Vitamin K2 Decreases Heart Disease and Stroke Risk

Cardiovascular (heart and blood vessel) disease is the most common cause of death in the US with over 801,000 people dying every year. Over 1,370 people die every day because plaques containing calcium build up in their blood vessels. This restricts the flow of life-giving blood to their hearts and their brains and may lead to a heart attack or stroke.


But how does the calcium get there? Is it from the calcium and vitamin D supplements you may be taking? It could be. Is there a missing nutrient that can prevent calcium deposits in the arteries and thus arterial plaque build-up? Yes there is--vitamin K2. 

In 2010, scientists examined 12,000 people over the age of 40 and found that, by taking 1,000mg of calcium a day, they had a 30% increase incidence of heart attacks.

Another 2011 research trial of 36,282 post menopausal women compared those taking 1,000mg of calcium and 400IU of vitamin D per day with those taking a placebo and found a 21% increased risk of a heart attack and a 20% increased risk of stroke.

A third study in 2012 of 23,980 subjects found a 239% increased risk of a heart attack with those taking calcium supplements. Interestingly, there was no increase in people that got their calcium from diet alone.

And lastly, a 2013 paper looked at 61,433 women that were followed for 19 years confirmed these findings. It showed that women who had a high dietary intake of calcium (>1400mg per day) and took calcium supplements were 2.57 times more like to die from all causes including cardiovascular disease but not from stroke.  

Vitamin K2 can prevent heart disease and stroke. 

Here is how it works. Vitamin D is a hormone. It changes the gene expression in your intestinal cells and allows them to bind more calcium and pull it in to the body. When you have low levels of vitamin D, you get around 10-15% absorption of calcium. When you have higher levels of vitamin D, you get between 30-40% absorption of calcium. If you are taking 1000-1500mg of calcium and 3,000-5,000 IU of vitamin D every day, you are getting a lot of calcium circulating in your body. This is where K2 comes in. K2 is used by the body to make a series of proteins that will protect the body from excess calcium. Two such proteins are called osteocalcin and matrix GLA protein or MGP. Osteocalcin, after being primed by vitamin K2, will bind to calcium and put it in the bones. Matrix GLA Protein (MGP), after being primed by K2, will sweep through the soft tissues of the body (think blood vessels) and clean up any calcium that deposited itself there. In essence, these two proteins keep calcium out of the vessels and put it in the bones. 

When we do not have enough vitamin K2 around, calcium can accumulate in the vessels that lead to the heart and the brain, thus increasing the risk of having a heart attack or stroke.

On the opposite end of the spectrum, human studies are demonstrating the ability of increased levels of vitamin K2 to decrease arterial calcification and cardiovascular deaths.

In 2004, 4,807 people were evaluated for vitamin K intake. People eating the foods with the highest K2 had up to a 52% decrease in arterial calcification. They also had up to a 57% decrease in death from heart disease.  The foods most associated with the decreased rates were meats, eggs, sauerkraut, fish, cheese, and other dairy products. Note: pastured/grass fed dairy product have higher levels. 

Two scientific trials confirmed these findings with one showing a 20% decrease in coronary artery calcification with higher vitamin K2 intake and the second approximated a 9% decrease in coronary heart disease for every 10mcg of vitamin K2 that was ingested per day. 

Supplementation with K2 appears to be effective as well. When 180mcg of MK7 was taken every day for 3 years by healthy postmenopausal women, it improved arterial stiffness. 

There are some upcoming trials where researchers are supplementing vitamin K2 in the form of MK7 and measuring multiple markers of cardiovascular disease. The authors of the VitaK-CAC trial made this optimistic statement. “We hypothesize that treatment with MK7 will slow down or arrest the progression of CAC and that this trial may lead to a treatment option for vascular calcification and subsequent CVD. “ Results from this trial will not be complete until October of 2017 and will likely be published many months after that. Until then, there is a compelling argument to look at vitamin K2 when there is a concern for cardiovascular disease. 

How do you know if this is an issue for you?

Look for these signs of possible vitamin K2 deficiency:

  • Suffer from a digestive disorder that can lead to fat soluble vitamin insufficiencies (Small Intestinal Bacterial Overgrowth or SIBO, Irritable Bowel Syndrome, Inflammatory Bowel Disease, Celiac Disease, Cystic Fibrosis)
  • Osteoporosis or osteopenia
  • Tooth decay
  • Elevated blood pressure
  • Calcification of the aorta, coronary arteries, or carotid artery
  • Calcification of the muscles, joints (osteoarthritis), tendons (calcific tendonitis), kidneys, or brain
  • Have had a previous stroke
  • Have had a previous heart attack
  • Diet low in liver, natto (fermented soybean preparation), pastured dairy (especially cheeses), and egg yolks 
  • Taking a high dose vitamin D supplements >3000IU per day
  • Have Chronic Kidney Disease and/or are on dialysis


Testing for Deficiency of K2

You can test a marker of vitamin K2 deficiency call undercarboxylated osteocalcin. This is a blood test offered by Genova Diagnostics that is called the Vitamin K Assay and it runs around $200 dollars. If you have high levels of undercarboxylated osteocalcin, it implies that you may have an issue with vitamin K2 insufficiency. Call your local Functional Medicine practitioner or Genova Diagnostics (1-800-522-4762) for more details.

If you have signs of deficiency or a lab test indicating a need for vitamin K2, you will likely benefit from increasing your intake of vitamin K2 containing foods and supplements. If you are taking the blood-thinning medication called Warfarin or Coumadin, you must consult with your primary care physician before taking any vitamin K or increasing vitamin K-rich foods in your diet. 

Case Study: 

A vibrant 70 year old women interested in Functional Medicine came in to see me recently.  At the age of 49, she received the diagnosis of aortic calcification and recurring calcification of the tendons. When she turned 53, her medical team added osteoarthritis to the mix and at 54 they topped it off with a decrease in bone density. Like a good patient, she was diligently taking her 1000mg of calcium and 4,000IU of vitamin D every day to increase her bone density. Based on her health history, this was likely a dangerous thing to be doing. 

At the same time vitamin D upregulates proteins to pull more calcium in, it also upregulates the protein (osteocalcin) to put that calcium in the bones. An increase level of osteocalcin means there is an increase need for vitamin K. Osteocalcin uses up vitamin K to become active. If a person is already deficient in K, this could make things worse. 

The calcification of the aorta, tendons, joints (osteoarthritis), and lack of bone density clued me in to the fact that she was likely difficient in K so she ran a Vitamin K assay to check. Sure enough...levels of undercarboxylate osteocalcin, and indicator of low K2 levels...were significantly elevated. This implied that her K2 levels were quite low and that both the high levels of vitamin D and calcium she was taking were increasing her circulating calcium levels. Without the K2 to put the calcium in the bones and keep it out of her tendons and vessels, her supplementation was likely contributing to her health issues. I recommend always considering K2 levels whenever taking supplemental vitamin D and calcium. If you want to dive deeper in to case studies, biochemistry, and functional medicine protocols, see our Progressive Practitioner Coaching Program. Use Promo Code MAKECHANGE for 50% off until June 3rd. 


There are two types of vitamin K2 that most people refer to when they talk about supplementation: MK4 and MK7.

MK4 is has a very short half-life (1-2 hours) so large doses at frequent intervals are required for optimal results. Numerous trials have shown benefit with bone health when people supplement 15mg of MK4 three times a day. 

MK7 has been found in the body up to 72 hours after dosing and appears to be even more efficient at lowering vitamin K dependent proteins than MK4. Therefore, smaller dosing is needed (100-400mcg). The cost of supplementation is usually considerably lower with MK7.

Vitamin K supplementation is considered safe, and there are no toxic upper limits for either vitamin K1 and K2.

It appears that each form of vitamin K is used differently in various tissues and organs of the body so a combination of various vitamin K forms from supplements and the diet may be ideal. Like all supplements, I recommend choosing a brand that uses the highest quality raw materials, has tested purity, and is free of contaminants and rancid carrier oils. My clients have found success using the Thorne Research 3-K Complete product along with the Thorne Vitamin D/K2 Drops. This combination assures significant levels of all forms of vitamin K, and vitamin D as well. You can view this YouTube video for my recommendations.

Foods Rich in Vitamin K2


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  19. IMAGE of K2 Food Sources adapted from-

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Thank you for this insiteful article!! I've been taking Vit. K2 with Calcium and Vit. D for quite awhile, but it seems I need to take it more than once a day. ?

Hi Maureen! Thanks so much for this question. Yes. Vitamin K2 in the form of MK4 needs to be taken throughout the day. Three times a day to be exact. The K2 in the MK7 form can be taken once a day. I hope that helps!

Deep heartfelt thanks for this information. Been looking for 5 years. For real. Glad I came across you on the Vitamin Summit. This poses to be a lifesaving game changer for me. You also listed your resources. Good on you! I am so grateful.

Hi Paul! Thanks so much for your comment. I am happy you are finding benefit from this information. Let me know if there is anything else you have wanted someone to blog about.

My mother in law had a stroke a year ago. She is also diabetic. She was put on blood thinners. She also takes a very high dose of vit D daily. I've tried to explain the necessity of K2 in relation to D (and calcium, A, etc) but she tells me she can't take Vit K on blood thinners. While I know K1 and K2 are different, I've also read that K2 inadvertently acts as a blood clotter. Thoughts?

Wow Nikki. This is a great question. Thanks so much for asking it. ALL forms of K2 will alter clotting factors. If you are taking vitamin K supplements while on vitamin K antagonist medications like Warfarin, you need to stop now and consult with your physician. They will have to monitor your INR which identifies how long it takes for your blood to clot. With that said, there are some interesting research articles implying that small doses of MK7 (<45mcg per day) may be used in the near future to protect people that are using these medications from having calcification of their vessels. Wishing you and your mother in law the best of health. ~ Tom

Dear Tom, I have been taking warfarin for 25 years . I have been diagnosed with Antiphospholipid Syndrome. I have to remain on warfarin indefinitely. I had a bone scan done 7 months ago and was told I was oesteopenic. My Vitamin D level was also tested and found to be 20 and I was put on Vitamin D3 supplementation. I then started researching and found the connection between Vit K2 deficiency and calcium not being deposited in the correct places. My hematologist forbad me from taking Vit K2 but I persevered and for the past month or so, my INR is steady. It has taken me 6 months to get to this point and it has been pretty scary. I have to take 15mg of Warfarin each day in order to maintain an INR level of 2. My question is - is the Vit K 2 getting through and doing its job or is the increased intake or Warfarin negating the supplementation? I would really appreciate an answer on this one as there is no information or support forthcoming from my doctors. Regards Roberta

You indicate that "all forms of K2 will alter clotting factors", this is very confusing as everything I have read indicates K1 is for clotting factors and K2 is for helping calcium get into the bones and teeth. How many forms of K2 are there?

Hello, regarding blood thinners and vitamin K2-M7, would you consider it also risky to take a daily low dose aspirin when also taking K2-M7? I have read a lot of conflicting information. One study said K2 actually helps protect from aspirin related stomach ulcers while aiding their blood platelet actions. Other so-called experts say the K2 only goes after calcium in soft tissue, but doesn't calcium help protect against blood clots from rupturing, which is often worse than a clot???

Is there any risk of too much K? What is the test for K? Is it part of a regular blood panel? It looks like I could have too much D daily. I live far north. Is that a determiner in what amount of D to take?

I am continually impressed with TOm Malterre's insight into what is causing us problems and how we can deal with it.

Tom, I sincerely thank you for this information, and also for the wonderful cookbooks and the Elimination Diet book that you and your wife have written! They have helped me and my family in many ways. After reading this article and listening to your webinar, I was curious if vitamin K2 is helpful with bone spurs - can it redirect the calcium in them as well?

I'm taking Vit K4 with calcium, but how much calcium should I take and what kind of calcium is best?

My husband was recommended to take K-2, MK7 as part of a regimen for a high PSA (which helped). We simply adjusted his Warfarin dose upward to keep the INR in the preferred range for his AF. However, now that he is on Xarelto (which uses a different mechanism) I do not know what the net effect of the K-2, MK7 is. He is also on Plavix and Fish Oil which have blood thinning properties. During a recent accident, he had injuries that bled and he did not bleed profusely. There was bleeding but it did clot in a reasonable time. I would like to know more about the MK7/Nattokinaise combo to maintain the correct balance.

I have been making natto and would like to know if I can avoid eating the soybeans by separating the slime from the beans by swishing in warm water and then drinking the slime water. Is the K2 in the slime?

I have 3 in and I am taking 75mg of Asprin. Is it safe for me to take vitamin K2

I started taking vitamin k2 (both kinds) and have been having insomnia. What do you suggest? I need my sleep!

Should I be taking K2 and Eliquis? I had a stroke 14 months ago. I need to get better. I'm getting along fair, but I want more.

Hi.Happy Easter to all!I was wondering if you could advise me on how much Vitamin K2 and how much Vit D3 I should take to get rid of some osteophytes or bone spurs that are on my finger joints,I have osteoarthritis,and as an Esthetician,it's become difficult to perform facials and massage techniques ,I want to continue doing what I love.Also,any idea how long before they go away?I happen to have Sibo with constipation,so this info is very helpful.

ik gebruik sinds 4 jaar 180mcg vitamine k2mk7 pet dag. Nu heb ik het idee dat mijn bloed dun is. Als ik een klein snijwondje heb valt er vaak een druppel bloed op de grond. Kan dit door deze vitamine komen. Ik gebruik geen bloedverdunners.

I hear how vitamin k2 is good for keeping arteries clear of calcium and flexible. But I also know that it's a coagulant. Can a person with a stent take a coagulant like vitamin k2? Sounds scary. Can't find any information explaining this. Thank you!

Can a person take liposomal 300iu of D3 with 100ug of Mk7 and big amounts say 30,000 vitamin D with a1000 ug Mk7 2-3 times a week trying to help with calcification.

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