Insufficient vitamin K2 is associated with low bone density and fracture risk. Vitamin K is the name given to a group of similar compounds, but the “rising star” is vitamin K2, which, with vitamin D and A, plays an essential role in a chain of events that determine how and where the body uses calcium. Webber naturals features vitamin K2 as menaquinone-7 (MK7), a natural bioactive form derived from natto (fermented soybean).