What is vitamin K?
Vitamin K is one of the fat-soluble vitamins (like vitamins A, D and E). It occurs in nature 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 used to be 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 functions does vitamin K have in the body?
Other effects of vitamin K: It prevents calcium deposits in soft tissues such as blood vessels and cartilage. It also helps to regulate cell processes (such as cell division) and repair processes in the eyes, kidneys, liver, blood vessels and nerve cells. Vitamin K also inhibits bone loss in women after the menopause – the enzyme osteocalcin, which regulates bone mineralization, is vitamin K-dependent.
Vitamin K antagonists as medication
What is the daily requirement for vitamin K?
How much vitamin K you need each day varies from person to person. According to experts, the recommended daily amount for adolescents aged 15 and over and adults is between 60 and 80 micrograms of vitamin K, depending on age and gender. Babies in their first year of life have a daily vitamin K requirement of 4 to 10 micrograms, while children have a daily requirement of between 15 and 50 micrograms, depending on their age.
The German, Austrian and Swiss Nutrition Societies have developed (DACH) reference values that are considered appropriate and well tolerated:
|
Vitamin K daily requirement in µg/day |
||
|
Infants* |
||
|
0 to under 4 months |
4 |
|
|
4 to under 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 |
|
|
Teenagers / Adults |
male |
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 |
In the case of certain diseases (increased risk of vascular occlusion due to blood clots = thrombosis), the doctor may recommend a reduced vitamin K intake.
Vitamin K: Foods with a high content
Read more about vitamin K levels in foods in the article Foods with a high vitamin K content
How does a vitamin K deficiency manifest itself?
Inadequate intake through food is rare. Nutritionists assume that you get more than enough vitamin K from a mixed diet.
If the vitamin K level drops, the body apparently uses the vitamin K produced by intestinal bacteria. If there is nevertheless a proven vitamin K deficiency (e.g. in the case of chronic kidney failure), there is a tendency to bleed. This is because the vitamin K deficiency means that the vitamin K-dependent blood clotting factors are no longer produced in sufficient quantities – the blood clots more poorly.
To check how well a patient’s blood clotting works, the doctor can determine the INR value or Quick value.
