What are K vitamins?

K vitamins are a group of fat-soluble vitamins. The two most important forms found in food are vitamin K1 (phylloquinone) and vitamin K2 (menaquinone). Vitamin K1 is known for its role in blood coagulation (clotting), while vitamin K2 is a new form of vitamin K which is important also for building and maintaining strong bones, as well as inhibiting calcium deposits in the arteries. Supplemental vitamin K2 exists in several forms and the most common ones are the synthetic menaquinone-4 (MK-4) and the natu­ral menaquinone-7 (MK-7).