Back to bare bones

Every year millions of people take calcium and vitamin D supplements thinking that they are helping improve the strength of their bones. The fact remains, however, that the body cannot direct calcium – the building block of the human skeleton – without the addition of vitamin K2.

Nevertheless, we rarely hear about K2 and it is far less visible in the marketing efforts of supplement suppliers than, for example, vitamin D or vitamin C. While there are many vitamin supplements that undoubtedly benefit our health, the key role K2 plays in helping the body to absorb other nutrients should make headline news, and yet it rarely does.

Vitamin K1 is relatively well known for the important part it plays in blood clotting, but K2 not only helps the body direct calcium to bones but it plays a key role in improving the health of the heart. In short, it helps bones grow strong, but also keeps our heart pumping and our blood vessels flowing smoothly.

“There is scientific evidence that poor vitamin K status is associated with low bone mineral density and increased fracture risk,” says Katarzyna Maresz, president of the International Science and Health Foundation, who also runs a website dedicated to the lesser-known vitamin.

“Vitamin K2 is essential for the body to optimally utilise calcium, which is necessary to build healthy, strong bones,” Maresz continues. “K2 activates a protein called osteocalcin that binds calcium ions to the bone mineral matrix, thus strengthening the skeleton. But without adequate vitamin K intake, osteocalcin remains inactive, and calcium is not directed to create stronger bones.”

In clinical trials, the efficacy of vitamin K2 supplementation to support strong bones has been clearly proven. For example, a three-year study of vitamin K2 in the form of menaquinone-7, which involved 244 healthy postmenopausal women – a high-risk group for the bone-weakening condition osteporosis – indicated that vitamin K2 supplementation positively influenced bone mineral content and bone mineral density. Moreover, bone strength was statistically improved, demonstrating clear therapeutic benefits for the K2 group.

Furthermore, vitamin K2 in the form of Menatetrenone, also known as MK4, has been approved for the treatment of osteoporosis in Japan since 1995. Maresz also points to further clinical trials where the combination of menaquinone-7 vitamin K2 and vitamin D was proven to have a beneficial effect on bone mineral density in children with thalassemic osteopathy. Indeed, in the 2013 paper, ‘The efficacy of vitamin K2 and calcitriol combination on thalassemic osteopathy’, researchers found that survival rates and life expectancy of patients suffering from thalassemia major – one of a group of inherited conditions that affect haemoglobin – was significantly increased.

Healing for the heart

Health-conscious consumers are starting to recognise that vitamin K2 is essential for the body to support strong bones and healthy joints. What is less well known is its role in cardiovascular health.

“There are many new health areas that have been connected with vitamin K2, among them brain health, metabolic status, and even dental health,” observes Maresz. “Calcium is an important nutrient for bone health, however, recent scientific evidence suggests that elevated consumption of calcium supplements may raise the risk for heart disease and can be connected with accelerated deposit of calcium in blood-vessel walls and soft tissues.

As Maresz explains, K2 could be an antidote to heart problems because it is associated with inhibiting “arterial calcification and arterial stiffening”, meaning it could lower “calcium-associated health risks”.

In her 2015 paper ‘Proper Calcium Use: Vitamin K2 as a Promoter of Bone and Cardiovascular Health’, Maresz reports that adequate intake of vitamin K2 has been shown to lower the risk of vascular damage because it activates matrix GLA protein, which inhibits the deposits of calcium on the walls. She also notes that vitamin K, particularly as vitamin K2, is nearly non-existent in junk food, with little being consumed even in a healthy Western diet. As a result, vitamin K deficiency frequently results in inadequate activation of MGP, which greatly impairs the process of calcium removal and increases the risk of calcification of the blood vessels.

“Results from clinical trials have confirmed that vitamin K2 is cardioprotective,” she says. “In the study published in 2015 in Thrombosis and Haemostasis, researchers showed that menaquinone-7 not only inhibited age-related stiffening of the artery walls, but also made a statistically significant improvement of vascular elasticity.”

An elastic artery is a conducting or conduit artery with many collagen and elastin filaments in the tunica media, which gives it the ability to stretch in response to each pulse. Vascular elasticity is important for a healthy heart, as it reduces the risk of high blood pressure – a key risk factor for heart attacks and strokes.

“Many epidemiological studies also showed that vitamin K2 is cardioprotective and one study even stated that vitamin K2 intake was inversely correlated with early cardiovascular death to the same degree that tobacco use was positively correlated.”

In other words, taking K2 supplements could be as beneficial for the heart as quitting smoking. Yet that is not where the benefits of K2 end. It has also been shown to have a powerful anti-inflammatory effect.

Inflammation is part of the body’s natural healing process and is often a sign that a person is fighting off an infection. Unfortunately, the inflammatory effect can go into overdrive, causing an acute or chronic condition in which the body is damaging healthy cells, tissues and organs. Left unchecked, this can ultimately cause damage to DNA.

“It has been shown that low vitamin K status is correlated with a higher status of inflammatory markers,” says Maresz. “There might be different mechanisms that are involved in the modulation of immune response by vitamin K2. It has been shown that K2 can modulate immune response through non-canonical pathways, as well as vitamin K dependent proteins.”

Maresz cites another clinical study where vitamin K2 was effective as an anti-inflammatory nutrient in rheumatoid arthritis patients. In fact, in the 2015 paper, ‘Menaquinone-7 as a novel pharmacological therapy in the treatment of rheumatoid arthritis: A clinical study’, researchers remarked that MK-7 represents a new promising agent for rheumatoid arthritis in combination therapy with other disease-modifying antirheumatic drugs. “Growing evidence suggests a correlation between chronic inflammation and many health conditions including cardiovascular disease, diabetes, metabolic syndrome, inflammatory bowel disease and osteoporosis,” remarks Maresz. “Moreover, during aging, the dysregulation of the immune response leads to a chronic systemic inflammatory state. However, clinical research is needed to prove the benefits of vitamin K2 in inflammatory conditions other than arthritis.”

Out of the shadows

Given that it has so many beneficial effects – many of which target the health conditions that are becoming more prevalent in Western society – it is a surprise that K2 has not received more public attention, particularly as consumers become more focused on wellbeing and when the supplements industry is booming. There are, however, signs of change.

“These days I notice that consumers are more interested in new scientific findings than medical doctors, who on their side must wait on recommendation from the authorities, which of course takes time,” explains Maresz. “Based on the growing number of clinical trials on vitamin K2, it is clear that the understanding of this vital vitamin is much greater than it was ten years ago.”

With around 70 clinical trials focused on K2’s influence on health and general biology Maresz is encouraged that the vitamin is starting to be studied in greater detail.

“The ongoing studies are focused on cardiovascular health, kidney health, diabetes, fracture healing, Covid treatment and more,” Maresz observes. “Many research centres are involved in basic research focused on vitamin K2 and its mechanism of action. Additionally, some sales companies are involved in the research and collaborate with scientific centres. The knowledge around vitamin K2 is growing, as seen by the dramatic increase of scientific publications from 2000.”

As the volume of research grows and the public slowly becomes more aware of how K2 can benefit the body, one burning question remains – how can we get more K2 into our diet? Supplements are the obvious answer, given that factoring it into your normal diet means eating a traditional Japanese food made from soybeans that have been fermented with Bacillus subtilis, which has a slimy texture, a strong odour and is not universally liked.

“The best source of natural vitamin K2 is the traditional Japanese dish Natto, which is hardly consumed outside of Japan, also due to its particular taste and texture,” says Maresz. “Unless you eat Natto the only way to get a nutritional dose of vitamin K2 as MK7 is via supplementation.

“Natural vitamin K2 is produced during bacterial fermentation, and is present in foods such as fermented cheese, but only in very small amounts,” she adds. “In fact, the western diet is almost completely void of vitamin K2 as shown in studies in, among others, the Netherlands, which show the western population is low in vitamin K.”

Unless you are taking a supplement, the only way you can improve your vitamin K status is by eating a daily portion of Natto for breakfast. That may not be easy for many of us, so the best path for most will be to choose a K2 product that has been evaluated in clinical studies.