Vitamin K is an interesting vitamin.
It certainly isn’t one of the most well-known nutrients. Most people would think of vitamin D, potassium, magnesium or many other nutrients long before they think of vitamin K.
Vitamin K is frequently associated with its role in blood clotting. But, that's not what we're talking about here.
Instead, we're looking at vitamin K2 benefits for health.
Vitamin K2 is a specific version of vitamin K. It comes from different sources and has its own impacts. As a result, getting sufficient vitamin K isn't enough. You need to be taking in enough vitamin K2 as well.
Types of Vitamin K
There are three main forms of vitamin K.
- Vitamin K1 (also called phylloquinone). This plays a role in blood clotting and can reduce the risk of bleeding in some situations (1).
- Vitamin K2 (also called menaquinone). May play a role in activating proteins that then regulate calcium distribution in the body (2). It has many other potential implications for health as well.
- Vitamin K3 (also called menaphthone or menadione). This type is not discussed as frequently, as it is a synthetic form and has not been associated with as many health benefits. It may also have significant toxicity for some groups of people.
Vitamin K even has some interesting history, as researchers spent a long time looking for an elusive Factor X, which played an activating role throughout the body. This factor was eventually determined to be vitamin K (3).
Research has often just focused on vitamin K, rather than considering the specific subtypes. But, it's clear that these different versions can have significant implications for health. That's why this post is focused on vitamin K2.
Vitamin K exists in three forms: K1, K2 and K3
Synergistic Vitamin K2 Benefits
Much of the significance of vitamin K2 comes from the way that it is able to interact with other nutrients in the body. This means that some nutrients are much more effective in the presence of vitamin K2 than when vitamin K2 is not present.
Vitamin A, Vitamin D and Vitamin K2
Some research has indicated the presence of a relationship between vitamins A, D and K2. These three vitamins are thought to work in synergy with one another
One example of this is that supplementation with vitamin A and D results in the production of a protein known as osteocalcin.
- Osteocalcin plays a key role in organizing the way that the body uses phosphorous and calcium in the bones – which means that it contributes directly to bone health.
- However, osteocalcin only functions in the presence of vitamin K2 (4)
The role of vitamin K2 can be particularly important for people who are taking high doses of vitamin D, a topic that the Vitamin D Council discusses in depth.
One of vitamin K2 roles within the body is activating two proteins. One is osteocalcin, which I mentioned before. The other is called matrix GLA protein (MGP).
- Both of these proteins bind calcium and are involved in bone building and maintenance. K2 activates the calcium-binding function of the proteins, which means that it plays an indirect role in building and maintaining bones (5).
- Treatment with vitamin K2 and vitamin D3 has also been suggested for treatment of osteoporosis associated with diabetes (6).
- However, that approach comes from an animal study and outcomes from humans are still needed. Nevertheless, there is evidence that vitamin D and K do have some synergistic impacts on health (7).
This is a significant outcome because vitamin D deficiency is relatively common and a significant number of people are deficient in vitamin D (8).
Vitamin K2 interacts with vitamins A and D to promote health
Vitamin K2 Benefits for Bone Health
Many people take calcium supplements to improve their bone health and bone strength. However, many people do not realize that calcium is not the only nutrient that plays a role in promoting bone health.
As I mentioned previously, vitamin K2 is significant for bone health because of its interaction with vitamins A and D, but vitamin K2 also interacts with calcium. This means that the importance of vitamin K2 comes from the role that it plays in calcium regulation.
This means that if you don’t have enough vitamin K2 in your body, any calcium that you take may not do anything. In fact, low levels of vitamin K2 have been associated with a higher risk of atherosclerosis and heart disease (9).
Likewise, supplementing with some forms of vitamin K2 has been associated with reducing bone loss (10,11).
Having insufficient calcium is a significant health problem, and is associated with the development of fractures and osteoporosis.
As I mentioned before, K2 plays a role in the regulation of calcium.
- More specifically, K2 is able to ensure that calcium ends up where it is supposed to be in the body and prevents it from being in places in the body where it should not be.
- On its own calcium does promote bone health, but it does also tend to end up in places where it shouldn’t be (12). In particular, regardless of whether you take calcium supplements or get calcium through the diet, calcium can end up accumulating in the arteries, a process known as calcification
- This suggests that anyone taking calcium supplements should also be supplementing with K2, as K2 helps to ensure that the calcium actually does what it is supposed to. As a result, vitamin K2 can help decrease the risk of calcium-associated side effects.
- Because of this, supplementing with calcium and vitamin K2 can potentially be significant for getting the highest possible health benefits and minimizing the risk of undesirable complications, including a risk of heart attack (13).
Additionally, vitamin K2 is significant for bone health on its own, as the supplement acts to protect the body against fractures, this makes the supplement approach particularly relevant for the elderly (14,15).
However, as is often the case, not all scientists agree with the potential vitamin K2 benefits for health. Two extensive review studies suggested that at present there is not enough evidence for promoting vitamin K2 as a supplement (16,17). One more recent article suggested that vitamin K2 is promising but it's clear that more research is needed.
For people who need calcium, supplementation should not be the first step. Unlike many other vitamins and nutrients, there are many sources of calcium within the diet making it relatively easy for people to get sufficient calcium intake. Additionally, some foods that are rich in calcium also have high levels of vitamin K2, such as milk and butter.
Vitamin K2 can directly and indirectly promote bone health
The concern about calcification is a significant one, and there is growing interest in how prevalent calcification is and how it can be prevented. As I mentioned above, calcification is a process where calcium accumulates in the arteries.
- This can have many negative impacts on health, particularly as the accumulation of calcium can make it difficult for blood to pass through the arteries, increasing the risk of heart disease and other disorders.
- Because the symptoms of this condition are limited, many people may be deficient in vitamin K2 without realizing it.
- Additionally, calcification is the result of calcium being in the wrong place, which acts to increase calcium deficiency, as much of the calcium in the body is not where it is needed.
- This may be particularly significant for vegetarians and vegans because vitamin K2 is sourced from animal products, and the vitamin K1 variant from vegetables does not have the same health benefits.
Calcification is a process that can occur across many different diet and lifestyle types, and people can experience problems with calcification even if their calcium intake is lower than is recommended.
This indicates that lowering calcium intake is not the answer.
Instead, increasing consumption of vitamin K2 may be critical for improving health and reducing the level of calcification. Indeed, both vitamin K and magnesium have been suggested as potential approaches for decreasing calcification (18,19,20).
This is particularly important because calcification can result in negative health impacts that cannot be simply reversed.
Increasing vitamin K2 levels may reduce the risk of calcification
Other Vitamin K2 Benefits
Vitamin K2 has been proposed as a ‘missing link’ – one that may explain the development of many diseases and health problems in modern society.
- One example of this is that vitamin K2 has been linked to roles in insulin release and glucose tolerance (23).
- Likewise, vitamin K supplementation has been associated with a decreased risk of metabolic syndrome (24), as well as benefits for people with osteoporosis and heart disease (25).
- One placebo-controlled study did find that supplementation with vitamin K2 did decrease arterial stiffness (26). A relationship between vitamin K2 and arterial stiffness has also been suggested by other research (27).
Because vitamin K2 is associated with various health benefits, it has also been connected to life extension in general (28,29,30,31)
Research has also indicated that vitamin K2 is able to act as an inhibitor of calcification in the arteries (32), which can provide protection against heart disease (33).
- In fact, one large-scale study indicated that higher levels of vitamin K2 consumption were associated with a 57% reduction in how likely the person was to die from cardiovascular disease (34).
- Another study used observational approaches to look at the link between vitamin K and heart disease. The study involved 16,057 women. Of these participants, those with the highest intake of vitamin K2 also had a lower risk for heart disease. The authors estimated that every 10 micrograms of K2 was associated with a 9% decrease in heart disease risk. No relationship was found between K1 and heart disease (35)
A link has also been made between vitamin K2 and reduction in the risk of aortic stenosis, although randomized experimental studies are yet to be undertaken on the topic (36).
One interesting aspect of research into vitamin K and heart disease is the use of a calcium score (37). This score may provide a valuable way of detecting people who are at risk of artery calcification, even though they do not show symptoms (38,39).
The score comes from data obtained by a specific form of CT scan, known as an ultrafast CT scan or electron beam computerized tomography (40).
Researchers have been able to find links between this calcium score and the prevalence of heart disease (41).
These outcomes suggest that vitamin K deficiency may be a risk factor for the development of heart disease (42).
It’s important to note that while there is certainly some indication that vitamin K2 may reduce heart disease risk, the research isn’t conclusive. Instead, most of the research has relied on observational studies. While those studies can look at outcomes for large numbers of individuals, they are also limited in their ability to determine cause and effect (43,44).
Vitamin K2 may decrease heart disease risk
Some research suggests that vitamin K2 benefits for health may extend to dental benefits. This isn’t too surprising, as calcium is often linked to bone and teeth health, so it seems likely that vitamin K2 would be as well.
The protein osteocalcin which we talked about before is significant in dental health as well as in bone health.
In teeth, a key type of tissue is dentin, which grows under the enamel of teeth. Osteocalcin is involved in starting off a mechanism which then promotes dentin growth (45,46,47).
This connection suggests that having sufficient vitamin K2 may be significant for dental health.
Vitamin K2 may promote dental health, partly due to the interaction with calcium
There has also been some research suggesting that vitamin K might be relevant for cancer.
For example, two small studies indicated that vitamin K2 increased survival time from liver cancer and decreased the frequency of recurrence (48,49).
An observational study did also note that vitamin K2 was associated with lower risk of prostate cancer and advanced prostate cancer (50). However, the observational nature of the study limits the conclusions that can be drawn from it.
Indeed, with so few studies on vitamin K2 and cancer, and the fact that most of those studies were small, it is clear that we don’t know all that much about vitamin K2 and cancer at all.
While there is a chance that vitamin K2 may decrease the risk or increase survival for some cancers, it is certainly far too early to make any clear conclusions.
Vitamin K2 may also decrease cancer risk, although research is only in the early stages
Potential Negative Impacts
There are large and highly significant health benefits of vitamin K2 supplementation, but there is also some concern that vitamin K2 may be associated with side effects.
In particular, vitamin K2 is believed to play a role in coagulation, in a way that may interfere with people who are taking anticoagulant treatment (51).
One of the reasons that coagulation is concerning is that it can increase the risk of stroke.
However, one research study in this area found that vitamin K2 supplementation was not associated with an increase in stroke risk (52).
Aside from the issue with coagulation, vitamin K2 is a safe vitamin to take, but anyone taking anticoagulants should talk to a healthcare professional before starting with vitamin K2.
Vitamin K2 is considered safe, although you should talk to your doctor if you face problems with coagulation
There is a decent amount of evidence indicating vitamin K2’s role in bone health and its potential for reducing calcification. This does strongly reinforce the importance of having enough vitamin K2, especially as many people may be deficient.
However, there have been some significant limitations in the research (53).
- Many of the studies were observational or they were conducted in animals, not in humans.
- The amount of randomized controlled studies on the topic has been much lower than it needs to be to give a definitive answer on vitamin K2’s significance.
Nevertheless, this is an area that researchers are interested in and continue to focus on.
For example, one planned study is an experimental trial into the effectiveness of menaquinone-7 (a form of vitamin K2) for reducing the progression of coronary artery disease (54). The outcomes of that research will shed a lot of light onto how effective vitamin K2 really is.
More studies are needed to prove the implications of vitamin K2 for health
How to Get Vitamin K2 Health Benefits
Vitamin K is found in both animals and plants, but the K2 variant is only present in animal products. This includes meat, butter and eggs (55).
It is possible to get sufficient vitamin K2 from diet alone, particularly for people who focus on a diet that contains red meat and dairy. One of the best sources of vitamin K2 is from grass fed butter and other grass-fed dairy also provides a way to get vitamin K2 in the diet. Organ meats are another good choice.
The site Dr. Steven Lin provides a list of other sources of vitamin K2.
Additionally, it is also possible to get vitamin K2 supplements, which can provide the needed vitamin K2. While the best source of any vitamin or nutrient is in the diet itself, it is not always possible for people to get sufficient vitamin K2 from their diet for a range of reasons.
Because of this, supplements can be a particularly important way to improve health, especially for people who are deficient in some vitamins, like vitamin K2.
- One of the most important and effective types of K2 supplements is butter oil, which is associated with improvements to the skin as well as the advantages that vitamin K2 offers.
- Additionally, there are also synthetically generated liquids that have been developed as vitamin K2 supplements and can easily be taken in a dose-dependent manner.
One of the challenges with getting vitamin K2 benefits is that there is no simple way to determine whether you are actually deficient in vitamin K2.
There is a serum test available, much like there is for vitamin D. But, the test isn’t particularly accurate. It may tell you your vitamin K levels from food but may not be accurate in other areas. This occurs because of how vitamin K2 is processed in the body. You can check out the article at Wellness Mama for more details about the pattern.
One indication is whether you have any of the health conditions that are regularly associated with low vitamin K2. These include heart disease, diabetes and osteoporosis (56,57).
Additionally, you can get some idea of whether you have enough vitamin K2 in your diet by looking at what you eat. For example, people who eat grass-fed animal products regularly are probably fine for their vitamin K2 levels, but people who don’t may not be.
Types of K2
There are actually multiple types of vitamin K2 and understanding the difference between these can be important when it comes to choosing supplements or even choosing foods.
In general, the health benefits of the different types of K2 are similar, but the difference comes from what foods they are found in and how long they stay within the body.
The two main forms of vitamin K2 are menaquinone-4 (shortened to MK-4) and menaquinone-7 (shortened to MK-7).
- Menaquinone is another name for vitamin K2 while the numbers 4 and 7 are an indication of the chain length of the compound.
- MK-4 is the variant of vitamin K2 that is found within animal-based foods, egg yolks and butter and is generally considered to be the short-chain version of vitamin K2.
- In contrast, MK-7 is the long-chain version of the vitamin (there are actually multiple long-chain variants, but MK-7 is the most common) and is the most common in fermented foods
- A significant benefit of MK-7 over MK-4 is that it is a natural derivative, whereas the version of MK-4 that is found in supplements tends to be synthetic in nature.
- Additionally, MK-7 stays in the body longer, and you only need to dose with it once per day instead of multiple times like with MK-4
As a result, you should look for MK-7 in supplements wherever possible, even though both forms offer vitamin K2 health benefits. Some supplements may also contain both versions.
The MK-4 and MK-7 versions of vitamin K2 both offer similar benefits, although MK-7 may be slightly more effective for health
How Much Vitamin K2 Do You Need?
Currently, there is no consensus about how much K2 people should be consuming, but some studies have found health benefits from doses of around 180 to 200 micrograms.
This is much higher than most people get through the diet, suggesting that many people may be deficient in K2 without being aware of it (58,59,60).
Additionally, as I mentioned before, the amount of vitamin K2 that people need is associated with the amount of vitamin D that they consume. If a person is consuming a high dose of vitamin D, then a higher dose of vitamin K2 is also desirable.
- Unfortunately, research is still figuring out what these values actually are and the precise relationship between levels of vitamin D and vitamin K2 (61).
To make matters worse, the use of broad-spectrum antibiotics has been associated with decreases in vitamin K2 levels, as some vitamin K2 is produced by gut bacteria (62,63). Vitamin K2 is also lost quickly from the body (64).
However, vitamin K2 is not associated with any toxic effects (65). This may be because K2 operates differently than other vitamins, and its main role is simply to activate proteins.
This means that it isn’t really possible for K2 to do its role too much, as it cannot activate proteins that are not there to activate. So, there's no risk that you'll consume too much K2.
Optimum vitamin K2 doses aren't known but research has found benefits for 180 to 200 micrograms per day
Staying healthy can sometimes seem a complicated process. After all, there are so many different nutrients that our bodies need.
But, if we are eating healthy and focusing on whole foods, most of us will find that we are already getting all of the nutrients that we need.
Vitamin K2 is an interesting case.
It is often overlooked, but as you can see, there is a considerable amount of research pointing to its role in the body and in health. For example, the site Paleo Leap has also considered the vitamin in detail, as has Healthline.
Even though more research is needed in a lot of areas, it is certainly clear that people need to make sure that they aren’t deficient in the vitamin.
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