Vitamin K
Vitamin K exists as vitamin K1 (phylloquinone) and vitamin K2 (menaquinone). Phylloquinone is mainly found in plants, while the more active menaquinone is produced by gut bacteria and is also found in fermented foods such as sauerkraut and the Japanese fermented soybean dish nattō.
Vitamin K2
Vitamin K2 activates a series of special proteins which play a role in important metabolic processes, including blood clotting as well as calcium transportation and utilisation. Most organisations do not consider vitamin K1 and K2 separately and, as such, there is limited information on the benefits of vitamin K2 specifically.
According to the European Food Safety Authority (EFSA), vitamin K contributes to:
- Normal blood clotting
- The maintenance of normal bones
Vitamin K2 and Vitamin D
Vitamin D and vitamin K2 both play key roles in calcium metabolism. Together, they regulate the cells which form and break down bones as well as the important transport molecules which ensure the correct utilisation of calcium.