Vitamin K: At The Crossroads Of Bone And Heart Health

Thursday, September 21st, 2017

Supplements are pretty popular among consumers, but fortified foods are gaining an edge as well. Vitamin k is one such vitamin that can be used to fortify food and drinks, but what are its benefits for consumers? By Dr Elaine Drummond, clinical & technology development specialist, Glanbia Nutritionals North America

With modern cuisine taking consumers farther away from their traditional diets, there is great scope for the food and beverage industry to fortify products. This not only adds value to the food, but also introduces new marketing opportunities. Vitamins are essential for life and optimal health and are, by definition, required to prevent deficiency diseases, such as vitamin C for preventing scurvy and vitamin D for prevention of rickets.

Since its discovery in the early 1930s, vitamin K has been recognised as the coagulation vitamin due to its crucial role in the blood-clotting process; in fact, the “K” in vitamin K is derived from the German word “koagulation.” However, it is now known that the K vitamins’ functions are not limited solely to the activation of clotting factors—in fact it is needed for a healthy heart and bones.

Vitamin K

Vitamin K represents a group of compounds—all fat-soluble vitamins that are essential for the body to utilise calcium for healthy bones, healthy arteries and soft tissues. The vitamin K family is divided into vitamin K1 (one molecule; phylloquinone) and vitamin K2 (a group of molecules called menaquinones). For the latter group, the molecules can also have different lengths; longer chain vitamin K2s are more completely absorbed and remain in the blood for the longest time, providing the most benefits.

Vitamin K1 is traditionally found in green leafy vegetables such as broccoli, spinach and kale and is needed for proper blood coagulation. However, it is poorly absorbed from fresh vegetables. Only about 10-20 percent of K1 obtained from such food reaches the circulatory system.

Vitamin K2 is made by bacteria and is therefore found in high quantities in fermented foods such as mature cheeses, curd, and natto. Natto is a traditional Japanese dish made of fermented soybeans that provides an unusually rich source of natural Vitamin K2 as long-chain menaquinone-7 (MK-7).

Numerous studies have found that natto consumption in Japan has been linked to significant improvement in vitamin K status and bone health. Increasingly, consumers’ preference for less traditional food reduces the likelihood of natural K2 consumption even further. For these reasons, supplementation with K2 would be beneficial to the consumer.

Formulating With Vitamin K

As a fat-soluble vitamin, both forms of vitamin K can work very well or poorly depending on the food matrix and certain manufacturing processes. The vitamins do best in fortified products that are at least partially lipophilic, such as dairy, plant-based or baked goods.

For these sorts of products an oil form of the vitamin may be the easiest and most cost-effective ingredient format. In the case of dietary supplements or ready-to-mix powders, a powdered version of the vitamin is preferred. Functional beverages are not out of question either, as suppliers are beginning to emerge with water-dispersible versions of both forms of vitamin K.

Vitamin K is also susceptible to alkaline pH (neutral pH is acceptable, but anything greater than 8 is unacceptable), light and oxidative conditions. Therefore, this should be noted not only in manufacturing conditions, but also in testing of end products using methods such as high performance liquid chromatography. Also, due to the vitamin’s sensitivity to light, packaging must also be taken into consideration when determining whether a functional food or beverage is optimal for vitamin K fortification.

A unique finished product format to consider is cooking oil such as olive oil or canola oil. Cooking oils offer a convenient delivery mechanism for fatsoluble vitamins and provide some trade-off against the negative effects of certain cooking oils.

Vitamin K Fortification

For Children

Research has shown that children may not be receiving a sufficient intake of vitamin K, particularly vitamin K2, which is problematic since a lack of this nutrient poses serious implications for bone health as the child grows. Studies have shown that daily supplementation with 45-50 micrograms (mcg) of vitamin K2 may support bone development from early childhood on.

Newborn infants generally have low vitamin K status. Vitamin K does not pass through the placenta or breast milk successfully, therefore the average intake of vitamin K in infants who are exclusively breast-fed during the first six months of life has been reported to be less than 1 mcg/day; this is approximately 100-fold lower than the intake in infants fed a typical supplemented formula. This is a good reason for breast-feeding mothers to consider supplementation with vitamins K1 and K2. Formula-fed infants stand to benefit from the fortification of formula with both forms of vitamin K.

As children get older, their intake of vitamin K may continue to be inadequate. One study that compared dietary intake and sources of vitamin K between children born in the 1950s and the 1990s showed that dietary vitamin K intake was significantly higher in the former (39 mcg/day) than the latter (24 mcg/day).

Further, with general changes in food habits (increasing intake of fast food and processed foods), food sources of vitamin K intake have changed significantly between the 1950s and the 1990s. It is therefore conceivable that children’s vitamin K intakes have been on a significant decline since 1950.

Marketing vitamin K fortified foods such as fruit snacks, drinks, yogurts, and cereal towards parents for their children opens up a new demographic previously unexplored.

For Bones

vitamin K2 in particular has also been discovered to play an important role in activating a protein, osteocalcin, which helps in the delivery of dietary calcium to the bones.

Calcium is needed not only for the bones and teeth, but also for a range of cellular processes. The hope is that diet can supplement enough calcium to help the body function properly and without having to access that stored up calcium.

Poor bone metabolism is a condition characterised by loss of bone-mineral density when the body does not take in enough calcium to keeping functioning properly. This leads to weaker bones which, with loss of density, are more susceptible to fractures. According to the World Health Organisation (WHO), this condition currently affects some 200 million people globally. Worldwide, one in three men are expected to incur bone fractures in the future, whereas lifetime risk of fracture for women is nearly one in two.

A recent three-year study of vitamin K2-MK-7 in 244 healthy women showed for the first time clinically the significant protection of the vertebrae and hips against bone loss. This was achieved with only 180 mcg daily of vitamin K2-MK-7. After three years of supplementation, maintenance in both bone mineral content and bone mineral density were statistically significant in the vitamin K2 group. Moreover, bone strength was statistically improved, demonstrating therapeutic benefits for the vitamin K2-MK-7 treated group as compared to the placebo group.

For Heart Health


Most people who supplement with calcium do so for its bone strengthening benefits that can help to decrease the incidence of fractures as one ages. However, sometimes the calcium gets lost along the way, building up along the walls of the blood vessels. Over time, this can lead to calcified arteries, high blood pressure, atherosclerosis or even heart attack and stroke when deposits ultimately block up the passageway and limit blood flow.

Vitamin K2 helps prevent all of this from happening by activating a protein called matrix GLA-protein (MGP). This protein binds to calcium in the arterial walls and shuttles it away. By acting as a calcium ‘street-sweeper’, it helps reduce calcification to maintain that all-important flexibility and healthy blood pressure.

In the same aforementioned three-year study of vitamin K2-MK-7 supplementation in women, significant benefits in improving age-related stiffening of arteries were seen in the vitamin K2 MK-7 group, but not in the placebo. In addition, the vitamin not only prevented stiffening, it also resulted in an unprecedented statistically significant improvement of vascular elasticity.

With vitamin K2, the two key proteins MGP and osteocalcin that are essential to vascular and bone health can therefore be activated to carry calcium effectively—away from the arteries and to the bones, where it is needed.

Looking Forward

Vitamin K represents a group of vitamins, of which vitamin K2 is generating great attention for its bioactive attributes. This alone sparks interest in order to satisfy the consumer who is constantly seeking the ‘next big thing’ in fortified foods. It is vital for good bone and heart health.

The old recommendations that calcium is needed for your bones remains true, however, scientists now understand that you need particularly vitamin K2’s MK-7 to direct that calcium to the bones and away from the arteries. This is why vitamin K2-MK-7 is an essential part of a healthy diet.

In fact, an ideal bone health formulation would include vitamins K2, D3 and calcium. Vitamin K2 is suitable for a range of food and supplement applications such as tablets, softgels and soluble powder; it represents a truly viable new addition to the fortification industry.