Vitamin K2 menaquinone-7 (MK-7) promotes healthy vascular calcium balance and cardiovascular function. In a systematic review involving 5 studies, higher intakes of vitamin K2 were associated with cardiovascular health. Research indicates that it supports the carboxylation of matrix Gla-protein (MGP), a key protein involved in calcium balance. Unlike vitamin K1, which promotes bone health, MK-7 targets vascular tissue to support healthy arterial blood flow and vascular elasticity. In an observational study involving 564 postmenopausal women, higher intake of vitamin K2 was associated with calcium balance in the vascular tissue. Optimal serum levels of vitamin D are also important to maintain healthy calcium balance in vascular tissues, in part by supporting the activity of MGP. Studies indicate that the combination of vitamin K and D provides synergistic support. Vitamin K supplementation may be contraindicated for those taking Coumadin/warfarin anticoagulant medication.