Vitamin K was discovered in 1929 by a German scientist Heinrich Dam and named K for blood ‘koagulation’. How it does this is via activation of a Vitamin K-dependent (VKD) ‘gla’ proteins which stimulate various factors to make the blood clot.
However this is now known to be only the first of two forms – Vitamin K1 (phylloquinone) found in leafy greens and Vitamin K2 (menaquinone -MK) found in fermented foods especially natto.
Vit K2 is now known to be involved in both bone metabolism and arterial health and recent discoveries make it perhaps the greatest secret in maintaining cardiovascular health – way beyond cholesterol (which many believe has been unfairly demonised as it is there to repair an already damaged vessel).
There are various subdivisions of menaquinone including MK-7 (natural) and MK-4 (synthetic) and it is the MK-7 which has the greatest interest for heart health.
One really important point: the liver (where coagulation factors are formed) takes what it needs to prevent the risk of uncontrolled bleeding (a likely death). The remaining K is left for other tissues so the risk of K-deficiency mainly occurs in extra-hepatic tissues like bone, cartilage and arteries. These tissues also contain VKD proteins: osteocalcin (OC) and Matrix Gla Protein (MGP) respectively. The same process of carboxylation (addition of COO- is needed for activation
Let’s look firstly at what it does in bone.
Bone and Vitamin K2
K2 helps osteoblasts bind calcium from the blood and draw it into the bone. It also prevents breakdown by osteoclasts so preserving good bone structure and preventing osteoporosis. Note also that Vitamin K2 and D3 work in conjunction so must be taken together if sunlight exposure is not sufficient (which will be the case in winter in the UK).
Vitamin K2 and vascular health
Most everything you’ve probably heard about heart health is largely outdated. It is neither an excess of cholesterol or inflammation that is the cause of CVD – although both are involved. Much nearer to the upstream cause is an excess of Ca deposition in the soft tissues particularly arteries. The only known inhibitor of arterial calcification is activated MK-7). So lack of K2 leads to the formation of plaques which cholesterol then comes to bind and keep stable (as if it were allowed t. o break off would form a clot and kill you!) So cholesterol is the bandaid not the problem!
Most people are Vitamin K2 deficient – especially in the west where we seldom eat fermented foods. The Japanese are the highest consumers – some in the East eat natto every day. The average daily consumption needs to be 45mcg to give 50% reduction of arterial calcification and cardiovascular death. And it is a dose dependent relationship i.e. the more you have the lower your risk. Don’t forget that the order of usage is blood vessels then bone so the higher your intake the more benefit for your bone density.
NB Statins (which have been highly promoted for reducing the risk of heart attack actually weaken the heart because they inhibit recycling in the arteries!! MK is normally recycled 7 times on average so in order to reduce your risk of calcification you would need to take extra K2 when on them. For post-menopausal women, for instance (who shouldn’t be put on statins anyway), a dose of 180mcg/day MK-7 increases arterial health and is both preventative and remedial.
These two functions (bone and arterial) are not unrelated they are both symptoms of Ca dysfunction! This is because if you are limited in your intake of K2 you use up all your K2 stores to convert osteocalcin to its carboxylated active form (cOC) leaving nothing for the use in reducing calcium build up in the arteries.
K2 and Insulin Sensitivity
Well so much for bones and arteries. Now we turn to something that virtually no doctor knows about. K2 improves insulin sensitivity within 4 weeks of supplementation via the effect of osteocalcin reducing inflammation. This can drastically reduce your likelihood of developing diabetes if you have been diagnosed ‘pre-diabetic’! And that seems to work for men and women of all ages. By implication therefore it also reduces your risk of CVD which is also associated with insulin resistance (where larger and larger amounts of insulin have to be pumped out to keep blood sugar stable causing the receptors to basically become resistant). It reduced diabetes risk by 20% and prostate cancer risk by 35%.
Metabolic functions of K2 in mitochondria
Finally here’s an astonishing piece of information that is only recently becoming known. A new role of K2 in mitochondria (the energy producing organelles) which are significant in nerve health, muscle contraction and cardiac function and output. Mitos are, surprisingly perhaps remnants of bacteria that once fused with an animal cell in a mutually beneficial marriage of convenience! Now we know that bacteria produce K2 (hence their presence in fermented foods). Bacillus species use them for what is called a ‘redox’ function (reduction/oxygenation – the adding and removal of oxygen orthe removal /adding of Hydrogen (H2) ions. This process takes place within the mitochondria of our cells to produce the energy we need for functioning via the ‘energy currency’ of ATP.
Vitamin K2 increases the efficiency of the process by its ability to recycle the ATP via K – KH2 which stimulates the energy transport chain (ECT) in the mitos via its ability to act as an electron carrier. This often is the rate limiting step for energy of the cell. K2 is better than CoQ10 at rescuing mitochondrial function. And it may even be able to reverse neurodegenerative diseases like Parkinson’s (PD – which are largely due to the slow death of mitos (without replacement). It inhibits inflammation and the accumulation of reactive oxygen species (ROS – think of rust!) and may be a future treatment for PD and even multiple sclerosis (MS). It has been noted that people with MS even have ¼ of the K2 of non-MS patients. But for healthy people, even athletes, it is important to dose with K2 as it increases efficiency of heart mitos by 12% in 8 weeks! It also reduces cramping of muscles as it antagonises Acetylcholine the neurotransmitter of contraction. Finally it is arguably the most important anti-ageing nutrient as it increases mito efficiency and reduces oxidative damage by excessive production of free radicals or ‘ROS’ and thus mitochondrial death. This is known as the Mitochondrial free radical theory of Ageing (MFRTA). The efficiency of mitochondria is what makes the cell die when it drops to a certain threshold. So by increasing your K2 you improve all the functions of the body that require energy (that’s everything!).
K2 plays a significant role in improving the health of each of these systems
- Bone health – improves bone density
- Arterial perfusion – removes calcium from arteries
- Mitochondrial Health – improves function impacting on cardiac output, vascular health, muscle function
- Reduces speed of ageing – increases mitochondrial function, so each cell can produce more energy and we can regenerate dying cells.
- Prevents aging related tissue degeneration (inhibition of elastin and collagen calcification)
Nature’s Fountain of Youth! Dose required is 100-300mcg
The western population is sub-clinically deficient (in other words may not have overt deficiency symptoms but none the less are suffering).
 Diabetes Care 33:1699-1705, 2010
 Theuwissen et al. Food Funct. 2014 Feb:5(2) 229-34