How does vitamin K affect the body?

, medical expert
Last reviewed: 10.08.2022

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Vitamin K is a fat-soluble vitamin. "K" comes from the German word "koagulation" - coagulation, that is, coagulation, thickening. Coagulation in the body refers to the process of hematopoiesis. Vitamin K is necessary for the functioning of a number of proteins involved in the process of blood clotting. How does vitamin K affect the body and why is it needed?

How does vitamin K affect the body and why is it needed?

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More about vitamin K

Vitamin K is not one chemical substance, but a family of chemically bound substances, which under the general name "vitamin K." Over the past 30 years, the vitamin has undergone great changes in terms of scientific understanding of its chemistry and functions. In the past, members of the family of vitamin K have traditionally been called vitamin K1, vitamin K2, vitamin K3. This terminology largely replaces another set of terms to describe that a more complex set of vitamin K compounds has now been established.

Other names for it today are Menadion; Menaphthon; menaquinone; Phylloquinone

Types of Vitamin K

All types of vitamin K are classified as large chemicals called naphthoquinones. In this category of naphthoquinones, there are two main types of vitamin K. Vitamin K The first type is phylloquinones, it is produced by plants. The second main type, called menaquinones, is produced by bacteria. The only exception to this rule includes a special group of bacteria called cyanobacteria that create phylloquinones instead of menaquinones.

Unlike some previous scientific assumptions, we get most of our dietary vitamin K in the form of phylloquinones from plant foods. In fact, up to 90% of dietary vitamin K our body receives in this form, and more than half of vitamin K comes from vegetables, especially green leafy vegetables. Many different types of bacteria in our intestines can create vitamin K in the form of menaquinones. Although the synthesis of vitamin K in our digestive tract can contribute to our need for a particular type of vitamin K, this dose is obtained by us less than previously thought.

What are the functions of vitamin K?

Vitamin K has several very useful functions for the body, and the main one is hemopoiesis.

Vitamin K promotes normal blood clotting

From the point of view of medical research, vitamin K is highly respected by all doctors for its role in healthy blood clotting. That's why the use of the letter "K" in the very name of this vitamin originally came from the German koagulation - coagulation.

Although blood coagulation can not be designated as an organism process, which is crucial for our daily state, it is, in fact, necessary. Whenever we get wounded skin, we need sufficient blood clotting to heal the wound and prevent excessive bleeding.

But we do not want too much blood coagulability, because when we are not injured, we do not want clots in our cardiovascular system to be formed and the functioning of the blood vessels was mistakenly blocked. Vitamin K is one of the key nutrients to maintain our ability to clot at the right level.

The process of blood coagulation

Vitamin K is located right at the center of the clotting process. If clotting factors are needed to successfully close the wound, it must somehow hold on to nearby tissue surfaces. This "stickiness" gives them a chemical measure called carboxylation. One of the amino acids for blood clotting is called glumatic acid, it is a component of blood coagulation. The second enzyme, warfarin, works as an anticoagulant and interrupts this process by blocking one of these enzymes (epoxide reductase).

When this enzyme is blocked, vitamin K can not be processed helps the blood clotting factor until it reaches the proper stickiness. For people with excessive propensity to form blood clots, an anticoagulant such as warfarin can save lives. Discoveries associated with the properties of warfarin led to our modern understanding of vitamin K as a key substance for healthy blood clotting.

Vitamin K protects weakened or broken bones

The properties of vitamin K for bone health have been fairly well studied. The most convincing is a study showing protection from fractures of bones when vitamin K is consumed in sufficient quantities.

Persons who consume insufficient vitamin K have a higher risk of fractures. In addition, women who have gone through menopause and started experiencing undesirable bone loss, vitamin K can help prevent future fractures. These bone benefits associated with vitamin K intake appear to depend on two main mechanisms.

Why do we need osteoclasts?

The first of these mechanisms is related to the type of bone tissue cells called osteoclasts. Osteoclasts are bone cells responsible for the demineralization of bones. They help to take minerals from bones and make them available to other body functions. While the activity of these cells is important for health care, a person does not need too many osteoclasts (or too much osteoclast activity), since this imbalance will mean too much demineralization of bones.

Two Important Mechanisms of Vitamin K

Vitamin K allows our body to keep this process under control. One form of vitamin K (MK-4, also called menatetrenone) has repeatedly shown that it can block the formation of too many osteoclasts and possibly initiate a programmed death of their cells (this process is called apoptosis).

The second mechanism is related to the role of vitamin K in a process called carboxylation. For our bones, in order to be optimally healthy, one of the proteins found in the bone - the osteocalcin protein - is needed, it must be chemically altered through the process of carboxylation.


Osteocalcin is not just a typical bone protein. It is a protein associated with bone mineral density (BMD) and for this reason is often measured in our blood, when doctors are trying to find out whether our bones are healthy. With too little osteocalcin protein, our bones get an increased risk of fractures. This undesirable risk seems particularly important with regard to fracture of the hip. Scientists have determined that vitamin K can significantly improve the situation.

Because vitamin K is necessary for the normal activity of the carboxylase enzyme, which allows the process of carboxylation of osteocalcin proteins in our bones, vitamin K can restore bones and strengthen their composition.

Vitamin K prevents calcification of blood vessels or valvular heart

A common problem in many forms of cardiovascular disease is undesirable calcification (calcification), build-up of calcium in tissues, which, as a rule, passes unnoticed. This build-up of calcium leads to the fact that the tissues become too strong and cease to function properly. When calcium accumulates in the arteries, it is usually called hardening of the arteries.

The direct way to slowing the build-up of calcium in the walls of the arteries is to maintain sufficient supplies of the special protein MGP in the body. MGP, or a matrix of Gla proteins, directly blocks the formation of calcium crystals in blood vessels. In other words, the heart-protective benefits of MGP in the prevention of calcification depend on vitamin K.

The researchers found that people with vitamin K deficiency have a higher risk of blockage of the arteries than people with a healthy intake of vitamin K.

Other important roles of vitamin K

Researchers continue to study a wide range of medico-auxiliary roles of vitamin K. At the forefront of this study of its role in three main areas:

  1. protection from oxidative damage;
  2. proper regulation of the body's inflammatory response,
  3. support the brain and nervous structure of the body.

Regarding protection against oxidative damage, vitamin K does not work directly as an antioxidant in the same manner as other antioxidant vitamins (for example, vitamin E and vitamin C). However, phylloquinone and menaquinone (forms of vitamin K) are useful in protecting cells, especially nerve cells - from oxidative damage.

In the conditions of the inflammatory reaction, several markers of pro-inflammatory activity, including, for example, the release of interleukin-6 (IL-6), are significantly reduced if there is enough vitamin K in the body. Finally, vitamin K is known to be necessary for the synthesis of a very important constituent for the brain and nervous system called fats sphingolipids (in translation - squeezing, squeezing). These fats are crucial in the formation of the myelin sheath, which forms an outer shell around the nerves, and both forms of the vitamin

K - phylloquinone and menaquinone, have been recognized as effective in supporting the synthesis of these key nerve components. All these roles of vitamin K were found primarily in laboratory studies in animals and in laboratory studies on human cell samples.

What are the symptoms of vitamin K deficiency?

People with vitamin K deficiency, first of all, have symptoms associated with problematic blood clotting or bleeding. These symptoms can include severe menstrual bleeding, gum bleeding, bleeding in the gastrointestinal tract, nosebleed, light bruises, blood in the urine, prolonged clotting time, bleeding, anemia.

The second problem of vitamin K deficiency is bone problems. These symptoms can include bone loss (osteopenia), decreased bone mineral density (osteoporosis), and fractures, including common age-related fractures. For example, hip fractures. Deficiency of vitamin K provokes the deposition of calcium in soft tissues. This calcification leads to blockage of the arteries or problems associated with the function of the heart valve.

What are the symptoms of vitamin K toxicity?

Since no adverse effects have been reported due to a higher level of vitamin K intake with food, there are no documented symptoms of vitamin K toxicity. In animal studies, vitamin K was presented in an amount that reaches 25 μg per kilogram of body weight (or for an adult human body weighing 154 kg, equivalent to 1750 μg of vitamin K) without significant toxicity. For these reasons, the Institute of Medicine of the National Academy of Sciences of the United States decided not to set an allowable upper limit of vitamin K when revising its public health recommendations for this nutrient in 2000.

One of the important exceptions to the toxicity results are the synthetic forms of vitamin K, which are called menadione. Although this form of vitamin K can sometimes be converted by the body into non-toxic forms, studies have shown that there are undesirable risks arising from the consumption of menadione. This risk includes excessive oxidative stress for the body and, as a result, damage to various types of cells, including kidney and liver cells.

Based on these data, the US does not allow the use of vitamin K for sale as a food additive in the form of menadione. Menadione is also known as vitamin K3.

How does heat treatment affect vitamin K?

As a rule, vitamin K is fairly well preserved after cooking or storing food. Some sources warn against freezing vegetables due to potential loss of vitamin K, but who has seen studies that document this risk?

As for cooking, studies in the nutritional data laboratory at the US Department of Agriculture in Beltsville have shown that heating does not cause any serious loss of vitamin K in vegetables. In some cases, cooking increases the measurable amount of vitamin K.

Forms of vitamin K are found in chloroplasts - components of plant cells, cooking could destroy cell walls of plants and release some forms of vitamin K. The release of vitamin K from chloroplasts increases the availability of vitamin K in the body. But in any case, cooking vegetables does not affect their vitamin K content in a negative way.

Studies show that freezing and storing vegetables and fruits and heat treatment of these products do not cause excessive loss of vitamin K. Therefore, vitamin K does not depend on the consumption and processing of plant material.

What factors contribute to vitamin K deficiency?

Any health problems, particularly with digestion and absorption of nutrients, can contribute to vitamin K deficiency. These problems include health conditions such as inflammatory bowel disease, ulcerative colitis, celiac disease, small bowel syndrome and digestive tract operations (for example, resection of the intestine). Problems with the functions of the pancreas, liver, gallbladder can also increase the risk of vitamin K deficiency.

Because our intestinal bacteria help us absorb vitamin K, any painkillers that convert our normal intestinal bacteria can compromise the level of vitamin K. At the top of this list will be antibiotics, but also anticonvulsants, sulfonamide drugs and salicylate-containing drugs. If you regularly use the drugs of any of the above groups, we recommend discussing with your doctor their potential effects on vitamin K.

There is some evidence that the aging process itself can contribute to vitamin K deficiency. The reasons for this - the potential links between aging and vitamin K - are not clear. Changes in the total metabolism may be involved in this list along with other more specific changes directly related to vitamin K. This may be especially important to carefully evaluate our intake of vitamin K as we age.

How do other nutrients interact with vitamin K?

Studies of nutrients that interact with vitamin K have traditionally focused on the basic fat-soluble vitamins, namely vitamins A, E and D. Unfortunately, this study has shown mixed results. People who are on treatment with anticoagulants testify that their anticoagulant therapy and the level of vitamin K are exposed to high doses of vitamin E.

For this reason, both vitamin K and vitamin E intake for people undergoing anticoagulant medication treatment is needed. This consumption is determined with the help of a doctor. In healthy people who do not consume vitamin E, a decrease in the level of vitamin K has been proven. However, in some cases, higher doses of vitamin E (above 1000 mg) have shown that at this stage it begins to interfere with the function of vitamin K and often leads to hemorrhage.

In many ways, based on these haemorrhagic effects, the National Academy of Sciences of the United States in 2000 established an allowable upper limit (UL) of vitamin E 1000 milligrams per day.

Since calcium metabolism can be significantly affected by both vitamin D and vitamin K, researchers suspect some key interactions between these two fat-soluble vitamins. Nevertheless, the exact nature of this interaction has not yet been determined.

The excess of supplemental consumption of vitamin A (retinol) has shown that it interferes with the ability of vitamin K to coagulate blood. The amount of vitamin A and the level of vitamin K in adults, as a rule, is a dose of 10,000 IU (3000 μg) or higher.

Who needs an increased dose of vitamin K?

Vitamin K can play a role in the prevention and / or treatment of the following diseases:

  • Anticoagulant therapy
  • Fracture of bone
  • Chronic liver disease
  • Cystic Fibrosis
  • Arthritis hardening
  • Inflammatory bowel disease
  • Liver cancer
  • Pancreas cancer
  • Stones in the kidneys
  • Nausea and vomiting during pregnancy
  • Osteopenia (loss of bone mass)
  • Osteoporosis (reduction of bone mineral density)
  • Thrombosis

What foods provide vitamin K?

What foods provide vitamin K?

An excellent source of vitamin K is parsley, cabbage, spinach, Brussels sprouts, chard, beans, asparagus, broccoli, cabbage, mustard greens, turnip greens, greens, thyme, romaine lettuce, sage, oregano, cabbage, celery, cucumbers, leeks, cauliflower, tomatoes and blueberries.


Fermentation of food can be especially useful for increasing the body's vitamin K. A food that can ferment the vitamin K content is cheese. Swiss cheese Emmental and Norwegian cheese Jarlsberg are examples of cheeses fermented with the Proprionibacterium bacterium. These bacteria can create a large amount of vitamin K.

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A very special place should be given to fermented soy products. The bacillus is not the most famous microorganism used in the process of soybean fermentation. One fascinating aspect of fermented soy products is the potential ability of these bacteria to remain alive in our lower intestinal tracts after these foods are consumed and supply us with vitamin K2.

As in the case of the Japanese diet, fermented soy products are the most common source of vitamin K. Meat and eggs are the most common food sources of another form of vitamin K2. Remember that all forms of vitamin K, including K2, make a great contribution to our health!


Many kinds of salad contain a large amount of vitamin K. It is worth noting that an ounce per ounce basis, romaine lettuce can be about four times more vitamin K than a head lettuce given by studies conducted at the US Department of Agriculture.

Since vitamin K is fat-soluble, nutrients, foods tend to increase the amount of vitamin K when the product is less water. For example, vitamin K is based on tomato paste more than in fresh tomatoes.

Sometimes the outer leaves of plants can have a more concentrated content of vitamin K than the inner leaves. For this reason, it is very carefully and carefully to clean these vegetables from the skin while washing them under running clean water, and to clean other leaves and include in the food.

Depot for vitamin K

Vitamin K is a fat-soluble vitamin, so our body keeps it in adipose tissue and liver.

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Interesting facts about vitamin K

  • Vitamin K is used to reduce the risk of bleeding in liver diseases.
  • In the United States, Canada, the United Kingdom and many other countries, all newborns received injections of vitamin K to prevent bleeding, especially in the brain.
  • Children are born without any bacteria in the intestine and do not get enough vitamin K from breast milk to provide the body.
  • Although vitamin K deficiency in newborns is very rare, it is dangerous, so doctors in developed countries make injections to them.
  • Newborns at greatest risk of vitamin K deficiency are prematurely born. Mothers to reduce the risk of premature birth often give oral forms of vitamin K for 2 weeks before delivery.
  • There is increasing evidence that vitamin K improves bone health and reduces the risk of bone fractures, especially in postmenopausal women who are at risk of developing osteoporosis.
  • Studies of the male and female body also showed that vitamin K helps the health of the bones of athletes.
  • Foods that contain a significant amount of vitamin K include beef liver, green tea, turnips, greens, broccoli, cabbage, spinach, asparagus, lettuce and a dark green salad. Chlorophyll substances in plants that give them a green color contain vitamin K.
  • Freezing foods can destroy vitamin K, but heat treatment does not affect its content.
  • People whose body can not absorb a sufficient amount of vitamin K because of diseases of the gallbladder or bile disease, cystic fibrosis, celiac disease, Crohn's disease, will benefit more from multivitamins containing vitamin K than from a single vitamin K.

Daily adequate dose for vitamin K for children

  1. Infants under 6 months: 2 mcg
  2. Children 7 to 12 months of age: 2.5 μg
  3. Children 1 - 3 years: 30 mcg
  4. Children 4 to 8 years of age: 55 μg
  5. Children 9 to 13 years of age: 60 μg
  6. Adolescents 14 to 18 years of age: 75 μg

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Daily adequate dose for vitamin K for adults

  1. Men 19 years and older: 120 mcg
  2. Women 19 years and older: 90 μg
  3. Pregnant and lactating women 14 - 18 years: 75 mcg
  4. Pregnant and lactating women 19 years and older: 90 μg

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Interaction with medicinal products

Phenytoin (Dilantin)

Phenytoin disrupts the ability of the body to use vitamin K. Taking anticonvulsants (eg, phenytoin) during pregnancy or while breastfeeding can lead to a decrease in vitamin K in newborns.

Warfarin (Coumadin)

Vitamin K blocks the action of blood thinning medications, such as warfarin. You should not take vitamin K or eat foods that contain large amounts of vitamin K while you are taking warfarin.

Orlistat (Xenical, Alli) and Olestra

Orlistat, a drug used for weight loss, and alustra - these substances are added to some foods that can reduce the amount of fat that a person can absorb. Because vitamin K is a fat-soluble vitamin, these drugs can also reduce the level of vitamin K.

Drugs for lowering cholesterol

Bile acid, used to lower cholesterol, reduces the amount of fat that can absorb the body, and can also reduce the absorption of fat-soluble vitamins. If you take one of these drugs, your doctor may recommend vitamin K:

  • Cholestyramine (Questran)
  • Kolestipol (Kolestid)
  • Colsevelam (Welchol)

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Precautionary measures

At recommended doses, vitamin K has few side effects.

Vitamin K penetrates the placenta and is also found in breast milk. Pregnant women and women who are breastfeeding should consult a doctor before taking vitamin K and its supplements.

People with a rare metabolic condition called glucose-6-phosphate dehydrogenase (G6PD) should avoid vitamin K deficiency.

People who take warfarin (Coumadin) should not take vitamin K

Antibiotics, especially known as cephalosporins, reduce the absorption of vitamin K in the body. They can lead to a decrease in the level of vitamin K for more than 10 days, since these drugs kill not only harmful bacteria, but also bacteria that create vitamin K.

Talk to your doctor before taking vitamin K or giving it to your baby.


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