What is Vitamin K?

Vitamin K is an essential element that is found in plants or is produced by intestinal bacteria. An essential element, in this case a vitamin, is an organic component that contains carbon molecules, that are vital for life and have to be supplied externally, via food or nutritional supplements.

Vitamin K is a fat-soluble vitamin, i.e. they are usually absorbed by chylomicrons (fat molecules that circulate in the bloodstream after digestion), and that travel through the lymphatic system of the small intestine and in the circulation of blood throughout the body, being deposited in the tissues and remaining in those areas.

Note that chylomicrons are made up in almost a 90% of triglycerides, which are the main fat packages transported in the body.

Those who eat too much fat soluble vitamins can develop what is known as "hypervitaminosis", a term that literally refers to the presence of an excess of one or several vitamins.

The name vitamin K

The name given to this vitamin comes from the German word koagulation, since its role in regulating blood coagulation was discovered in Germany.

What is vitamin K?

Vitamin K does essential work with regard to bone health and regulates blood clotting.

Types of vitamin K

There are 3 types of vitamin K:

  • Vitamin K1, or Phylloquinone
  • Vitamin K2, or Menaquinone
  • Vitamin K3 or Menadione

K1 is found in green plants and vegetables, that are very rich sources of this substance due precisely to the fact that they require K1 to perform photosynthesis. K2 is generated from K1 and K3 by a type of bacteria and microorganism. It can be synthesised in our body by a conversion process that involves K1 and K3. We generally don't find K2 in a pre-existing form in the plant kingdom, unless these plants have been fermented or altered by bacteria. For example: bacillus natto. This bacterium can convert K1 to K2 and is frequently used in the production of fermented soybeans. The word "Natto" is probably widely used in dietary supplements.

Main sources of vitamin K

  • Vitamin K1: vegetables, especially dark green leaf vegetables
  • Vitamin K2: meats, eggs, dairy products, fish, fermented vegetable foods, fermented animal foods.

Foods containing vitamin K

Among the examples of the best foods that are rich in vitamin K are: kale, spinach, mustard, beetroot leaves, greens, cabbage, chard, turnip leaves, parsley, broccoli, brussels sprouts, cucumbers and prunes.

Vitamin K deficiency

Some people may have a lack of fat-soluble vitamins if they consume very little fat their diet, or the absorption of fat is compromised as a result of the oral intake of certain drugs, or if they are suffering from some kind of pathology. Cystic fibrosis is a disease that causes a deficiency in the synthesis of enzymes that are related to the absorption of fat in the intestine.

Other diseases related to a pathology of the intestinal system, such as ulcerative colitis or Crohn's syndrome, will also lead to a lack of vitamin K, because of a poor nutritional absorption.

Low levels of vitamin K intake also comes up as a dietary risk factor for osteoporosis. Taking a dose of vitamin K daily, via supplementation, can lead to a significant increase in bone mineral density, especially for those at risk, such as post-menopausal women.

Low vitamin K levels have also been linked to an increased risk of arthritis, where a low activity level of the proteins dependent on vitamin K in the joints is possibly an important determining factor for the increased risk.

Vitamin K effects

Benefits of vitamin K

Vitamin K in newborns

As mentioned previously, vitamin K is well known for its blood clotting properties. In certain contexts, the term "coagulate" can raise some concern, due to its unwanted processes (brain clot, blocked arteries...). However, this is far from the real benefits offered by this essential vitamin. Such is its importance that newborn babies are given an injection of vitamin K so as to avoid "hemolytic disease of the newborn" (HDN). This disease leads to a deficit of coagulation factors due to the newborn having a low level of this vitamin in their body. Vitamin K does not cross the placenta during foetal development and in addition the intestine lacks the bacteria that synthesise vitamin K after birth.

After birth, there is little vitamin K in breast milk and breastfed babies may be deficient in vitamin K for several weeks until intestinal bacteria begin to synthesise it.

Low levels of vitamin K can cause some babies to bleed severely, sometimes in the brain, which can lead to significant brain damage. This circumstance is called hemolytic disease of the newborn (HDN).

Vitamin K and the coagulation mechanism

Vitamin K is required to create blood clots and stop bleeding processes that could trigger a fatal outcome. To merely stop a simple cut on a finger, this vitamin is needed. Even so, the coagulation process is quite complex, and in the order of 12 types of proteins are required to fully carry it to the final stage of the process. Four of these protein coagulation factors require vitamin K for their specific activity.

The ability of the body to control blood flow after a vascular accident is essential for survival. To solve this, there is what is known as "hemostasis", which consists of the clotting process and the subsequent dissolution of the clot, followed by the repair of the injured tissue.

In this regard the presence of vitamin K is crucial to successfully undertake the clotting process:

  • Clotting factors are proteins in the blood that control bleeding. When a blood vessel is injured, its walls contract to limit blood flow to the injured area. Here, platelets adhere to the site of the lesion and spread along the surface of the blood vessel to stop bleeding.
  • At that moment they release chemical signals from small sacs within the platelets that attract other cells to the area to create a grouping, known as platelet plug.
  • On the surface of these active platelets, different clotting factors work and cooperate in a series of complex chemical reactions (known as a coagulation cascade) to form a fibrin clot. This acts as a mesh to stop bleeding.
  • The coagulation factors circulate in the blood in an inactive form. When a blood vessel is injured, a clotting cascade initiates and the coagulation factors are activated in a specific order, leading to the formation of the blood clot.

Vitamin K and bone health

Vitamin K is a unique nutrient for the proper maintenance of bone health, its role being fairly well-established in the treatment of this condition. People who are deficient in vitamin K have shown repeatedly that they have an increased risk of fractures. In addition, for women who have gone through menopause and have begun to experience loss of bone density, vitamin K can help to prevent future fractures.

According to research, our cells have a predilection for the K1 and K2 forms of vitamin K, where each one of them has a different role in bone health. In the case of K2, there are two types that the bones will capture more than others:

  • MK4
  • MK7

In fact, research is leaning towards vitamin K2, and all the attention is being directed at its subtypes. Vitamin K2 has a chemical structure composed of repeated units called preniles, with the most common forms of K2 being: 4, 5, 7, 8 or 9 prenile units, hence the abbreviations: MK-5, MK-4 and MK-7 MK-8, or MK-9.

The M refers to "Menaquinone", the scientific name. While standard human diets normally consist of around 10-20% K2, the proportions in the subtypes can vary widely. Foods fermented from soybean will contain a greater proportion of MK-7 and cheese contains MK-8 and MK-9.

The relationship between bone health and vitamin K mainly depends on two basic mechanisms:

  • Bone cells called "osteoclasts"
  • Carboxylation

Osteoclasts are responsible for bone demineralisation, in other words for obtaining minerals from the bones and bringing them to other systems in the body to be used for other purposes. While such activity is important for health, it is not ideal to have a high turnover of these molecules, since it can lead to a bone mineral imbalance. The K vitamin helps the body to regulate this process. In particular, MK-4 (called menatetrenone) prevents the formation of too many osteoclast cells by initiating their death (apoptosis).

The second mechanism involves vitamin K in a process known as "carboxylation". This process is directly related to the coagulation factors required for proper blood clotting. For optimal bone health one of the proteins that are found in them, called "osteocalcin", must be chemically altered during the carboxylation process. This protein is related to the measurement of Bone Mineral Density (BMD), and for this reason physicians perform blood tests to monitor the parameters of bone health. When a high level of osteocalcin proteins in our bone tissue are carboxylated, there is a greater risk of fractures.

Vitamin K can drastically reduce this situation. Vitamin K is required for the proper activity of the enzyme carboxylase, allowing the carboxylation of osteocalcin in bone tissue proteins. Vitamin K can redirect and restructure these bone proteins to the right place in the corresponding bone structure, thereby strengthening the composition of the bone.

Certain studies have found that vitamin K2 (MK-4 in particular) is especially useful in postmenopausal bone protection.

How and when to take vitamin K

Vitamin K comes in a variety of forms, where each will have a specific use, as well as a lower or higher limit depending on the form:

  • Vitamin K1: 50 - 1000mcg per day
  • Vitamin K1 (topically): 5%
  • Vitamin K2 (MK-4): 1.5mg - 45mg
  • Vitamin K2 (MK-7 and MK-8 and MK-9): 90 - 360mcg daily

It is a fat-soluble vitamin which we advised to ingest with food.

Do I need a vitamin K supplement?

Before you begin supplementation, prior consultation with a specialist is advisable and if necessary a series of tests could first be done to assess the situation. However if any of the following applies to you, the use of this supplement would certainly be favourable:

  • Use of certain medications, such as antibiotics, drugs to reduce cholesterol, the use of aspirin, which can drastically reduce levels of vitamin K in the body or interfere with its absorption.
  • Suffering from an intestinal system disease associated with the intestinal system, such as: Crohn's, ulcerative colitis, celiac disease, or any that prevent proper absorption of nutrients.
  • Post-menopausal women
  • Any person of advanced age at risk of suffering bone fractures

What does vitamin K combine well with?

The benefits of vitamin K, as we have seen, relate to improving the ability of the body regarding blood coagulation as well as the optimal maintenance of the skeletal system. In this last section we'll take a look at how other dietary supplements combine with and complement vitamin K.

We recommend a 'stack' of nutritional supplements to amplify the benefits of vitamin K in optimising the maintenance of bone health:

  • Vitamin D3: improves the absorption of calcium, increases bone mineral density and the strengthening of the bone itself, the daily dose will vary between 2000 - 10 000 IU.
  • Magnesium: its properties include bone support, the daily dose ranges between 200 - 400mg, including all sources
  • Calcium: a mineral with properties that fortify and help support the whole skeletal system; the daily dose should be around 500 mg, including all sources

Where to buy vitamin K?

Vitamin K can be purchased on this website. We recommend the aforementioned stack or at least including vitamin D3 supplementation along with the vitamin K.