Nutrition News Vitamin K2Cover

​Vitamin K2!


  • What Is Vitamin K2?

  • How Is It Linked To Healthy Bones?

  • Why Do We Need K2For Our Hearts?

  • What Is “The Calcium Paradox”?


What Do You Know About K2 And Arthritis?

Look Inside….


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A recent study in the European Journal of Pharmacology indicates that vitamin K2 has a significant effect on decreasing inflammatory markers in persons with rheumatoid arthritis. RA is one of the most debilitating conditions known within the human population. From Michael T. Murray, ND, in Vitamin Retailer 2015

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Vitamin K2     

Most of us know that vitamin K is needed for our blood to coagulate. Anytime that we suffer a skin rupture – a cut, a wound, or any other injury, even a pin prick – vitamin K comes into play.1 As important as this function is to our survival, vitamin K has other far-reaching implications for our health.

A great deal of research shows that a special form of K called K2 is integral to the distribution of calcium in our bodies, influencing both bone and heart health. In addition, emerging evidence indicates the usefulness of K2 in the treatment of rheumatoid and osteo- arthritis.

In this issue of Nutrition News, we discuss K2 as it relates to bone health and heart health.

Plus, we introduce evidence driving further research into the use of vitamin K2 with rheumatoid and osteo- arthritis.

Vitamin K is a complex of fat-soluble vitamins. Two types of molecules found in the complex are now known to be important to our health: Vitamin K1 (a phylloquinone) and vitamin K2 (a group called menaquinones2).

K1, found in green leafy vegetables, is involved in the coagulation process. It is used initially by the liver. However, it is poorly absorbed and is rapidly excreted. Less than 10 percent reaches tissues outside the liver, where it is needed as well. We need to eat a lot of leafy green veggies to satisfy the body’s vitamin K requirement.

Vitamin K2 is preferred by the non-liver tissues. K2 works in bone, in cartilage, and in the arteries and veins (together known as vasculature). K2 is produced in the intestines by bacteria and can also be obtained from fermented foods such as mature cheeses and curd (e.g., cottage cheese), tempeh, miso, good quality soy sauce, and a traditional Japanese fermented soy food called “natto”, by far the richest source.3 (Natto in photo above.) Vitamin K2 from natto is menaquinone-7. Called MK-7 it is used in quality vitamin K2 supplements.

Lab experiments, population studies, and clinical trials have correlated higher vitamin K status to clean, flexible arteries and strong, healthy bones. All forms of vitamin K activate vitamin K-dependent proteins, which are used in the liver for coagulation and also in the bones and soft tissues for calcium utilization. However, no amount of K1 can affect excessive calcium accumulation. Calcium clean-up is solely the job of vitamin K2 from MK-7.

Both heart disease and osteoporosis are long term degenerative diseases. In the body, these diseases are linked by a misappropriation of calcium. Further, that calcium link is related to vitamin K2. Research has revealed that K2 is essential to forming bone and to inhibiting arterial calcification.

One example is from The Journal of Clinical Endocrinology & Metabolism. The study, which involved 228 women, showed a connection between calcification (hardening) of the arteries in the breasts and reduced bone density. Reduced bone density threatens osteoporosis while hardening of the arteries (atherosclerosis) is a marker of heart disease risk. Thus, without sufficient vitamin K2, we find ourselves in the unenviable position of being at risk for both osteoporosis and heart disease.

Vitamin K2     


1  FYI: Hemophilia, the inability of the blood to clot, has nothing to do with vitamin K. It is the result of a hereditary genetic disorder or, far more rare, of a spontaneous gene mutation.

Persons with hemophilia do not bleed more intensely than normal people, but bleed for a much longer time. In severe cases, even a minor injury can result in blood loss lasting days, weeks, or never healing completely.

2  The forms of vitamin K are designated as K1, K2, and K3. K1, the coagulator, comes from plants; hence phylloquinone (phyllo- means plant).

K2, menaquinone, is produced by bacteria. It is found in some fermented foods and made in our intestines. MK-7 is the most important commercial menaquinone although a less effective MK-4 also exists.

K-3, menadione, is a synthetic form of vitamin K. It is not used in human supplementation but an online search reveals controversy surrounding its use in pet and animal food.

3  Paradoxically, natto is the same source as the enzyme nattokinase, the clot inhibitor and blood thinner.

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​Bone Up On Vitamin K2!

Calcium supplementation is widely believed to be the most effective non-prescription method of maintaining bone integrity. Although public education has stressed the importance of vitamin D-enhanced calcium, recent studies indicate that this is not enough to give us strong bones.4

For us to benefit from calcium, vitamin K2 must be present. (See  The Calcium Paradox.)

Most of us relate human bone to laboratory or Halloween skeletons. Few of us realize that bone is living tissue. It is comprised of a hard outer shell and spongy inner tissue matrix. In a process called “remodeling”, new bone cells are added where needed and old cells are removed. This process is particularly active during growth and following injuries. Our entire skeleton is replaced every seven years.

Bone tissues grow and develop most intensively during childhood and adolescence. This is when we build our greatest insurance against future bone fragility. By our mid-30s, we have achieved our maximum bone mass. After that, the balance between build-up and breakdown skews toward breakdown. It becomes extremely important to protect our bones with good nutrition, effective supplementation, and weight-bearing exercises. Children and menopausal women have the greatest need to build and preserve bone.

Bone is formed by cells called osteoblasts and broken down by osteoclasts. (Think iconoclast.) Osteoblasts secrete osteocalcin, a vitamin K-dependent protein which is activated by K2. Activated osteocalcin helps remove calcium from the blood and bind it into bone matrix. This bonding process does not take place without osteocalcin activity. In fact, measuring blood levels of unactivated osteocalcin gives a strong indicator bone health.

Vitamin K2 can completely prevent bone loss. Researchers involved in the 3-year Osteo study followed two groups of patients. The test group received vitamin K2 while the control group was not given supplementation. Results demonstrated unquestionably that taking K2 curtailed loss of bone strength for the entire supplementation period. This process does not happen with vitamin K1, the form needed for coagulation.

As mentioned, the richest food source of vitamin K2 is natto. Several Japanese studies using natto have shown that it not only activates osteocalcin more effectively, it reduces risk of bone fracture (Keneki) and appears to prevent the development of osteoporosis. (Ikeda)

Most recently, in the European Journal of Epidemiology, Yaegashi showed that while calcium, magnesium, zinc, and vitamin D are related to bone health, K2 from natto emerged as the key nutrient in producing a lower risk of hip fracture. Together, these studies reinforce the importance of vitamin K2 (as MK7) in the prevention of bone disorders.

​Bone Up On Vitamin K2!


For over 15 years, I have been advising newsletter readers of the importance of nutrients besides calcium that are necessary to building bone. Vitamin K, vitamin D, and magnesium are among these. SK, editor

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​How Old Are Your Arteries?

Heart diseases are the leading cause of death globally. These cardiovascular diseases (CVD) involve impairment of the heart and blood vessels. CVD often develops without any signs. By the time symptoms are detected, the underlying cause is advanced and difficult to treat.

Hardening of the arteries, atherosclerosis, is frequently the first stage of CVD. Over many years, displaced calcium becomes plaque deposits.  Calcification hardens and narrows the vessels, increasing their fragility. This impedes blood flow to and from the heart. Studies have shown that the amount of calcium in the arteries is an indicator of cardiovascular health.

Simply, you are as old as your arteries. Supple vessels with little or no plaque can lower your biological age up to 10 years below your chronological age.

As discussed, vitamin K2 delivers calcium to bone matrix by actuating osteocalcin. In CVD, the Ks activate a protein that inhibits calcification of the blood vessels. The protein is known as MGP (matrix gla protein). MGP circulates in the blood, attracting calcium and preventing it from binding to the vessel walls. This keeps the arteries clean and flexible. Lacking  vitamin K, MGP cannot do its job. This greatly increases the risk of dying from heart disease.

Findings of The Rotterdam Study (2004) showed that a high dietary intake of vitamin K2 (but not K1) has a strong protective effect on heart health.5 A group of 4807 men and women aged 55 and older took 45 mcg per day of vitamin K2 over several years.

A follow-up reported that the supplement reduced the risk of both arterial calcification and death from heart disease by as much as 50 percent – with absolutely no undesirable side effects!

Not only is vitamin K2 protective against CVD, some research indicates that a high intake of the supplement might actually be able to reverse the disease as well as lowering circulating cholesterol levels.

​How Old Are Your Arteries?


5  The Rotterdam Study began in 1990 and consists of three distinct groups of participants (cohorts) each of whom have entered the study at different times. If you want to know more about the findings of this very informative health study, I recommend going to the web.

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Vitamin K2 

Deficiencies & Doses

There are two kinds of vitamin K deficiency: acute and chronic. Neither is gender specific and they can happen at any age. An acute deficiency is what you would expect: unusual bleeding from gums, nose, or the intestinal tract. The ultimate consequence is death by hemorrhage. Although deficiencies are generally due to poor nutrition, a lack may also be caused by the use of anticoagulant drugs, prolonged use of antibiotics, gallbladder disease, and Crohn’s disease.

Newborns are especially susceptible to acute deficiency because sufficient vitamin K may not be transported across the placenta. Further, the intestinal tract of the newborn is sterile at birth, meaning there are no bacteria to produce the necessary amount of vitamin K1. Since 1961, newborns have been given vitamin K1 injections to protect them.

Chronic vitamin K deficiency is the focus of this newsletter. Because of a lack of alarming symptoms, chronic deficiency is less obvious and more dangerous. As emphasized throughout this issue, the end result of a K2 deficiency is increased risk of both heart disease and osteoporosis.

Chronic deficiency can be partly explained by changes over time in eating habits and in food composition. People eat far fewer leafy greens, rich in K1, than in the past. For example, in 1950, children got about 15 percent of their K from fats and oils and 55 percent from vegetables (excluding potatoes).

Today, they get 35 percent from fats and oils and only 30 percent from veggies. Sources are also less rich because sterile packaging conditions impede microorganisms (including the good ones) from penetrating our systems. Thus, we are making less K in our intestines than previously.

Vitamin K1 is simple: If your blood is coagulating efficiently, you are probably taking in and/or making enough. On the other hand, it is unlikely that any of us are getting sufficient vitamin K2. The widespread deficiency of this important vitamin could easily account – at least in part – for the nearly epidemic number of cases of cardiovascular disease, osteopenia, and osteoporosis.6

Supplement recommendations for vitamin K2 vary from 90-180 mcg. Again, the best sources are fermented foods, particularly natto.7 A 3 oz serving of natto (less than a quarter cup) contains 850 mcg of MK-7!

Fortunately, quality vitamin K2 supplements contain MK-7 from natto. These supplements are widely available at natural products stores. Research shows that 180 mcg/d of K2 as MK-7 promotes heart health by keeping arteries pliable and clear of plaque. It also promotes bone density.

Gene Bruno, MS, MHS, reports that there is no known toxicity level for either K2 or K1 supplements. This includes testing with 45 MG daily of K2 for 3 years in over 2000 postmenopausal women. (That MG is milligrams not micrograms.) The official recommendation for vitamin K1 is 120 mcg for men and 90 mcg for women.

There is one exception to the use of K supplementation:

The millions of people who are taking anticoagulant medications such as warfarin and coumarin cannot take vitamin K supplements. These medications are vitamin K antagonists, keeping the blood thin by interfering with clotting.8 Individuals who use them must avoid all forms of vitamin K. Unfortunately, those on the meds have been found to have 200 percent more soft tissue calcification than patients not taking them. People who are taking “novel anticoagulant” drugs (NOAC) can take K2 concomittantly.

Vitamin K2 

Deficiencies & Doses


Osteopenia means thin bones and is a precursor to osteoporosis.

Natto is available in Asian markets. However, the smell, taste, and texture of this food are generally considered to make it unpalatable to Westerners.

8  Read Nutrition News, “Supplement Your Prescription”, featuring an interview with Hyla Cass, MD. Dr. Cass draws upon her book of the same name. A major message of the interview is that there is no pharmaceutical without health consequences.


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​Vitamin K2 And The Calcium Paradox

A 5-year study of “healthy” postmenopausal women measured the bone-building effects of 1000 mg of calcium taken daily. The study revealed that calcium intake was beneficial for the bones; however, it was also associated with increased heart disease problems. Hence, “The Calcium Paradox”.

CVD and osteoporosis are highly correlated. Where one is found, the other is highly likely to be present. They are the leading causes of death and disability for men and women among all racial and ethnic groups. They both develop over decades often with no visible symptoms. They may not be diagnosed until an unexpected stroke or hip fracture occurs. As we have stressed throughout this newsletter, inappropriate calcium utilization is an underlying cause of both diseases.

In a US study involving 1000 postmenopausal women, hardened arteries were more common among those who also had osteoporosis or osteopenia. Findings in Japanese clinical research, in a large Norwegian study (5000+), and in a Danish investigation showed that low bone density was associated with atherosclerosis while calcification of the aorta was associated with the development of osteoporosis.

Researchers in the Danish study declared that aorta calcification was a site-specific predictor of bone loss and hip fracture risk. It bears repeating that taking natural vitamin K2 as MK-7 is associated with improved strength, density, and structure of bone. Secondly, studies link K2 with the inhibition of hardening of the arteries. Only K2 has been shown to stop and even regress arterial calcium accumulation.

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Vitamin K2 And Rheumatoid Arthritis

​Vitamin K2 Shows Promise In Rheumatoid Arthritis Treatment

Known for painful joints, RA is a chronic inflammatory condition that affects the entire body. An autoimmune disease which has been studied for decades, Michael Murray, ND, calls it

“a classic example of a multifactorial disease [involving] an assortment of genetic, dietary, and environmental factors.”

In 2015, Abdel Rahman and his team published their findings from a clinical trial with MK-7, and 84 participants (24 men and 60 women, average age 47 years) in varying stages of RA who were on standard drug regimens. Half the participants took 100 mcg/d for three months without changing their meds. Clinical and biochemical markers from both groups were taken before and after the three month period.

In the MK-7 treated group, the results showed a statistically significant decrease for the standard markers of inflammation: sedimentation rate (ESR), RA disease activity score of 28 joints, C-reactive protein (CRP) and MMP-3. MK-7 also increased the level of the active form of osteocalcin, an important marker of bone health. The benefits noted were directly related to increased MK-7 levels in the blood. The researchers concluded,

“MK-7 represents a promising new agent for RA in combination therapy with other disease modifying antirheumatic drugs.”

In commenting on this study, Dr. Murray, well-known naturopath, writes

“…standard medical therapy [of RA] is limited by its over-reliance on drugs… while failing to address the complex underlying causes.”

Most patients don’t get the relief they want and often have “to quit treatment because of the serious side effects the drugs cause.” Murray recommends the natural treatment of RA, stating, “Diet alone can be used to produce a complete remission in some patients and there are many key supplements that can help.”

For a discussion of a natural approach to RA, see the Encyclopedia of Natural Medicine, 3rd Edition (2012).

How About Osteoarthritis?

The Arthritis Foundation comments that low levels of vitamin K are linked to hand and knee osteoarthritis (OA). They also mention reduced fracture risk from the vitamin, recommending  “eating a serving of romaine or other dark green, leafy vegetables every day may cut the risk of hip fractures in half.” Further information on this topic is available by searching “OA and vitamin K2”.

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Vitamin K2    

Live Long And Prosper!

Higher intakes of vitamin K are linked with a longer life! A study in the May 2014 issue of the Journal of Nutrition links higher intake of vitamin K with a lower risk of dying from any cause over a 5 year follow-up.

This study included 7,216 participants in PREDIMED (studying the benefits of the Mediterranean Diet to older men and women). Researchers uncovered a 36% lower risk of dying from any cause and a 46% lower risk of dying from cancer.

Over the follow-up period, some participants increased their K1 and K2 intake. In comparison with those whose intake was unchanged, these individuals significantly improved their mortality. Specifically, death from cancer was lowered 36% by increased vitamin K1 and 59% by K2.

The researchers commented that results showed, for the first time, a link between increased intake of both dietary K1 and K2 and cancer mortality, plus all-cause mortality.