Vitamin K

Carola Felchner is a freelance writer in the medical department and a certified training and nutrition advisor. She worked for various specialist magazines and online portals before becoming a freelance journalist in 2015. Before starting her internship, she studied translation and interpreting in Kempten and Munich.

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The term vitamin K includes vitamin K1 (phylloquinone) and vitamin K2 (menaquinone). Like vitamins A, D and E, vitamin K is fat soluble. It is especially important for blood clotting. Find out here how much vitamin K you need and what tasks it performs.

What is Vitamin K?

Vitamin K is one of the fat-soluble vitamins (like vitamins A, D and E). It occurs naturally as vitamin K 1 (phylloquinone) and vitamin K 2 (menaquinone). Phylloquinone is mainly found in green plants. Menaquinone is produced by bacteria such as E. coli, which are also found in the human intestine. Apparently, K2 is the more active form of the vitamin. However, the effect is the same for both.

Vitamin K is absorbed in the intestine and transported via the blood to the liver, where it fulfills its main task - the production of blood clotting factors.

In addition to the natural compounds vitamin K1 and K2, there is also the synthetic vitamin K3 (menadione). It was previously used to treat vitamin K deficiency, but is no longer approved - due to its side effects: Among other things, vitamin K3 can damage the liver and cause anemia due to the breakdown of red blood cells (hemolytic anemia).

What are the tasks of vitamin K in the body?

Blood coagulation is the most important task of vitamin K: It is required for the formation of coagulation factors from inactive precursors. Without vitamin K, the body cannot produce these factors and thus cannot stop bleeding.

Other effects of vitamin K: It prevents calcium deposits in soft tissues such as blood vessels and cartilage. It also helps regulate cell processes (such as cell division) and repair processes in the eyes, kidneys, liver, blood vessels and nerve cells. In addition, vitamin K inhibits bone loss in postmenopausal women - the enzyme osteocalcin, which regulates bone mineralization, is vitamin K-dependent.

Vitamin K antagonists as a drug

The important role of vitamin K in blood clotting has been used for decades to reduce blood clotting in certain diseases. This is necessary in patients who are prone to the formation of blood clots (for example due to atrial fibrillation or artificial heart valves). They are often treated with drugs that block the effects of vitamin K - so-called vitamin K antagonists. The preparations prevent vitamin K from converting the precursors of the blood clotting factors into their active form. This will reduce the risk of the blood clotting and blood clots forming.

What is the daily requirement of vitamin K?

How much vitamin K you need daily varies from person to person. According to the German Nutrition Society (DGE), the recommended daily amount for adolescents from 15 years of age and adults, depending on age and gender, is between 60 and 80 micrograms of vitamin K. Babies in the first year of life have a daily vitamin K requirement of 4 to 10 micrograms, Children have a daily requirement between 15 and 50 micrograms, depending on their age.

This is how much vitamin K you need according to the DGE:

	Vitamin K daily requirement in µg / day
Baby*
0 to under 4 months	4
4 to less than 12 months	10
children
1 to under 4 years	15
4 to under 7 years	20
7 to under 10 years	30
10 to under 13 years	40
13 to under 15 years	50
Adolescents / adults	masculine	Female
15 to under 19 years	70	60
19 to under 25 years	70	60
25 to under 51 years	70	60
51 to under 65 years	80	65
65 years and older	80	65
Pregnant women		60
Breastfeeding		60

* Newborns get vitamin K through breast milk. However, since this is not enough to fill the reservoirs adequately, all infants are given additional vitamin K by the pediatrician during the first preventive medical check-ups after birth.

In the case of certain diseases (increased risk of vascular occlusion due to blood clots = thrombosis), the doctor can recommend a reduced vitamin K intake.

Vitamin K: foods with a high content

Read more about vitamin K values ​​in foods in the article Foods with a high vitamin K content

How does a vitamin K deficiency manifest itself?

Inadequate dietary intake is rare. Nutritionists assume that you get more than enough vitamin K with a mixed diet.

When the vitamin K level drops, the body apparently uses the vitamin K produced by intestinal bacteria. If there is still a proven vitamin K deficiency (for example in the case of chronic kidney weakness), there is a tendency to bleed. Because of the vitamin K deficiency, the vitamin K-dependent blood coagulation factors are no longer sufficiently produced - the blood coagulates more poorly.

The doctor can determine the INR value or Quick value to check how well a patient's blood clotting is working.

How does a vitamin K excess manifest itself?

According to the current state of knowledge, healthy adults are not at risk of harm from a diet with excessive amounts of vitamin K. Newborns, on the other hand, can be dangerous with an excess of vitamin K: It can trigger the breakdown of red blood cells (hemolysis).

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