Diet

Vitamin K - a useful dietary supplement?

What is Vitamin K?

Vitamin K is basically a generic term for vitamins K1 and K2. It is fat-soluble and occurs as K1 (also phylloquinone) in vegetable foods and as K2 (also menaquinone) in animal foods.

In our body, vitamin K reaches the digestive tract together with fats, where it is bound by bile acids and then absorbed in the intestine. Vitamin K reaches the liver via our lymphatic system for storage. The vitamin is excreted in the urine and bile.

What is the role of vitamin K in the body?

On the one hand, vitamin K makes a significant contribution to blood clotting. In this context, it takes on a role as a coenzyme and helps in the production of coagulation factors that are required for the coagulation processes to take place at all - this ultimately helps to stop bleeding.

On the other hand, vitamin K is also significantly involved in bone metabolism. In this context, it participates in the synthesis of proteins in our bone cells. These are u. a. the calcium-binding proteins osteocalcin, MGP and protein S. Roughly speaking, vitamin K ensures that these proteins are activated and can then fulfill their functions. In this context, there are studies that indicate that a reduced vitamin K level and correspondingly high levels of uncarboxylated osteocalcin (the result of too little vitamin K) lead to an increased risk of bone fractures. However, this must first be adequately proven by further clinical studies.

Since vitamin K u. a. is related to the production of MGP, its importance for cardiovascular health is increasingly being discussed in research. In this context, the vitamin can possibly help prevent the calcification of tissues and vessels. At the current state of research, it can be said that vitamin K shows promise in terms of vascular calcification and the risk of developing coronary artery disease. However, the researchers are also calling for more and larger clinical studies to reliably confirm such observations.

How likely is a vitamin K deficiency?

In healthy people, a vitamin K deficiency is rather unlikely in this country - the need can simply be covered by diet. However, there are certain risk groups in which a vitamin K level that is too low can develop.

In this context, newborns should be mentioned first. These receive little vitamin K from the placenta and they also lack the intestinal bacteria that are capable of producing vitamin K. After birth and during the subsequent preventive medical check-ups, newborns therefore receive a vitamin K prophylaxis of 2 mg each as standard.

The production of vitamin K by intestinal bacteria can be disrupted if people take antibiotics for a long period of time.

Another drug intake that can be associated with a vitamin K deficiency concerns the so-called coumarins, also known as vitamin K antagonists. These inhibit the coagulation activity in the blood and prevent, for example, the development of thromboses. An exemplary active ingredient would be Marcumar. In this context, there is an “artificial” vitamin K deficiency.

Ultimately, various diseases can also affect the vitamin K balance, either by disrupting the absorption of the vitamin or by influencing the metabolism of the vitamin. These diseases include a .:

Crohn's disease, ulcerative colitis
Lipid metabolism disorders
chronic liver disease
Dysfunction of the bile
alcoholism
Celiac disease

What are the symptoms of vitamin K deficiency?

In general, a slight vitamin K deficiency manifests itself, for example, through tiredness and headaches. However, since vitamin K affects the coagulation system, a deficiency also promotes bleeding into tissue or generally increases the tendency to bleeding. Bleeding from the nose or gums is then more likely or a cut (e.g. when preparing food) bleeds longer than usual. Ultimately, a deficiency can also lead to an increased risk of bone fractures, as vitamin K influences the proteins that are responsible for calcium incorporation and, accordingly, bone density.

How much vitamin K do you have to consume daily and in which foods do you find vitamin K?

There are only estimated values for a daily intake of vitamin K. These vary depending on the age group and gender.

15–51 years → men: 70 µg / day; Women: 60 µg / day
from 51 years → men: 80 µg / day; Women: 65 µg / day
Pregnant & breastfeeding women → 60 µg / day

Vitamin K1 is mainly found in plant-based foods and there mostly in green vegetables such as B .:

Broccoli (270 µg / 100 g)
Kale (817 µg / 100 g)
Spinach (305 µg / 100 g)
Fennel (240 µg / 100 g)
Brussels sprouts (236 µg / 100 g)
Watercress (250 µg / 100 g)
Chives (380 µg / 100 g)

Vitamin K2, on the other hand, is found in foods of animal origin. a. in:

Milk and milkproducts)
egg yolk
flesh

Vitamin K is considered to be relatively heat-resistant. This means that the vitamin K content is retained even when food is prepared. However, this decreases when food is stored for a long time.

Can I safely take vitamin K as a dietary supplement?

Vitamin K cannot be safely taken as a dietary supplement. Because, as already mentioned, vitamin K can interact with common anti-coagulants such as Marcumar. Even small amounts of additionally supplied vitamin K can reduce the success of the therapy with the anticoagulants. So it is very important that you consult with your doctor before you plan to take vitamin K supplements.

Once that has been clarified, the question still remains whether supplementation makes sense. The answer to that is a resounding “yes and no”. Because whether vitamin K really helps as a dietary supplement depends on your condition. If you have another illness, e.g. For example, if you suffer from a vitamin K deficiency, it can make perfect sense to use an appropriate dietary supplement - that is, in a therapeutic sense. But here, too, the doctor decides to what extent a change in diet with increased vitamin K intake might be sufficient.

Generally speaking, people on a balanced diet shouldn't need vitamin K supplementation. With this in mind, if you still want to take a vitamin K food supplement, you should not exceed 80 µg per day.