Vitamin K2: what is it and what is it good for?
What is vitamin K2?
Vitamin K is a fat-soluble vitamin and its name comes from the Danish term Koagulations Vitamin, given to the nutrient by the Danish researcher Hendrik Dam. Coagulation is another word for blood clotting. At the beginning of the last century, Hendrik Dam discovered that vitamin K has a blood-clotting effect in our bodies. Only fairly recently has scientific research shown that vitamin K is important for much more in the body. It helps maintain strong bones by supporting the absorption of calcium into bone tissue. This particularly concerns the well-absorbed form, vitamin K2.
What is the difference between vitamin K1 and vitamin K2?
Vitamin K can be divided into K1 (e.g. phytomenadione) and K2 (menaquinone). Vitamin K1 is difficult for our bodies to absorb, unlike vitamin K2. Even so, we mainly consume a lot of vitamin K1 through the Western diet, as it is found in various types of (mainly) green vegetables. The highest amounts of vitamin K1 are found in:
- Swiss chard 830 mcg per 100 grams
- kale 623 mcg per 100 grams
- spinach 394 mcg per 100 grams
It is also found in endive, cabbage and broccoli, as well as, for example, green tea. A small proportion of vitamin K1 intake can be converted by the body into vitamin K2. Around 90% of our vitamin K intake is vitamin K1 and only 10% is vitamin K2, so it is important to ensure you also get enough vitamin K2.
Vitamin K2
Vitamin K2 is indicated as MK (menaquinone) and can be divided into different variants: MK4, MK6, MK7, MK8 and MK9. Within the vitamin K2 family, MK7 is the most readily absorbed by the body. That is why the MK7 variant is used in food supplements for vitamin K2 supplementation. Vitamin K2 is produced by certain bacteria and is mainly found in small amounts in fermented foods such as quark, yoghurt and cheese. It is also present to a limited extent in meat and eggs. One of the best-known and richest sources of vitamin K2 is Japanese natto: fermented soya beans containing around 1,000 mcg of K2 per 100 grams! By comparison, cheese contains around 10 mcg of K2 per 100 grams. As well as being a rich source, natto also contains the MK7 variant, which research1 shows has the highest bioavailability. Natto is therefore often used as a natural source from which vitamin K2 is extracted for food supplements.
Synergy with vitamin D3
An important vitamin that works closely with vitamin K2 is vitamin D3, which contributes to the absorption of calcium and phosphorus from the diet and therefore also supports normal bone strength. When taking vitamin D3, it is recommended to supplement with extra vitamin K2 because of the synergy between these two vitamins. There are supplements that provide both vitamins in one capsule, such as Vitaminstore’s Super K2.
Author: Noëlle van Seggelen
