Vitamin K₂ (menaquinone-7) promotes healthy vascular calcium balance and cardiovascular function. In a systematic review involving fivestudies, 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, menaquinone-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), an anticoagulant medication.