When it comes to vitamins like C and D, most of us are fairly certain why we need them and what their functions are in the body. We are also aware how poor levels of these vitamins can affect our health in a number of ways. Unfortunately, the same can’t be said about vitamin K2.
Most of us know that vitamin K is needed for blood clotting and is found in green leafy vegetables such as kale, broccoli and spinach. While this description is true, it is neither complete nor gives full recognition to a vitamin that plays a much bigger role in many aspects of our health; and not just limited to blood clotting. But first a little bit about vitamin K family.
Vitamin K comprises of a group of fat soluble vitamins. This group is divided into Vitamin K1 and Vitamin K2.
Vitamin K1 at a glance
- Consists of one molecule called phylloquinone
- Found in green leafy vegetables
- Required for healthy blood clotting
Vitamin K2 at a glance
- Consists of a group of molecules called menaquinones or MKs
- Synthesized by bacteria in the gut and is also found in fermented foods such as natto and cheese.
- Required for a healthy bone turnover as well as a healthy cardiovascular system, besides being helpful in the blood clotting process.
Vitamin K and Our Health
Among other things, vitamin K works by activating proteins involved in binding calcium. It basically makes these proteins active to be able to bind to calcium. However, both vitamin K1 and vitamin K2 are involved in different processes. While vitamin K1 activates proteins involved in the blood clotting pathway, K2 activates proteins that control where calcium will go in the body.
Vitamin K2 activates many inert proteins that we need for a well-functioning body; especially those playing an integral role in keeping bones and the cardiovascular system healthy.
For example, vitamin K2 activates osteocalcin and Matrix Gla protein (MGP), proteins that regulate calcium metabolism and utilization in the body. By activating these proteins, vitamin K2 not only prods calcium towards the bone matrix and contributes to healthy bones and teeth; it also keeps calcium away from the arteries and prevents arterial calcification, thus keeping arteries supple and pliant. Vitamin K2 also keeps calcium from accumulating in other places like kidneys and the brain.
In Japan, vitamin K2 has been officially approved to treat osteoporosis.  Studies show that vitamin K2 supplements help to maintain bone mineral density  and prevent bone fractures. Vitamin K2 is also believed to reduce the risk of dying from coronary heart disease. 
What is important to note is that in most of the studies (that show that vitamin K2 lowers the risk of osteoporosis and heart disease), intake of vitamin K1 was found to have no effect, suggesting that:
- Vitamins K2 and K1 have different functions in the body
- The conversion of vitamin K1 to K2 in the body is not as efficient as previously thought. And this conversion is also not sufficient to meet the body’s requirements.
- Vitamin K2 is much more effective in reaching blood vessels, bones and other tissues than vitamin K1.
- While vitamin K1 efficiently reaches the liver, it also degrades pretty fast, unlike vitamin K2, which remains stable and active in the liver for a long time.
All of this means that vitamin K2 may be doing a better job of supporting overall health effects, which also include:
- Regulating sex hormones
- Improving insulin sensitivity and regulating sugar levels
- Improving energy
- Offering protection against cancer
Sources of Vitamin K2
Some of the vitamin K1 that we get from eating green leafy vegetables is converted into K2 in the body but as we just learned, this conversion is not very efficient. A small percentage of vitamin K2 is also produced by the gut bacteria.
The main source of vitamin K2, however, is fermented foods such as natto (a Japanese dish made of fermented soyabeans), curds, sauerkraut and cheese. But the vitamin is not found in processed cheese or processed cheese products. Some vitamin K2 is also found in animal products such as meat, eggs and dairy (raised on grass), but not enough to maintain an optimum level of vitamin K2 in the body.
So, if you are not eating fermented foods, you are likely to be deficient in this very important Vitamin and may need vitamin K2 supplements to provide your body with levels it needs to carry out functions that are dependent on vitamin K2.
What causes vitamin K2 deficiency?
- Poor intake of foods rich in vitamin K2
- Over-use of antibiotics that destroy gut bacteria
- Absorption issues because of age and gastrointestinal disorders such as celiac disease or Crohn’s disease
- Liver dysfunction
- Use of statins (cholesterol lowering drugs)
- Ishida Y. [Vitamin K2]. Clin Calcium. 2008
- MH Knapen et al. Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women. Osteoporosis International. 2013
- JM Geleijnse et al. Dietary Intake of Menaquinone Is Associated with a Reduced Risk of Coronary Heart Disease: The Rotterdam Study. The Journal of Nutrition.