New research is focusing on the synergistic relationship between vitamin K2 and vitamin D3, for bone and cardiovascular health. A group of naturally occurring and structurally similar, fat-soluble vitamins, vitamin K is essential for the proper utilization of calcium. Through its activation of the protein osteocalcin, vitamin K helps to bind newly absorbed calcium to the mineral matrix in bone. In addition, vitamin K has been found to help maintain bone mineral density by decreasing the activity of osteoclasts, a cell that breaks down the bone matrix. Vitamin K also provides critical cardiovascular protection by helping to activate matrix Gla protein (MGP), an inhibitor of circulatory calcification. Thus, vitamin K and vitamin D not only share similar qualities, but they also act synergistically within the body.