Vitamin K is a group of fat soluble vitamins that play an essential role in normal physiological processes in the body, including blood clotting and the regulation of calcium.
The term “vitamin K” comes from the German word Koagulation, reflecting its role in helping blood clot normally.
There are two main forms of vitamin K: vitamin K1 (phylloquinone) and vitamin K2 (menaquinones). While both are important, they differ in their sources, absorption and functions within the body.
Vitamin K1 vs Vitamin K2
Vitamin K1 (Phylloquinone)
Vitamin K1 is found primarily in green leafy vegetables such as spinach, kale and broccoli. It is mainly involved in supporting normal blood coagulation.
Vitamin K2 (Menaquinones)
Vitamin K2 refers to a group of compounds known as menaquinones (MK-4 to MK-13). One of the most studied forms is MK-7, which has greater bioavailability and remains in the body for longer.
Although some vitamin K1 can be converted into K2 by gut bacteria, this process is limited and varies between individuals.
What Does Vitamin K2 Do?
Role in Calcium Regulation
Vitamin K2 contributes to the activation of vitamin K dependent proteins involved in the regulation and utilisation of calcium in the body.
Bone Health
Vitamin K2 plays a role in bone mineralisation and is involved in maintaining normal bone structure.
Cardiovascular System and Blood Vessel Health
Vitamin K2 is involved in processes that contribute to maintaining blood vessel health and supporting cardiovascular system function as part of general wellbeing.
Vitamin K2 and Research
Vitamin K2 has been the subject of growing scientific interest, particularly in relation to bone and cardiovascular health.
Some observational studies have explored associations between dietary vitamin K2 intake and various health outcomes. However, these findings do not establish cause and effect and should be interpreted alongside overall diet and lifestyle factors.
Clinical research has also investigated vitamin K2 in relation to bone and vascular health markers, though further research is needed to better understand these relationships.
Dietary Sources of Vitamin K2
Vitamin K2 is found mainly in animal based and fermented foods.
Natto (Fermented Soybeans)
Natto is one of the richest dietary sources of vitamin K2, particularly in the MK-7 form.
Cheese
Fermented cheeses such as Gouda and Brie contain vitamin K2 due to bacterial activity during production.
Egg Yolks
Egg yolks provide moderate amounts of vitamin K2 and can contribute to dietary intake.
Grass Fed Meat and Butter
Animal products from grass fed sources may contain small amounts of vitamin K2.
Other Fermented Foods
Foods such as sauerkraut and kefir may contain variable levels of vitamin K2 depending on fermentation methods.
Vitamin K2 Intake and Diet
Dietary intake of vitamin K2 can vary depending on food choices and individual factors such as gut health.
Including a variety of vitamin K2 containing foods may help support adequate intake as part of a balanced diet.
Key Takeaways
- Vitamin K2 is a fat soluble vitamin involved in calcium regulation in the body
- It plays a role in bone health and normal physiological function
- It contributes to maintaining blood vessel health and cardiovascular system function
- Food sources include fermented foods and animal products
- Intake can vary depending on diet and lifestyle
Important Considerations
If you are taking anticoagulant medication or have a medical condition, seek advice from a healthcare professional before making changes to vitamin K intake.
This information is general in nature and is not intended to replace advice from your healthcare professional. Always read the label and follow direcitons for use.
References
- NIH Office of Dietary Supplements. Vitamin K Fact Sheet
- EFSA Panel on Dietetic Products. Dietary reference values for vitamin K
- Booth SL. Roles for vitamin K beyond coagulation. Annual Review of Nutrition
- Walther B et al. Menaquinones in food. Advances in Nutrition
- Schurgers LJ et al. Vitamin K metabolism and bioavailability. Blood
- Beulens JWJ et al. Dietary vitamin K intake and health outcomes
