Vitamin K2 is a key regulator of clinically relevant molecular processes

Vitamin K denotes a group of lipophilic vitamins determining posttranslational modification of proteins. There are two main forms of vitamin K: vitamin K1 (phylloquinone, PK, found in vegetables), and vitamin K2 (menaquinone, MKn, produced by bacteria in the intestine and in fermented foods). Vitamin K1 is principally transported to the liver, regulating the production of coagulation factors. Vitamin K2 is transported to extrahepatic tissues, such as bone and arteries. When considering the issue of adequate vitamin K intake in the general population and in patients affected by bone and mineral abnormalities, specifically osteoporosis and cardiovascular calcification, the distinction between PK and MKn is often underestimated. Although the two forms of vitamin K have similar activity in sustaining the vitamin K cycle and the carboxylation of vitamin K–dependent proteins, their role may be markedly different and therefore their use for the prevention and treatment of bone and mineral abnormalities could follow different pathways and require different doses. We explain in this article that vitamin K2 is a key regulator of clinically relevant molecular processes and propose that its use as a dietary supplement and as a pharmacological treatment for bone and mineral abnormalities should be further explored.