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Information, Effect, deficiency, dosage, side effects, overdose
At first glance, arteriosclerosis and osteoporosis appear unrelated yet both conditions share key similarities. They become more common with age and develop gradually over decades. Often they remain unnoticed until a serious event occurs such as a heart attack or bone fracture. While their symptoms and effects differ recent research reveals a surprising link between the two through vitamin K2.
Vitamin K2 is an essential though frequently overlooked vitamin that plays a crucial role in maintaining both bone and cardiovascular health. It helps regulate calcium distribution in the body by directing calcium away from arteries where it can cause harmful plaque buildup and toward bones where it strengthens the skeletal structure. This unique action means that vitamin K2 not only supports the prevention of osteoporosis but also reduces the risk of arteriosclerosis and related cardiovascular diseases.
In this blog you will explore why vitamin K2 is so important how it functions in the body and practical ways to ensure you get enough to protect both your bones and arteries.
Vitamin K2 is a subtype of the vitamin K family that plays a crucial role beyond blood clotting. While Vitamin K1 mainly helps activate clotting factors, Vitamin K2’s primary importance lies in managing calcium in the body. It activates specific proteins called GLA proteins, which ensure that calcium gets deposited in the bones and teeth, where it’s needed for strength, and not in the arteries or soft tissues, where calcium buildup can cause problems like arterial stiffness and cardiovascular disease.
There are different forms of Vitamin K2, collectively called menaquinones (MK-n), where the number (n) refers to the length of their side chains:
Because of its role in calcium metabolism, Vitamin K2 supports bone health and cardiovascular health simultaneously — it helps build strong bones while preventing dangerous calcium deposits in arteries.
Vitamin K2 has a unique role among vitamins, it activates a special group of proteins called GLA proteins (gamma-carboxyglutamic acid), which are essential for blood clotting and calcium regulation.
So far, scientists have identified about fifteen different GLA proteins, but they suspect there may be over a hundred types throughout the body. Importantly, only Vitamin K2 can activate these GLA proteins.
Vitamin K2 induces a process called carboxylation in GLA proteins. This process enables these proteins to form “claws” (metaphorically speaking) that latch onto calcium ions. These claws allow the proteins to control and transport calcium properly. Without enough Vitamin K2, GLA proteins remain undercarboxylated and cannot regulate calcium effectively. This results in calcium migrating uncontrollably from bones into arteries and soft tissues.
Key GLA proteins include:
A deficiency in Vitamin K2 leads to poor calcium storage in bones, contributing to osteoporosis by reducing bone mineral density and causing bones to become porous and fragile. Simultaneously, calcium accumulates in artery walls, which may negatively affect the health of coronary arteries, kidneys, and the brain.
A vitamin K2 deficiency usually only becomes noticeable at a late stage. This is because this vitamin is involved in processes in the body that take a very long time. The first symptoms of a vitamin K2 deficiency are
Since the body does not produce sufficient amounts of vitamin K2, we are dependent on obtaining it from food. Vitamin K2 intake can also be increased by taking dietary supplements.
Older people in particular have an increased need for vitamin K2. Additional intake of vitamin K2 is also recommended for vegans and vegetarians, as vitamin K2 is mainly found in animal-based foods.
While a healthy intestine can produce small amounts of vitamin K, these amounts are very limited. Therefore, we rely mostly on dietary intake to meet our vitamin K needs. Unfortunately, evidence suggests that many people in Western countries do not consume enough vitamin K through their diet.
Natural vitamin K2, especially MK-7 from natto, is the most effective form of the vitamin. It has superior bioavailability and a longer duration of action compared to other forms of vitamin K. This means that more vitamin K2 enters the bloodstream and is available to the body for optimal health benefits.
Official guidelines in the EU recommend a daily intake of 10 to 70 µg of vitamin K (depending on age). However, these recommendations focus solely on activating blood clotting factors and are considered too low based on current research.
Recent studies show that a daily dosage of 100 to 200 µg of vitamin K2 is needed to fully activate all vitamin K2-dependent GLA proteins in adults, which supports bone, artery, and overall health.
For optimal benefits, a daily intake of 200 µg of vitamin K2 is recommended.
This dosage recommendation also applies if you are taking vitamin D supplements, regardless of the vitamin D amount. Proper balance between vitamin D and vitamin K2 is important for calcium metabolism and bone health.
It is virtually impossible to consume too much vitamin K2 through food. Even with dietary supplements, overdosing on vitamin K2 is highly unlikely due to the way the body metabolizes it.
Healthy individuals can safely take vitamin K2 supplements in higher doses without fear of overdose. For example, a Dutch study gave participants up to 360 µg of vitamin K2 (MK-7) daily, and even at this high dose, there were no adverse effects on blood clotting or other side effects.
Important caution: People who take blood-thinning medications (anticoagulants) should consult their doctor before using vitamin K2 supplements, as vitamin K can reduce the effectiveness of these medications.
Additionally, even at very high doses, vitamin K2 does not negatively affect vitamin D metabolism or cause an imbalance between vitamins D3 and K2. In fact, vitamin D3 requires vitamin K2 to carry out its functions effectively in the body.
Vitamin K2 is a natural and essential nutrient that is safe and well-tolerated, with no known side effects when consumed through diet or in appropriate supplemental doses.
“Even with high vitamin K intake, clotting does not increase beyond normal. The body knows how to regulate it.” — Prof. Dr. Cees Vermeer, Maastricht University
For more than half a century, it was believed that vitamin K was only necessary for normal blood clotting. In recent years, however, it has been the subject of numerous research studies.
These studies discovered matrix GLA protein (MGP), which is responsible for regulating calcium in vascular tissue. The activation of this protein depends on vitamin K2.
If there is a deficiency, MGP cannot be activated, which inevitably leads to arteriosclerosis, i.e., calcium deposits in the form of atherosclerotic plaque. This increases the risk of cardiovascular disease and causes a condition commonly known as “hardening of the arteries.”
In fact, healthy artery tissue contains 100 times more K2 than calcified arteries.
This also explains why patients who take blood thinners (e.g., coumarin, which inhibits the effect of vitamin K2) suffer from accelerated arteriosclerosis.
A groundbreaking animal study conducted at the Cardiovascular Research Institute of Maastricht University in the Netherlands suggests that vitamin K2 not only helps prevent arterial calcification, but may even reverse it.
In the study, laboratory rats were administered the blood thinner warfarin, which is known to induce vascular calcification by inhibiting vitamin K. After calcification was established, a subset of the rats was given a vitamin K2-rich diet. Compared to the control group on a standard diet, these rats showed a 50 percent reduction in arterial calcium levels, indicating a significant reversal of calcification.
Study leader Professor Leon Schurgers noted:
“These latest findings on the role of vitamin K2 intake are highly interesting for the treatment of cardiovascular diseases such as coronary heart disease. Our study is particularly significant because it has been shown that additional vitamin K2 intake can reverse arterial calcification.”
While these results are from an animal model and further human studies are needed, they provide promising evidence that vitamin K2 supplementation may be a powerful tool in managing or even reversing arteriosclerosis.
Normal calcium deposition occurs in two organs: bones and teeth. Abnormal calcium deposition occurs in three places: on the inner layer of the arteries (intima), where atherosclerotic plaque accumulates, on the muscle layer of the arteries (‘medial calcification’) and on the heart valves. Vitamin K2 appears to be the form of vitamin K that helps combat all of the above phenomena.
However, calcium has been considered a passive marker and not an active element in heart disease. One theory suggested that calcium was merely a residue of a previous ‘tear’, a scar from dangerous inflammatory activity of the soft plaque.
According to this theory, calcium should even be an indication of increased plaque stability, since the ‘hard’ material itself is not susceptible to tearing. Accordingly, calcium would not play an active role in the development of atherosclerotic plaque. This argument has now been refuted by new observations.
Doctors and scientists are now focusing on monitoring and preventing calcium accumulation in the heart, as they know that calcium is a major component of atherosclerotic plaque.
Calcium accumulation therefore appears to indicate active growth of atherosclerotic plaque, and vitamin K2 deficiency appears to be the basis for this pathogenic process.
Taking vitamin K2 over a long period of time can inhibit the development and progression of age-related arteriosclerosis. This was shown in a study conducted with postmenopausal women.
Furthermore, daily intake of 180 mcg of vitamin K2 over a period of 3 years was associated with a statistically significant improvement in vascular elasticity. This study was published in the journal Thrombosis and Haemostasis.
“In women who took vitamin K2 as a dietary supplement, the progression of arteriosclerosis typical for this age group was not observed, and a statistically significant improvement in vascular elasticity was even observed compared to the placebo group,” said Dr. Cees Vermeer, head of the study and renowned vitamin K2 researcher at Maastricht University in the Netherlands.
“Our data show that additional intake of vitamin K2 actually has a positive effect on the heart and blood vessels.”
A study titled “Menaquinone-7 Supplementation Improves Arterial Stiffness in Healthy Postmenopausal Women” has brought new insights into the cardiovascular benefits of long-term vitamin K2 intake.
“This is the first study to show that taking vitamin K2 as MK-7 over an extended period has a beneficial effect on the cardiovascular system,” said Dr. Cees Vermeer, lead researcher and vitamin K2 expert from Maastricht University.
“Previous population-based studies showed an association between vitamin K2 intake and reduced cardiovascular risk, but this is the first interventional study with a direct cardiovascular endpoint.”
Study Design:
Key Findings:
Out of the 244 participants, 227 completed the study. The results showed that:
Biomarker Analysis:
The researchers also analyzed levels of dephosphorylated, uncarboxylated matrix Gla protein (dp-ucMGP), a recognized marker of vitamin K deficiency and an early warning indicator for arterial calcification.
The best-known GLA protein is called osteocalcin. You may have heard of it in connection with bone density. Osteocalcin requires vitamin K2 to store calcium in the bones. Under-carboxylated osteocalcin (osteocalcin without vitamin K2) cannot regulate calcium, which reduces the calcium content in the teeth and bones and makes them porous.
At the same time, calcium is deposited in the arteries. Studies have shown that vitamin K2 can reverse this process.
Bones are not static structures, they are dynamic, living tissues constantly being broken down and rebuilt. The skeleton consists of a hard outer shell and an inner matrix filled with living cells and minerals. Under normal conditions, the entire skeleton is renewed every 7 to 10 years.
This remodeling process is regulated by two types of cells:
As long as osteoblast activity exceeds osteoclast activity, bones remain strong and healthy. However, this balance is easily disrupted, especially when the body lacks key nutrients like vitamin D, calcium, magnesium, and particularly vitamin K2.
Osteoblasts produce osteocalcin, a vitamin K2–dependent protein that helps bind calcium to the bone matrix, increasing bone mineral density and structural strength. Without enough vitamin K2, osteocalcin remains inactive and unable to lock calcium into the bone, weakening the skeleton over time.
A vitamin K2 deficiency impairs bone-building activity and allows osteoclasts to dominate. This results in a gradual loss of bone mass, even if bones appear normal on the outside. Internally, they may become thin, brittle, and prone to fracture.
From around age 35, osteoclast activity naturally increases, causing bones to lose approximately 1 to 1.5% of their mass each year. When this breakdown accelerates or isn’t balanced by adequate bone formation, the condition progresses to osteoporosis.
Osteoporosis is especially common in postmenopausal women due to the sharp decline in estrogen, a hormone that supports calcium storage in bones. In fact:
As early as 1984, researchers found that patients with osteoporosis-related fractures had 70% lower vitamin K2 levels than healthy individuals of the same age. Follow-up studies have confirmed a strong link between low vitamin K2 status and reduced bone density.
One particularly alarming finding showed that women with the lowest blood levels of vitamin K2 had a 65% higher risk of hip fracture than those with the highest levels.
In Germany, an estimated 8 to 10 million people suffer from osteoporosis, and 700,000 in Austria. Osteoporosis-related fractures have become so widespread that:
These statistics highlight that osteoporosis is not only a serious health concern but also one of the costliest diseases for healthcare systems.
For many years, calcium and vitamin D3 have been the go-to supplements for maintaining strong and healthy bones. This makes sense, as 99% of the body's calcium is stored in the skeleton, with a small portion in the teeth and only about 1% circulating in the bloodstream. Calcium is essential for continuous bone renewal throughout life.
Vitamin D3 has traditionally been regarded as the primary "bone vitamin" because it promotes the production of osteocalcin, a key protein involved in bone formation. However, research has shown that calcium and vitamin D3 alone are not sufficient to build and maintain optimal bone strength.
Recent studies have demonstrated that vitamin K2 is just as important as calcium and vitamin D3 for supporting bone health. While vitamin D3 stimulates the production of osteocalcin, only vitamin K2 can activate it. Without this activation, osteocalcin remains ineffective and cannot bind calcium to the bone matrix.
A deficiency in vitamin K2 means that even with adequate calcium and vitamin D3, the body cannot efficiently incorporate calcium into the bones. Over time, this leads to reduced bone density and an increased risk of osteoporosis.
Studies on osteoporosis have shown that vitamin K2:
This combination makes bones more resistant to fractures, even under stress.
An important question follows:
What happens to calcium if it is not used to build bone mass?
In the absence of sufficient vitamin K2, the body is unable to direct calcium into the bones. Instead, calcium is deposited in soft tissues, particularly in the walls of arteries, where it contributes to arterial calcification and the development of atherosclerosis.
In fact, the body responds to a vitamin K2 deficiency by depositing large amounts of calcium in the arteries, leading to hardening of the arteries. This explains a troubling paradox seen in older adults: many suffer from brittle, calcium-deficient bones while also having hardened, calcium-loaded arteries.
Vitamin K2 and Bone Loss Prevention
In 2003, the Osteo Study demonstrated that vitamin K2 supplementation can prevent bone loss. Over a three-year period, two groups were monitored: one received no supplements, and the other received synthetic MK-4 therapy (a form of vitamin K2). The results clearly showed that participants taking vitamin K2 experienced significantly less bone loss, confirming its protective effect on bone stability.
Natto Consumption and Osteoporosis Risk
Earlier research led by Masao Kaneki revealed a strong link between natto (a traditional Japanese food rich in MK-7, a natural form of vitamin K2) and improved bone health. Higher MK-7 levels from natto consumption were associated with:
These findings were supported by a 2006 study by Ikeda, which tracked 944 women aged 20 to 79 over three years. The study found a clear relationship between regular natto consumption and reduced bone density loss, highlighting the potential of MK-7 in osteoporosis prevention.
Vitamin K2 and Hip Fracture Risk
A 2008 study by Yaegashi et al., published in the European Journal of Epidemiology, found that among several nutrients (calcium, magnesium, zinc, vitamin D), natural vitamin K2 from natto had the strongest association with reduced hip fracture risk. The study concluded that vitamin K2 is a key nutrient for bone strength and fracture prevention.
Clinical Trials: Vitamin K2 Reduces Fracture Risk
A systematic review of all randomized, controlled trials lasting at least six months found the following:
Vitamin K2 was especially effective, reducing:
Long-Term Evidence: K2 for Bone and Heart Health
A 2013 study published in Osteoporosis International demonstrated the dual benefit of MK-7 on bone and cardiovascular health. Participants took supplements for three years, followed by comprehensive evaluations.
“Vitamin K2 ensures that calcium binds to the bone mineral matrix and is kept away from blood vessels,” explained Dr. Dennis Goodman, cardiologist and director of integrative medicine at NYU Langone Medical Center.
Without K2, calcium may deposit in arteries instead of bones, increasing the risk of arteriosclerosis, heart attacks, and strokes. According to studies published in the New England Journal of Medicine and Atherosclerosis, the biological age of individuals with arterial calcification can be up to 10 years older, emphasizing the need for preventive action.
Prevention Over Treatment
Osteoporosis is difficult to detect early, as symptoms often appear only after bone structure is significantly compromised, such as sudden fractures, back pain, or posture changes. Unfortunately, many medical treatments focus on later stages of the disease, when damage has already occurred.
Dietary supplements provide a proactive alternative, offering long-term support with fewer side effects and lower costs than prescription drugs. Experts recommend starting supplementation around age 40 and continuing consistently for decades to maximize the benefits.
An ideal supplement for osteoporosis prevention should include:
Lifestyle factors also matter. To support strong bones:
Bone growth is most rapid during childhood and puberty, with peak bone mass reached between ages 30 to 35. The higher the peak in early life, the longer bones can remain strong into old age.
However, vitamin K2 is essential for binding calcium into the bone matrix. Without it, even calcium and vitamin D3 cannot effectively support bone development.
A 2008 study by van Summeren showed that improved vitamin K status over two years in children resulted in:
Children’s bones are highly active, containing 8 to 10 times more osteocalcin than adult bones. This means they have a higher need for vitamin K2. Unfortunately, modern diets high in processed foods and low in vegetables have led to widespread vitamin K2 deficiency in children.
Experts recommend ensuring sufficient vitamin K2 intake in youth through:
An average diet in childhood, which is unfortunately often low in vital nutrients, can severely impair bone development and the health of the child's heart and circulatory system.
An inadequate diet is also often deficient in vitamin K2. Clinical studies have shown that vitamin K2 protects against bone loss and promotes bone density and strength while also protecting against arteriosclerosis.
Children's diets tend to be rich in calcium due to their high milk consumption. However, sufficient vitamin K2 must be present for the calcium to be incorporated into the bones.
Vitamin K, and K2 in particular, is, alongside vitamin D, the decisive factor in storing calcium in the bones. This allows a healthy bone matrix and optimal bone mineral density to be built up.
After childhood, vitamin K2 is responsible for maintaining mineral density and preventing bone loss. If not enough vitamin K is consumed, bone growth and bone density can suffer.
At the same time, vitamin K2 ensures that the calcium absorbed is not deposited in the arteries. A pronounced vitamin K deficiency can, under certain circumstances, lead to calcification of the heart arteries as early as childhood.
Vitamin K2 has the unique task of activating certain proteins in the body.
These include osteocalcin in the bones, matrix Gla protein (MGP) in the arteries, and coagulation factors in the liver.
Osteocalcin is responsible for binding calcium in the bone matrix. Without sufficient vitamin K2, a significant portion of osteocalcin remains inactive and therefore unable to bind calcium.
At the same time, matrix Gla proteins (MGP) prevent free-circulating calcium from attaching to the artery walls and depositing there, provided that sufficient vitamin K2 is available in the body.
Without the right form of vitamin K2, namely vitamin K2 as menaquinone-7, calcium cannot be properly processed in the body to build healthy, strong bones.
During childhood and adolescence, bones are extremely active and osteocalcin levels are 8-10 times higher than in adult bones. Children therefore need higher amounts of vitamin K2. Unfortunately, many children are deficient in vitamin K2. A vitamin K2 supplement can easily compensate for this deficiency.
Population-based and clinical studies have confirmed a clear link between better vitamin K2 status in children and the development of strong and healthy bones.
A study published in 2008 shows that improving vitamin K2 status in children over a period of 2 years led to stronger and denser bones.
A year later, the same research group showed that low-dose supplementation of vitamin K2 in the form of MK-7 in healthy prepubertal children increased osteocalcin carboxylation (activation of inactive osteocalcin).
In a study published in 2013, researchers tested 896 blood samples from 110 healthy volunteers (42 children and 68 adults). The researchers examined biomarkers that reflected the vitamin K2 status of the volunteers. To do this, they measured both circulating inactive MGP and inactive osteocalcin, both of which are proteins that are crucial for heart and bone health.
The researchers found that the children and adults with the most significant vitamin K2 deficiency responded most strongly to additional vitamin K2 supplementation.
Children and adults over the age of 40 showed the greatest vitamin K2 deficiency. Accordingly, these groups of people could benefit most from a vitamin K2 supplement such as MK-7.
That is why more and more doctors and nutrition experts recommend giving children additional vitamin K2 as a dietary supplement. This ensures that they get enough of this important vitamin during their growth phase.
A study conducted in the Netherlands shows that there is a link between taking vitamins K1 and K2 and a lower risk of type 2 diabetes. This was reported online on April 27, 2010, in the journal Diabetes Care.
Researchers at the University Medical Center Utrecht analyzed data from 38,094 participants who were between 20 and 70 years old at the start of the study. Questions about diet were analyzed with regard to the intake of phylloquinone (vitamin K1) and menaquinone (vitamin K2).
This study is the first to investigate the relationship between type 2 diabetes and vitamin K intake. The authors of the report suggested that vitamin K may influence diabetes risk via calcium metabolism.
However, changes in calcium and vitamin D intake did not influence the findings of the current research. A reduction in inflammation due to increased vitamin K intake, as suggested by the results of in vitro and observational studies, could also lead to improved insulin sensitivity and a reduced risk of diabetes.
“The results of this study show that both vitamin K1 and vitamin K2 intake may be associated with a reduced risk of type 2 diabetes,” the authors summarized. “With vitamin K1 intake, this risk reduction occurred at higher intake levels, while a linear relationship was observed with vitamin K2 intake.”
Experts, particularly those at Maastricht University, highlight the essential role of Vitamin K2 in maintaining optimal health. Here's a summary of their insights:
Importance of Natural Vitamin K2
Recommended Daily Dose
High-quality dietary supplements often include natural Vitamin K2 due to its superior bioavailability and effectiveness.
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