Vitamin K

Vitamin K is a fat-soluble vitamin that occurs naturally in different forms: As K1, it is mainly found in green vegetables such as spinach, lamb's lettuce and broccoli. Other sources of K1 are vegetable fats and oils. As K2, on the other hand, the vitamin is found in animal-source foods, e.g., liver, dairy products and eggs.

Vitamin K is involved in the formation of blood clotting factors. In addition, vitamin K together with some other micronutrients (e.g. calcium, phosphorus, vitamin D) is important for bone health.  

Newborns and breastfed infants are a special risk group for vitamin K deficiency, since vitamin K reaches the child only insufficiently via the placenta and breast milk contains only little of it. In the first weeks of life, an undersupply of the fat-soluble vitamin can lead to life-threatening haemorrhages. For this reason, all newborns in Germany receive preventive vitamin K shortly after birth as part of the U1 screening examination and at the second and third screening examinations - between the 3rd and 10th day of life (U2) and between the 4th and 5th week of life (U3).

At present, there are no other indications that the population in Germany consumes too little vitamin K or that it is inadequately supplied with vitamin K.

Vitamin K is often added to food supplements. It should be noted that such an additional intake of vitamin K can weaken the therapeutic effect of anticoagulant drugs (anticoagulants of the coumarin type = vitamin K antagonists). In Germany, many older people take such drugs for thrombosis prophylaxis. Those who do so should keep their vitamin K intake through diet as constant as possible and only take vitamin K-containing food supplements under medical supervision.

In order to provide consumers with significant additional nutrient intake via food supplements when needed and at the same time protect well-supplied people from excessive intake, the German Federal Institute for Risk Assessment (BfRshort forGerman Federal Institute for Risk Assessment) recommends not adding more than 80 micrograms (µgshort formicrogram) of vitamin K1 or no more than 25 µgshort formicrogram of vitamin K2 per daily dose to a food supplement. Furthermore, the BfRshort forGerman Federal Institute for Risk Assessment recommends a note on food supplements containing vitamin K stating that people taking anticoagulant medicines (of the coumarin type) should seek medical advice before consuming food supplements containing vitamin K.

* People taking anticoagulant drugs should seek medical advice before taking any food supplements that contain vitamin K

Status: 07/11/2023