from other observational studies are equally impressive:

• In a study of over 16,000 women followed for an average of eight years, each additional 10 mcg of vitamin K2 intake daily was associated with a 9% reduction in risk for coronary heart disease.36

• In a study of more than 36,000 participants followed for an average of 12 years, those with the highest intake of vitamin K2 had a 41% lower risk of peripheral artery disease among individuals with high blood pressure and a 44% lower risk among those with diabetes, compared to participants with the lowest intake.37

• In a study involving more than 53,000 participants followed for about 20 years, higher intake of vitamin K1 was associated with a 21% lower risk and the highest intake of vitamin K2 with a 14% reduced risk of hospitalization for atherosclerotic cardiovascular disease compared to those with the lowest vitamin K intake.3

• In a study of over 55,000 subjects followed for up to 21.5 years, the highest intake of vitamin K1 was associated with a significantly lower risk of aortic valve stenosis, as compared to the lowest intake. Aortic valve stenosis is a potentially life-threatening condition that reduces blood flow from the heart to the rest of the body.38

Reducing or preventing calcification in the arteries can have dramatic benefits.

Dozens of clinical studies show that vitamin K intake reduces vascular calcification and the risk of cardiovascular disease.9,10,14

For example, in a recent study of post-menopausal women, taking 180 mcg of vitamin K2 (as MK-7) daily for one year, decreased vascular stiffness, which is closely associated with the progression of cardiovascular disease.13

What You Need To Know

Cardiovascular Benefits of Vitamin K

• Vitamin K is required for the activation of proteins that keep calcium in bones and prevent abnormal calcification in other tissues.

• In the heart and blood vessels, calcification is one of the major drivers of atherosclerosis, coronary heart disease, and heart valve disease.

• Large observational studies show an association between higher vitamin K intake and lower risk of heart and blood vessel disease, cardiovascular-related death, and death from any cause.

• In clinical trials, vitamin K intake reduced vascular calcification and risk of cardiovascular disease.

Chronic kidney hemodialysis patients are at an elevated risk of vascular calcification and cardiovascular disease. In a clinical study, 73% of diabetic hemodialysis patients who took a placebo for 24 weeks had a worsening of arterial disease, compared to only 21% of those who took 375 mcg of vitamin K2 (as MK-7) daily.12

Many trials of vitamin K are ongoing, but evidence shows that it may help reduce risk of calcification and progression of heart disease.

Summary

Calcification in blood vessels is a major component of atherosclerosis, which drives heart disease.

Vitamin K helps keep calcium in bones and out of arteries.

Observational studies show a correlation between higher vitamin K intake and lower risk of vascular calcification and stiffness, cardiovascular-related mortality, and death from any cause.

Clinical trials also show that vitamin K intake improves vascular health and reduces the risk of cardiovascular disease.

Can Taking Vitamin K Increase Clotting Risk?

Because vitamin K promotes healthy clotting, some people worry that taking it orally could increase the risk of abnormal blood clots.

This is not the case. Studies of long-term, high-dose vitamin K supplementation have shown that oral intake is safe and does not increase the risk of abnormal clot formation. Only those on the drug warfarin (Coumadin®), because it works as a vitamin K antagonist, should be cautious about their vitamin K intake.

References

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3. Bellinge JW, Dalgaard F, Murray K, et al. Vitamin K Intake and Atherosclerotic Cardiovascular Disease in the Danish Diet Cancer and Health Study. J Am Heart Assoc. 2021 Aug 17;10(16):e020551.

4. Haugsgjerd TR, Egeland GM, Nygard OK, et al. Association of dietary vitamin K and risk of coronary heart disease in middle-age adults: the Hordaland Health Study Cohort. BMJ Open. 2020 May 21;10(5):e035953.

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