Vitamin K1 vs K2
Vitamin K1 vs K2
Vitamin K1 vs K2: What's the Difference?Vitamin K1 (phylloquinone) and vitamin K2 (menaquinones) are two forms of the same fat-soluble vitamin with distinct roles. K1 is abundant in leafy greens and is primarily used by the liver to activate clotting factors, supporting normal blood coagulation. K2, especially the MK-7 subtype from fermented foods, has a longer half-life and is preferentially delivered to bone and arteries, where it activates proteins like osteocalcin and matrix Gla protein. These differences mean K1 is essential for coagulation, while K2 appears more effective for bone and cardiovascular health.Bone & Heart Health BenefitsWhile both forms activate vitamin K-dependent proteins, research suggests K2 is more efficient at supporting bone mineralization and preventing arterial calcification. Observational studies link higher K2 intake with lower coronary heart disease risk, whereas K1 shows less association. For postmenopausal women and older adults, sufficient K2 intake may help maintain bone density and arterial flexibility. Vitamin D and K2 also work together: vitamin D increases calcium absorption, and K2 helps direct that calcium to bones rather than arteries.Choosing the Right Form & DosageFor general health, a diet rich in leafy greens provides ample K1. To cover the K2 gap, include natto, aged cheese, egg yolks, or consider an MK-7 supplement at 45–90 mcg daily. MK-7 has a 72-hour half-life, allowing once-daily dosing, while MK-4 requires multiple doses. People on anticoagulants like warfarin should maintain consistent K1 intake and consult a healthcare provider before taking K2, as it may affect INR. Always choose a supplement with fat for better absorption.