Vitamin K is a fat soluble vitamin. The fitoquinona, natural form of vitamin K found in alfalfa and other foods, was discovered in Denmark and designated as vitamin K for the Danish word koagulation.
Phylloquinone providing food is designated as K1, while menaquinone produced by our intestinal bacteria called vitamin K2. A synthetic compound with the basic structure of the quinones is menadione or vitamin K3.
Vitamin K is important for proper blood clotting in humans. It is essential for synthesis in the liver of four coagulation proteins.