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Could Vitamin K2 Save Your Life?

Updated: 5 days ago

Vitamin K2 is essential for moving calcium into our bones

Vitamin K2 in drop of oil

If you are reading this, you probably already know that we need calcium for strong bones. You might also know that vitamin D3 plays a role. But you may not be aware that without vitamin K2, the calcium can’t get into our bones and can end up dangerously clogging our arteries instead.

The calcium paradox

It has long been known that people who take calcium supplements to prevent osteoporosis have a higher risk of heart disease. On average, for every bone fracture prevented by taking a calcium supplement, there are two potentially fatal heart attacks or strokes. This is known as the ‘calcium paradox’. How can people have too much calcium in their blood vessels but not enough in their bones, at the same time?

How does vitamin D fit in?

Vitamin D3 is made from sunlight by cholesterol in our skin cells. As we have become more aware of the dangers of skin cancer, many people now take it as a supplement instead. Vitamin D promotes the absorption of calcium from our gut into our body. So that’s great, now we can efficiently get the calcium into our bloodstream.

But that is not a safe place for it to be! Too much calcium in our blood vessels leads to calcium deposits in our arteries (atherosclerosis). Heart attacks are much more correlated with arterial calcification than they are with high cholesterol.

A 2011 study showed that calcium supplements, with or without vitamin D, increases the risk of heart attacks.


And a 2017 meta-analysis of 33 clinical trials showed that supplements of calcium, vitamin D or both did not result in fewer hip fractures.

So why is calcium being deposited into our arteries and not our bones?

How can we direct the calcium out of our blood stream – where we don’t want it – and into our bones and teeth – where it’s needed? That is where vitamin K comes in.

What is vitamin K?

Vitamin K is a fat soluble vitamin which comes in two forms: K1 and K2.

Vitamin K1

Vitamin K1 (phylloquinone) plays an important role in blood clotting. It is made within the chloroplasts of a plant’s cell, that’s the green part that captures sunlight. So it is abundant in green leafy vegetables (‘phyll’ comes from the Greek word for leaf). We get plenty of vitamin K1 in vegetables such as kale, spinach, silverbeet and broccoli and also some fruits such as blueberries and kiwifruit.


Because blood clotting is so essential to our survival, our bodies recycle vitamin K1 so that some is always available for emergency use. We are rarely deficient in this important nutrient. However, that is not the case for vitamin K2.

Vitamin K2

Animals that graze on green pastures convert much of the vitamin K1 they ingest into vitamin K2 (menaquinone), which accumulates in their fat. But humans convert very little K1 into K2, so we need to get it directly from our diet.


The type of vitamin K2 found in the butter, liver and egg yolks of grass-fed animals is called MK-4 (menaquinone-4). So the foods we have learnt to avoid for our heart health actually contain an important protective nutrient.


This could also explain the French paradox – the fact that people in France eat large amounts of saturated fat (butter, cream, cheese, pate, eggs and fatty meats) and yet have much lower rates of coronary heart disease than other northern Europeans.


There is another form of vitamin K2 that is made by good bacteria in fermented dairy products, such as cheeses, yoghurt and a Japanese fermented soybean dish called natto. This type is known as MK-7.

How vitamin K2 works

When we ingest calcium, vitamin D absorbs that calcium from our gut into our body. Along with vitamin A, it also helps to produce two special proteins: osteocalcin and MGP (matrix GLA protein). Vitamin K2 then activates the osteocalcin to attract calcium into our bones and teeth, making them stronger. Vitamin K2 also activates MGP to move calcium out of our blood vessels, which reduces our risk of heart disease.

Vitamin K2 word cloud

Without vitamin K2, calcium does not bind to our bones. So our bones get thinner and the calcium deposits instead into soft tissue, like blood vessels, kidneys and joints. Without vitamin K2 both osteoporosis and atherosclerosis get worse.


If we ingest only calcium, or even calcium plus vitamin D, but don’t get vitamin K2 as well, we continue to lose bone density and to calcify our blood vessels (the calcium paradox).

More research

One study in 1999 showed that women aged 38-63 who consumed less vitamin K in their diet had an increased risk of hip fracture.


Another study in 2003 showed that lower vitamin K intake was associated with low bone density in women.


A 2013 study showed that in post-menopausal women who took 180 mcg (micrograms) of the MK-7 version of K2 daily for three years, the density and strength of their bones were significantly better than for the women in a placebo group.

A 2019 study confirmed that the production of MGP ‘is stimulated by Vitamin D3, but it requires adequate Vitamin K2 intakes to be activated (similar to the bone-building protein osteocalcin). Once activated by Vitamin K2, MGP can bind calcium and escort it out of the areas where this mineral is destructive, namely arteries and soft tissues … No other productive mechanism for maintaining flexible blood vessel walls has been discovered, which makes MGP the only known and most potent existing inhibitor of cardiovascular calcification.’

A more recent study (2022), reported that ‘vitamin K2 plays an important role in the maintenance and improvement of BMD [bone mineral density]’, and that ‘Vitamin K2 supplementation is beneficial and safe in the treatment of osteoporosis for postmenopausal women.’

The research suggests that taking calcium and vitamin D increases the body’s need for vitamin K2. Without it, calcium cannot get into the bones and it builds up in soft tissues where it can cause harm.

How to get vitamin K2

Poster of foods rich in vitamin K2

We can obtain vitamin K2 from several animal sources, as long as they grazed on green grass, including (in descending order): emu oil; goose, chicken and beef liver; Jarlsberg, Gouda and Parmesan cheeses; egg yolks; butter; soft cheeses; blue cheese; cheddar cheese; chicken meat; and edam cheese. We can also get it from the Japanese fermented soybean dish called natto.

It is generally better to obtain nutrients from food rather than taking supplements. Vitamins and minerals in whole foods come with many other nutrients that work together, making them both safer and more potent. For example, calcium supplements can increase the risk of cardiovascular disease by 15%. However, dietary calcium (which is often associated with vitamin K2) does not increase the risk.


Nevertheless, our modern diets do not include as much animal fat from grazing animals as they once did and many people choose to take a vitamin K2 supplement.


Warning: If you take warfarin to thin your blood, then the added vitamin K2 will inhibit its action and you should avoid taking a supplement. Some other blood thinners work differently and may be compatible. Make sure you check with your doctor before taking a vitamin K2 supplement.

Vitamin K2 supplements

Vitamin K2 occurs in several forms, two of which are available as supplements.


MK-4 comes from animal fat and doesn’t last long within our bodies, so it needs to be ingested throughout the day. MK-4 supplements can be hard to find.


MK-7 comes from the Vitamin K2 made by the good bacteria in natto. It only needs to be taken once a day and is readily available in major supermarkets. (If you are allergic to soy, you can find versions made with fermented chickpeas instead).


Either way, as vitamin K2 is fat-soluble, taking it with food will boost its absorption.


The standard dosage for MK-7 in Australia is 100-180 mcg per day.

Nutrients work together

Many nutrients collaborate to protect bone density, including calcium, vitamin D3, vitamin K2, vitamin A, vitamin C, vitamin E, B vitamins, magnesium, phosphorus, boron and zinc. So we need to eat a healthy diet to cover all the bases. Fortunately, the popular Mediterranean-style diet does just that, with its emphasis on fruit, vegetables, whole grains, nuts and seeds.


This video does a good job of explaining how vitamin K2 works its magic, although I don’t recommend the dosages mentioned at the end. (8:47 mins).

And in this video a cardiologist in York, UK, explains the role of Vitamin K2 in preventing heart disease (10:26 mins).

Other Benefits

That’s not the end of the story. If, like me, you are intrigued by this vitamin, you can have some fun googling the increasing evidence for how vitamin K2 might also:

  • improve cardio output for athletes

  • slow the progression of Alzheimer’s disease

  • and help to prevent:

    • type 2 diabetes (because the osteocalcin protein it activates influences insulin sensitivity)

    • varicose veins (by strengthening the walls of capillaries)

    • dental cavities (by strengthening the teeth)

    • kidney disease (by reducing calcification)

    • Crohn's disease

    • some cancers.

The bottom line

If vitamin K2 can move calcium out of our blood vessels and into our bones, it might just save us from both hip fractures and heart attacks.

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