Which vitamin is a natural blood thinner?

Vitamin K products - what makes sense?

What's behind the vitamin K advertisement?

Vitamin K is often found in food supplements and is advertised, among other things, as contributing to blood clotting and healthy bones. While it is true that vitamin K is important for the body, it is naturally found in many plant-based (vitamin K1) and also animal (K2) Contain foods. Nutrition experts assume that the population is adequately supplied with vitamin K and that additional pills are not necessary.

Only two health-related advertising claims are allowed for vitamin K:

  • Vitamin K contributes to normal blood clotting
  • Vitamin K contributes to the maintenance of normal bones

On the other hand, the disease-related statements that vitamin K (not even K2!) protects against osteoporosis or vascular diseases.

What should I look out for when using vitamin K products?

The vitamin K compounds formed by microorganisms and plants are not dangerous for healthy people, even in high doses. Apart from rare, occasionally observed allergic hypersensitivity reactions, no symptoms of overdose are known. For this reason, the European Food Safety Authority (EFSA) has not set an upper limit value.

These vitamin compounds are approved for vitamin K in food supplements in Germany and other EU countries in accordance with EU Directive 2002/46 / EC, Annex II (version of 05.07.2017):

  • Phylloquinone (Phytomenadion, K1)
  • Menaquinone (K2)

Despite their different physiological importance and bioactivity, the recommended intake (except for dietary supplements) has so far not made a distinction between vitamin K and vitamin K.1 and vitamin K2 differentiated.

For the prophylaxis of thrombotic diseases, vitamin K antagonists (for example Marcumar), so to speak "opponents" of vitamin K, are often administered. This inhibits the absorption of vitamin K and delays blood clotting. If you have been prescribed such anticoagulant drugs, you do not need to change your diet to a diet low in vitamin K. However, you should definitely take additional vitamin K through dietary supplements or medicationwithout consulting your doctor first avoid as this can endanger the success of the therapy in the long term. As little as 10 µg of vitamin K.2 can negatively affect anticoagulant therapy.

For this reason, the Federal Institute for Risk Assessment also suggests one Maximum amount in food supplements of 80 µg K1 or 25 µg K2 per daily dose in front. Furthermore, the BfR recommends a warning on the packaging for food supplements with vitamin K, according to which people who take anticoagulant drugs (of the coumarin type) should consult their doctor before consuming food supplements containing vitamin K.

When taking anticoagulant medication, consume only after consulting a doctor

What does the body need vitamin K for?

"Vitamin K" does not mean a single vitamin, but a group of compounds with a similar basic structure.

The K vitamins are involved in the formation of various protein building blocks. For example, they are involved in the production of proteins for blood clotting and are important for proteins in blood plasma, kidneys and bones. This also explains the influence of vitamin K on the bone disease "osteoporosis". Studies have shown that women with low vitamin K intake are also at higher risk of fractures. What role the vitamin compounds actually play in the development of the disease and whether an additional intake of vitamin K is beneficial remains open. An influence on the protection of vitamin K on cardiovascular diseases is also discussed.

The amount of vitamin K a person needs can only be estimated, as there are no meaningful experimental studies. For this reason, the German Nutrition Society only gives vitamin K Estimates for adequate intake at.

  • At Men between 15 and 50 years of age this value is 70 µg; for men aged 51 and over, it is slightly more than 80 µg.
  • For Women the appropriate intake is estimated to be somewhat lower: girls and women between 15 and 50 years of age should take in around 60 µg, women from 51 years of age 65 µg.
  • For elderly people the value is approx. 10 percent higher in order to take into account a possibly higher need due to digestive disorders (see below) or medication intake.

A Vitamin K deficiency leads to blood clotting disorders. This visible and invisible bleeding can in turn cause dangerous damage in a wide variety of organs and organ systems - from the gastrointestinal tract to skin and mucous membranes to the adrenal gland, liver and brain. With the help of a single dose of vitamin K into the veins, it is possible to determine whether coagulation disorders are due to a vitamin K deficiency.

A diet-related Vitamin K deficiency does not occur in healthy people in Germany. If there is a vitamin K deficiency, this is often due to chronic gastrointestinal diseases such as celiac disease, fat digestion disorders, Chron disease or the so-called "short bowel syndrome". As a result, not enough vitamin K is absorbed. Chronic liver damage, on the other hand, can lead to insufficient utilization of vitamin K. Furthermore, deficiency symptoms are caused by long-term use of certain medications such as antibiotics, medication for epilepsy or tuberculosis, medication to inhibit blood coagulation and long-term use of salicylates, e.g. B. by aspirin, possible.

Can I cover my daily requirement with food?

The fat-soluble vitamin K compounds (K1 and K2) are absorbed into the small intestine cell with the help of special transport mechanisms. The uptake rate can fluctuate between 10% and 80%, as various factors increase or inhibit the uptake.

Vitamin K in its natural form is made by plants and microorganisms. The phylloquinone produced by plants, also known as vitamin K1, is found in large amounts in the chloroplasts of green plants. Even small amounts (30-100 g) of green vegetables such as kale, spinach and broccoli are enough to reach the estimated value for the appropriate intake.

Vitamin K can also be found in oils, pulses, fruits, grains and black tea. Vitamin K2 (Menaquinone), is absorbed through egg yolks, dairy products and meat. Because the farm animals take in vitamin K2 with their food. Vitamin K fluctuates in bacterially fermented foods such as cheese and yogurt2-Content, depending on the bacterial strain used. Vitamin K is rarely lost through food preparation, as the vitamin compounds in food are relatively stable to the effects of heat and oxygen. However, losses are possible when foods are stored for a long time due to the light sensitivity of the vitamin K compounds.

Certain bacteria in the human intestine are also able to produce vitamin K.2 to build. The significance in relation to meeting the needs is presumably minor, however, since the vitamin is formed in a section of the intestine in which fat-soluble vitamins are seldom absorbed.

Based on the nutrition survey from 1998 and the nutrition report of the German Nutrition Society from 2012, it can be assumed that enough vitamin K is consumed with food in Germany.

Since newborns do not yet have sufficient vitamin K stores, they are dependent on a rapid vitamin K supply after birth. The nutrition commission of the German Society for Child and Adolescent Medicine (DGKJ) therefore recommend giving vitamin K to prevent bleeding in infants. However, these are medicinal products and not dietary supplements. Oral administration of 2 mg vitamin K three times as drops is recommended. The first dose takes place immediately after the birth as part of the preventive medical check-up U1.

Our tip:
With a varied diet that includes plenty of green plants, you will get plenty of vitamin K and you don't have to worry about deficiency symptoms!


BfR (2021): Updated maximum quantity proposals for vitamins and minerals in food supplements and fortified foods
Opinion No. 009/2021 of March 15, 2021

BfR (2021): Maximum amount proposals for vitamin K in foods including dietary supplements

Vitamin K Intake and Health by Dr. Alexandra Schek published in Nutrition in Focus (BZfE) 05-06 2018, accessed May 29, 2020

Biesalski, H ../ Bischoff, S./Puchstein, C. (2010): Nutritional medicine, Georg Thieme Published by Stuttgart / New York.

German Nutrition Society, Austrian Nutrition Society, Swiss Nutrition Society (ed.) (2020): Vitamin K. In: Reference values ​​for nutrient intake, 2nd edition, 6th updated edition 2020, Köllen Druck + Verlag GmbH: Bonn

Network "Healthy in Life", accessed on May 29, 2020

Stahl, A./Heseker, H. (2011): Vitamin K: Physiology, Functions, Occurrence, Reference Values ​​and Supply in Germany, In: Ernahrung Umschau 3/11: 144-150

Vitamin K2 - the new "miracle vitamin" ?, Prof. Dr. rer. Nat. Martin Smollich, Deutsche Apotheker Zeitung, accessed on May 29, 2020

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