Vitamin K – important for blood, bones and vessels

What is vitamin K2?

Vitamin K2, also known as menaquinone, is a fat‑soluble vitamin that belongs to the family of vitamins playing a crucial role in blood clotting as well as bone formation and calcium binding. Vitamin K2 is one of the two main forms of vitamin K. It exists alongside vitamin K1, which is found in green leafy vegetables.

The name for vitamin K2 is menaquinone and it is abbreviated as MK. There are several forms, including MK‑4, MK‑7, MK‑8 and MK‑9, the number after "MK" indicating the length of the side chain in the molecule. According to current scientific knowledge, menaquinone‑7 (MK‑7) is considered the most effective form of vitamin K2. MK‑7’s high efficacy is based on its excellent absorption (bioavailability) and its long half‑life, allowing it to remain in the body for a longer period and exert its effect. There are both natural and synthetic forms of MK‑7, also referred to as "isomers". However, only the natural isomer (the "trans" form) is active and effective in the body.

Where is vitamin K2 found?

Vitamin K2 is present in varying amounts in a normal diet. Three food sources of K2 are preferable:

• Eel, known for its high energy and nutritional value, has a good vitamin K2 content of 0.5 µg per 100 grams.
• Nattō, a traditional Japanese fermented food made from fermented soybeans, is most commonly eaten in Japanese cuisine as a side dish to plain rice. With an equivalent of 150 µg for one tablespoon of nattō, it is an important source of vitamin K2.
• Cheese is also a natural source of menaquinone (vitamin K2). The origin of the cheese and its quality influence the vitamin K2 content. Raclette cheese is, for example, the cheese with the highest vitamin K2 content.

What are the benefits of vitamin K2?

Vitamin K contributes to normal blood clotting

Vitamin K2 indirectly contributes to normal blood clotting by playing a crucial role in activating certain proteins that are necessary for blood clotting. These proteins are known as clotting factors, and vitamin K2 is required to convert them into their active form. The main clotting factors activated by vitamin K2 are factor II (also known as prothrombin), factor VII, factor IX and factor X. These factors are essential for the process of blood clotting, which serves to stop bleeding after injuries. Vitamin K2 enables the conversion of these clotting factors from their inactive precursors into their active forms. This occurs through a chemical modification in which certain amino acids in the proteins are altered so that they can participate in blood clotting.

Vitamin K contributes to the maintenance of normal bones

Vitamin K contributes to the maintenance of normal bones because it plays a crucial role in bone metabolism. It works in conjunction with other nutrients such as calcium and vitamin D to support bone health. Here are the main reasons why vitamin K is important for bones:

• Bone formation: Vitamin K is necessary for the synthesis of osteocalcin, a protein that is incorporated into the bone matrix. Osteocalcin helps to incorporate calcium into the bones and thus contributes to their strength and structure.
• Calcium regulation: Vitamin K plays a role in regulating calcium metabolism in the body. It promotes the uptake of calcium into the bones while preventing calcium from being deposited in the arteries and tissues, which could lead to calcification.