There has been a lot written on Vitamin K recently; and some of it in quite exciting terms. “The next Vitamin D” seems to be a common theme amongst reputable nutritionists and scientists.
The consensus is that Vitamin K is where Vitamin D was some years ago – on the cusp of research revealing how important a vitamin it is and how deficient many of us are in it. So what is Vitamin K and where does it come from? There are fundamentally two types of Vitamin K – K1 and K2:
Vitamin K1 is found in green vegetables and excellent sources are ‘greens’ like spinach, kale, broccoli and brussel sprouts. Vitamin K1 has been recognised as being important in maintaining a healthy blood clotting system. Vitamin K1 deficiency in infants and children has been linked to serious bleeding disorders.
Vitamin K1 is now coming toward the fore in terms of fighting Osteoporosis as the vitamin keeps our blood vessels from calcifying, whilst helping our bones retain calcium and develop appropriately. The basic Vitamin K1 action is started in our liver.
Vitamin K2 content in food is more ‘elusive’; the best source is ‘natto’ a popular Japanese dish. Fermented foods such as natto, cheese and sauerkraut are considered the better food sources of K2. Our intestinal bacteria produce Vitamin K2 however research now seems clear that this is of limited, or no benefit, to our body as it is passed out in our stools without being absorbed to nutritive effect.
The ‘action’ of Vitamin K2 in our body is to go straight to bones, vessel walls and tissues (but not the liver). Vitamin K2 like K1 is recognised as beneficial towards osteoporosis and cardiovascular diseases including arterial calcification prevention.
The more recent research emerging is generating excitement for K2 and its potentially positive effects in fighting Alzheimer’s disease and a range of cancers. Vitamin K2 may also reduce the effects of varicose veins and skin aging.
So what is all the excitement about in respect of Vitamin K? Well, the body of eminent research is growing and this indicates that Vitamin K may play a vital role in:
- Support against cardiovascular diseases including arterial calcification Support against Osteoporosis
- Support against a range of cancers including prostate cancer, lung cancer, leukaemia and liver cancer
- Support for brain and ‘cognitive’ health including fighting Alzheimer’s disease and dementia
In terms of Vitamin K food supplements there are several different forms of vitamin K2 and we will address these briefly as it is important if you are considering using a suitable supplement. The forms include ‘MK8’ and ‘MK9’ which come primarily from dairy products but research indicates that the other two forms ‘MK4’ and ‘MK7 are far more effective.
However MK4 (a synthetic product) has a limited ‘life’ in our body and MK7 seems to recognised as by far the best option for food based supplementation as it has a much greater ‘life’ in our body; hence it is more bioavailable and bioefficient. Thus you have much better chance of building up a consistent blood level of the vitamin. In fact MK7 is extracted from the previously mentioned Japanese fermented soy product called natto. Eating natto directly will of course give you good levels of Vitamin K2 in the form of MK7 – sadly most of us cannot tolerate the smell, texture and taste of natto!
Vitamin K2 Fighting Cancer?
Numerous reputable cancer research studies attest to the positive role of Vitamin K and these include:
A German study which indicated that vitamin K2 provides substantial protection from prostate cancer; “men taking the highest amounts of K2 have about 50 percent less prostate cancer”. (1)
A National Cancer Institute funded study indicates that vitamin K2 might help reduce the risk for non-Hodgkin lymphoma. “Researchers discovered that people with the highest intake of vitamin K2 had a 45 percent lower risk for this type of cancer, compared to those with the lowest vitamin K2 intake”. (8)
The European Prospective Investigation into Cancer study, found high intake of Vitamin K2 (as opposed to K1) leads to a reduced cancer risk; and indications of a thirty percent lower risk of dying from cancer (6, 7)
Vitamin K & Cardiac Health
The ‘Rotterdam Study’ showed that people who consume 45 mcg of Vitamin K2 daily live seven years longer than people getting 12 mcg per day. (2)
The ‘Prospect Study’ followed 16,000 people for 10 years. Researchers found that each additional 10 mcg of K2 in the diet results in 9 percent fewer cardiac events. (3)
Vitamin K2 & Osteoporosis
Japanese trials have demonstrated that vitamin K2 can reverse bone loss and in some cases increases bone mass in people with Osteoporosis. The evidence of further Japanese studies were pooled and the trial evidence shows that Vitamin K2 supplementation produces a 60% reduction in vertebral fractures and an 80% reduction in hip and other non-vertebral fractures. (4) (5)
So how does Vitamin K, and in particular Vitamin K2, lead to bone health and the fight against Osteoporosis? Without being too scientific this is the process:
> ‘Osteoblasts’ are cells responsible for bone formation
> ‘Osteocalcin’ is a protein produced by our Osteoblasts
> Osteocalcin is utilised within our bones as an integral part of the bone-forming process
> ‘Osteocalcin’ must be ‘carboxylated’ before it can be effective in the bone forming process
> Vitamin K functions as a ‘co-factor’ for the enzyme that catalyzes the ‘carboxylation’ of Osteocalcin
> Vitamin K2 has been found to be far more effective in this process than Vitamin K1
How much Vitamin K should we need?
According to Dr. Cees Vermeer acknowledged as one of the world’s top researchers for vitamin K, nearly everyone is deficient in vitamin K.
We need Vitamin K1 for blood clotting and our liver preferentially uses Vitamin K1 to activate clotting factors. But as we have previously noted our body needs Vitamin K2 too, particularly for bone health. Our body can convert Vitamin K1 into K2 however studies show that the amount of K2 produced by this process alone is insufficient.
So the evidence indicates that Vitamin K2 is essential for bone health, plus a whole range of research suggests the vitamins beneficial effect in fighting cancers and cardiovascular diseases, but it is a nutrient the vast majority of us do not get in adequate amounts from our diet.
So, for Vitamin K1 eats lots of those lovely ‘greens’ we mentioned earlier. By all means try the ‘natto’ for the important Vitamin K2. However if you don’t like the taste of natto or want to supplement anyway the next best thing is a vitamin K2 supplement.
However Vitamin K is a ‘fat soluble’ vitamin and you must always take your vitamin K supplement with fat since it is fat-soluble and won’t be absorbed without it. Combined with fat, vitamin K2 bioavailability (absorption) can rise from 5% to 13%.
All fat soluble nutrients are better taken with a ‘lipid’ meal. But usually as supplements they come in a fatty substrate base which does the trick. If you are looking to get your Vitamin K1 from foods such as green vegetables it is best with say a touch of olive oil to add the fat component. So, the general rule, eating food for Vitamin K content the fat is important; taking supplements – not so.
Recommended Daily Allowance
The UK RDA for Vitamin K is 75ug. Dr. Vermeer suggests between 45 mcg and 185 mcg daily for adults and that “You must use caution on the higher doses if you take anticoagulants”. We would suggest 60ug a day as a safe effective dose, with higher levels for specific therapeutic application. As always we offer people to contact us or ask us for the name of a reputable health practitioner in their area; that way we can tailor advice based on individual circumstances.
Synergy between Vitamin K, Vitamin D and Calcium
Like most vitamins it is important to realise that Vitamin K works best when combined with other nutrients. In the case of Vitamin K is ideal partner, or synergistic partner, would seem to be Vitamin D.
According to the eminent vitaminK2.org website “Vitamin K2 activates osteocalcin, a protein required to bind calcium to the mineral matrix, thus strengthening the skeleton. In circulation, Vitamin K2 participates in carboxylation of Matrix Gla Protein (MGP), the most potent inhibitor of arterial calcification known, lowering the risk of vascular damage”.
It would appear that this effect is more beneficial when combined with Vitamin D, and Vitamin D has long been known as beneficial toward bone health. Calcium is most recognised as being important for bone health and it would seem that for many people looking to ‘beat off’ Osteoporosis or maintain bone health that a combination of all three nutrients (Vitamin K, Vitamin D and the mineral Calcium) will be beneficial.
Increasing calcium to optimum intake level from food and food identical sources is good for your bones and at the right level and in the right form will not increase the risk of arterial calcification. But equally, Vitamin K protects your blood vessels from calcifying when in the presence of high calcium levels.
Remember the law of nature which says – the synergy of the whole is greater than the sum of its parts – and this is never truer than the nutrients synergy that exists between Vitamin D3, Vitamin K2 and other bone essential nutrients which include calcium and magnesium.
 Nimptsch K, Rohrmann S and Linseisen J. “Dietary intake of vitamin K and risk of prostate cancer in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Heidelberg)” Am J Clinical Nutrition April 2008;87(4):985-992
 Geleijnse JM, Vermeer C, Grobbee DE, Schurgers LJ, Knapen MHJ, van der Meer IM, Hofman A and Witteman JCM. “Dietary intake of menaquinone is associated with a reduced risk of coronary heart disease: The Rotterdam Study” November 2004; J Nutr 134:3100-3105
 Daniels, S. “Vitamin K2, but not K1, effective for heart health benefits: Study” NutraIngredients.com February 12, 2009
 Vermeer C, Shearer M J, Zitterman A, Bolton-Smith C, Szulc P, Hodges S, Walter P, Rambeck W, Stocklin E, Weber P. “Beyond deficiency: Potential benefits of increased intakes of vitamin K for bone and vascular health” Eur J Nutr. December 2004;43(6):325-335
 Cockayne S, Adamson J, Lanham-New S, Shearer MJ, Gilbody S, Torgerson DJ. “Vitamin K and the prevention of fractures: Systematic review and meta-analysis of randomized controlled trials” Arch Intern Med. 2006; 166: 1256-1261
 Nimptsch K, Rohrmann S, Kaaks R, and Linseisen J. “Dietary vitamin K intake in relation to cancer incidence and mortality: Results from the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Heidelberg)” Am J Clin Nutr (March 24, 2010)
 Daniells S (March 30, 2010) “Vitamin D may reduce cancer risk: EPIC study” Nutraingredients.com
 “Vitamin K may protect against developing non-Hodgkin lymphoma” (April 20, 2010)