Vitamin K’s role in bones, circulation, cancer prevention and blood sugar levels
Vitamin K occurs in various forms and has a number of different biological function. The most recent research focuses on vitamin K2, which is of vital importance to the body’s calcium distribution and therefore has a crucial role in bone building and in the prevention of atherosclerosis. Vitamin K2 is also important for various proteins that are involved in energy turnover, blood sugar regulation, and cancer prevention, according to a review article that is published in BioMed Research International. Actual vitamin K2 deficiencies are considered rare, yet there are studies to suggest that many people lack the nutrient due to altered diet habits and the use of cholesterol-lowering medicine. The question is how much vitamin K2 do we actually need?
Our life expectancy has increased, and people today want to stay physically active and be able to manage on their own throughout life. Still, insidious problems such as osteoporosis and atherosclerosis can occur, and a sudden, unexpected fall may leave us with a fractured wrist, ankle, or hip or a blood clot. Even if you get enough calcium from your diet or from supplements, it is far more problematic if you lack vitamin K2, which we will take a closer look at in relation to bone health, circulatory health, and many other vital functions.
Bones are living tissue from cradle to grave
When talking about building strong bones, people usually focus on calcium and vitamin D, both of which are important for calcium uptake. But we also need vitamin K2, magnesium, and smaller quantities of other minerals. Bones also contain blood vessels, nerves, and cells. Two types of cells are responsible for managing the bone structure:
- Osteoblasts are bone-forming cells. They produce a hormone called osteocalcin, which strengthens bone tissue. Osteocalcin levels in the blood are used as an indicator of bone metabolism.
- Osteoclasts break down old and worn-out bone cells. Osteoclasts also remove calcium from the bones to regulate the pH value of blood in case the kidneys are unable to excrete excess acid.
Bone-building and bone-destroying processes
Bones are built during childhood and adolescence. Throughout life, worn-out bone tissue is replaced by new bone tissue. As long as the body builds more bone than it breaks down, our bones maintain their strength. However, around the age of 30-35 years, our bones start to deteriorate. Diet and lifestyle are highly important for the maintenance of strong bones, and vitamin K is often overlooked.
Vitamin K’s different forms and the importance of the nutrient
Henrik Dam, a Danish biochemist, was awarded the Nobel Prize in 1943 for his discovery of vitamin K. The nutrient is important for blood coagulation, but it also has other functions, and science is constantly finding new ones. Vitamin K is found in many different forms. Its main function is to serve as a co-factor in the production and activation of a host of different vitamin K-dependent proteins.
Vitamin K1 (phylloquinone)
Vitamin K1 (phylloquinone) is primarily known for its role in blood coagulation. It is mainly found in dark, leafy greens such as broccoli, parsley, spinach, cabbage, and beans. We only absorb around 10% of the nutrient from food in combination with fat. Vitamin K1 is important for blood coagulation and the vitamin is stored in the liver.
Conversion of vitamin K1 to vitamin K2
A lot of vitamin K1 is converted into vitamin K2 in the liver, but the conversion is limited by poor liver function. We can also convert vitamin K1 into vitamin K2 in the intestine, provided we have a well-functioning gut flora, but the amounts that are converted are typically too small for maintaining good health.
|Vitamin K1 and K2 are lipid-soluble nutrients. They are stored in the liver and are bound to LDL cholesterol when carried to the different tissues of the body.|
Vitamin K2 (menaquinone) is a group of chemical substances also called MK-2 to MK-14
The diet is an important source of vitamin K2, and we normally absorb 100 percent of the nutrient. Vitamin K2 is only found in fermented foods such as sauerkraut, kefir, soft cheeses like brie, and the Japanese soy product Natto, where the vitamin is produced by bacteria such as Bacillus subtilis during the fermentation process.
Vitamin K2 is stored in the liver but the nutrient is also found in the brain, pancreas, and sex glands. Our vitamin K2 stores are depleted comparatively fast if we do not get a regular supply from our diet. The body has a mechanism for recycling vitamin K2.
Vitamin K2 activates osteocalcin, which deposits calcium in the bones
In the 1980’s, science discovered that vitamin K2 is involved in the activation of the protein osteocalcin, which is responsible for depositing calcium salts in our bones. Vitamin K2, in collaboration with calcium, magnesium, and vitamin D, helps build and maintain strong bone tissue. Most bone-building supplements only contain calcium and vitamin D, which means that they cannot guarantee that their calcium content ends up in the bones.
Strong bones and health blood vessels – they are related
Later on, science discovered that vitamin K2 activates another protein, matrix Gla protein or MGP, which is primarily found in blood vessels. When vitamin K2 activates MGP, it binds to calcium ions and that turns vitamin K2 into a powerful tool for preventing atherosclerosis. MGP is also involved in bone building. Here, it is found together with osteocalcin.
If you lack vitamin K2 or if MGP is inactivated, it will eventually lead to atherosclerotic plaque, and it may also affect the bones, because they get too little calcium. That is why vitamin K2 is important for bone health as well as for circulatory health. Vitamin D increases the actual production of MGP. Scientific studies show that vitamin K2 lowers the risk of bone loss, bone fractures, and atherosclerosis. In Japan, the rate of these diseases is lower, simply because the population gets more vitamin K2 from sources such as Natto.
Another study shows that it is an advantage to combine vitamin K2 with bisphosphonates that are normally used as medical therapy for osteoporosis.
Vitamin K2, osteocalcin, and blood sugar levels
As mentioned, vitamin K2 is involved in the activation of osteocalcin, which deposits calcium in our bones. What many people are not aware of is that osteocalcin also plays a role in regulating insulin, which is the hormone that is responsible for channeling blood sugar (glucose) into cells
Many people have unstable blood sugar levels, and in the case of insulin resistance, the cellular uptake of blood sugar is reduced. This condition is part of what is known as metabolic syndrome (syndrome X), or pre-diabetes. Evidence suggests that lack of vitamin K2 increases your risk of insulin resistance.
It is already known that people with type 2 diabetes have an increased risk of atherosclerosis and osteoporosis. Studies carried out on diabetic mice reveal that supplements of vitamin K2 and vitamin D may be useful for diabetics that suffer from osteoporosis.
Statins inhibit the synthesis of vitamin K2
According to a study that is published in Expert Research Review of Clinical Pharmacology, cholesterol-lowering statins, contrary to conventional wisdom, increase the risk of atherosclerosis and heart failure. In the article, the scientists suggest several mechanisms that may be responsible for this. One mechanism is that statins inhibit the synthesis of vitamin K2 from vitamin K1
Vitamin K, cancer, and inflammation
Gas6 (growth arrest-specific 6) belongs to the group of vitamin K-dependent proteins. Gas6 is found in many of the body’s tissues, where it controls different biological processes, including cell development, cell growth, and cell adhesion. Gas6 is also important for cancer cell and their ability to self-destruct (apoptosis), which is a process that enables diseased and worn-out cells to eliminate themselves. Gas6 also counteracts inflammation, which is associated with cancer. Vitamin K2 generally lowers the risk of various cancer forms.
Our diets provided much more vitamin K2 in old days
This was because it was more common to use fermentation as a way of preserving foods. Today, we primarily resort to pickling, pasteurization, food preservatives, refrigerators, and freezers.
Widespread deficiency and poor utilization
Vitamin K deficiencies are considered quite rare. Surprisingly, recent studies suggest that they are widespread. Besides the fact that our diets are not properly balanced and that we do not consume all that many fermented food products, vitamin K deficiencies may also occur in the wake of prolonged use of medical drugs such as antibiotics, antacids, acetyl salicylic acid, cholesterol-lowering drugs, and blood-thinning vitamin K antagonists (Marevan/Waran) for preventing blood clots. It is essential for patients on this type of blood thinners not to take supplements of vitamin K.
How much vitamin K do we need?
There are different recommendations for daily intake of vitamin K1 and K2. In the case of suspected osteoporosis or atherosclerosis, it is recommended to take 150-180 micrograms daily.
Half that amount (75-90 micrograms daily) is the recommended amount for preventing osteoporosis and atherosclerosis.
Vitamin K2 immediately initiates the biochemical reactions that benefit the circulatory system and strengthen bones. However, it takes a year of supplementation before it is possible to analyze and measure the results. According to chief physician, Henrik Hey, at Vejle Sygehus in Denmark, 80 percent of the adult population in Denmark could benefit from taking vitamin K2 as a preventative measure or as part of their medical treatment against various diseases.
|It is possible to increase your vitamin K2 intake by consuming fermented foods. It is best to ferment the raw materials yourself, as the pasteurized (commercial) products do not contain all that much vitamin K2.|
Solmaz Akbari. Vitamin K and Bone Metabolism: A Review of the Latest Evidence in Preclinical Studies. BioMed Research International 2018
Nutrition insight. Role of Vitamin K in Bone Health Underlined in New Study. Jun 2017
Okyama et al. Statins stimulate atherosclerosis and heart failure: pharmacological mechanisms. PubMed.gov 2015
Guiling Wu. Targeting Gas6/TAM in cancer cells and tumor microenvironment. Melecular cancer 2018
Henrik Hey. K2 vitamin anbefalinger og advarsler. 2016
Hyung Jin Choi et al. Vitamin K2 Supplementation Improves Insulin Sensitivity via Osteocalcin Metabolism: A Placebo-Controlled Trial. American Diabetes Care. 2011
Shane Peterson, Søren Ejlersen & Ditte Ingemann. Fermentering. People´s Press 2015
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