In one of my previous articles I described the biological role of vitamin K, including differentiated influence of its two forms (vitamin K1 and K2) on the body. In this article I will concentrate more on the target activity of this compound, which has raised a lot of interest lately and which concerns circulatory system, most of all, the process of calcification of blood vessels and the development of atherosclerosis.
Before you read this article
Before reading this article, I suggest reading my previous article about the properties of vitamin K. The information found in that work can be the introduction for creating wider context of understanding the influence of the mentioned vitamin on circulatory system. Not only is this system intriguing, but also complex and it's worth understanding its substance and draw conclusions, which could be put into practice. You can find the link to the previous article below:
Atherosclerosis and blood vessel calcification
There's no doubt that atherosclerosis of peripheral arteries is one of the biggest challenges of modern medicine, both, in reference to medical treatment and prevention. The problem is, that the atherosclerosis processes are initiated quite early in our lives. During further periods of development we can basically just slow down their progress. Imaging diagnostic methods have let us reveal that about 90% of atherosclerotic plaque becomes calcified, and the intensification of this process is connected with narrowing blood vessels. The amount of stored calcium in the atherosclerotic plaque also correlates with the risk of death in case of some ailments, which accompany atherosclerosis.
The process of calcification raises a lot of interest in reference to the results it causes and the reasons, which are the base of this problem. Against the first thoughts coming to your head, the intensification of this process is not directly connected with the supply of calcium from diet. What's more, there may be such paradox in the body, that in the same time, you can observe the loss of calcium from bones (i.e. the place where it should be accumulated), and increased amount of it within blood vessels. It shows that the basic mechanisms of these processes are much more complicated...
Proteins regulating calcium conversion
In our bodies, there are unique proteins, of which biological role is to regulate calcium conversion. There are indications to think that the process of blood vessels calcification (i.e. gathering calcium in them) depends on their activity. A specific role is placed at protein called MPG (Matrix Protein Gla) and Gas6 (Growth Arest Specific protein). And here come a few factors, which could influence the activity of the mentioned proteins in adverse way, as well as influence the process of gathering calcium in blood vessels in direct or indirect way.
MPG and vitamin K
There's no doubt, that for the process described above the key factor is the disorder of calcium-phosphate balance (hyperphosphatemia, hypercalcemia). These disorders influence the release of osteocalcin, osteopontin and osteonectin, and they lead to the similar situation, as that from within the bone tissue (and which stimulates its mineralisation). And here comes vitamin K, which enables the MPG (after its carboxylation) to bond with the calcium and phosphate ions, what prevents from their stay within the walls of blood vessels. Depending the activity of MPG on the presence of vitamin K makes this vitamin an important factor, which takes part in the process of development of atherosclerosis. And we can influence the level of vitamin K in our bodies!
Is the theory confirmed in practice?
It's good to know that the participation of vitamin K and the MPG-type proteins in the process of blood vessels calcification is not the matter of speculations. Both, clinical observations done by dr Schurgers et.al, and experiments on animal model, where mice lacking MPG gene showed far-reaching calcification within blood vessels during only two months, seem to confirm that. However, the most important issue is that if we are able to influence the process of gathering calcium in blood vessels just by increasing the intake of vitamin K. The answer may be twofold – yes and no. The form of this vitamin causes the outcome.
Vitamin K is essential
Scientific studies show, that higher intake of vitamin K2, but not vitamin K1, is connected with lower risk of developing some diseases of circulatory system. It's very clear in case of form MK-7, as well as MK-8 and MK-9. But it doesn't mean that vitamin K1 has no influence in this matter (other studies suggest there is some influence), however, the impact of vitamin K2 is definitely more significant. I keep referring the matter of the influence of vitamin K on the process of blood vessels calcification to the context of activity of the MPG protein. But it's not the only protein taking part in the process of regulating calcium conversion.
Vitamin K or Gas6 protein
Apart from MPG protein, the other important protein, which takes part in the process of regulating the calcium conversion, is Gas6 protein (which is actually the growth factor, just like IGF). This protein is synthesized not only by smooth muscles cells of blood vessels (like MPG), but also by blood platelets, and it takes part in the processes of their aggregation. There is proof that this factor may be very important during blood clot formation. Additionally, Gas6 protects from calcification of blood vessels walls. It is connected, among others, with its antiapoptotic activity. According to the specialists who take care of this subject, such as Dr Proudfoot, the processes of apoptosis come before the processes of calcification. Here I have to add, that the activity of Gas6 protein depends on the presence of vitamin K. Without proper supply of vitamin K the amount of Gas6 is insufficient to protect blood vessels form calcification.
The subject of the influence of vitamin K, especially of vitamin K2, on the process of blood vessels calcification raises large interest in the scientific world. Intensive studies, which are to evaluate the influence of various doses of this substance on the mentioned aspects, are being lead currently. There is certain number of studies, which suggest that vitamin K2 may be the very significant factor for the pace of atherosclerosis development, although, the influence of this vitamin on the process of calcification seems controversial at some points, which is quite intriguing, remembering about the mechanisms of action of this compound. Here is an example of such research:
Reading publications like this, to which you can find link below, we can hope that there will appear more specific data in close future, which will determine the information concerning protective and medical potential of vitamin K2:
For those, who are more interested in this matter, there are also results of other studies done in recent years, and even months, such as those linked below:
Validity of supplementation
In the light of all available data, it's possible to risk a statement, that supplementation with vitamin K, vitamin K2- to be precise, may be justified in the prophylaxis of circulatory system diseases, such as atherosclerosis. It's hard to say, what the optimal dose is, but it is estimated that it ranges from 50 – 100mcg per day, but there is no precise information in that matter. What's more, it's hard to recognize insufficiency of this compound. Doses of 50-100mcg are rather safe and it's good to use them in permanent supplementation. However, there should be more precise data on this issue within next few months.
Vitamin K, most of all – vitamin K2, is a substance, which shows activities regulating the circulation of calcium in the body. This compound influences the activity of proteins, which protect blood vessels from calcification and, thanks to this, it may be an element of prophylaxis, or it may even support the treatment of atherosclerosis. However, there is the necessity of more extended studies, which would verify the efficiency of supplementation, as well as some methods, which would let us set precise optimal daily dose of this compound to prevent from insufficiency and during the periods of balancing it. I will come back to the topic of vitamin K2 in my further articles.