What is the difference between Vit K1 (Vitamin K1) and Vit K2 (Vitamin K2) in terms of supplementation and dosage?

Vitamin K1 vs Vitamin K2: Supplementation and Dosage Differences

Vitamin K1 (phylloquinone) and Vitamin K2 (menaquinones) have distinct roles in human health, with Vitamin K1 primarily supporting blood clotting while Vitamin K2 shows greater benefits for bone and cardiovascular health. 1

Key Differences Between Vitamin K1 and K2

Sources and Bioavailability

• Vitamin K1 (Phylloquinone)

  • Primary dietary sources: leafy greens, cruciferous vegetables, asparagus, prunes, peas, and parsley 2
  • Shorter half-life compared to K2
  • Lower bioavailability

• Vitamin K2 (Menaquinones)

  • Produced by intestinal bacteria (including E. coli) 2
  • Found in fermented foods and animal products
  • Longer half-life, allowing for more stable blood levels
  • Better extrahepatic activity (activity outside the liver) 3

Physiological Functions

Vitamin K1:

• Primary role in blood coagulation
• Primarily utilized by the liver for clotting factor activation
• Used medically to reverse warfarin-related coagulopathy 4

Vitamin K2:

• More effective for bone health through osteocalcin carboxylation 5
• Superior for cardiovascular health by preventing vascular calcification 1
• Shows promising effects in diabetes, cancer, and osteoarthritis 1
• Better activity in extrahepatic tissues 3

Supplementation Guidelines

Recommended Dosages

Vitamin K1:

• Adequate Intake (AI): 1 mg/kg body weight per day according to EFSA
• Adult males: 120 μg daily
• Adult females: 90 μg daily 2
• For warfarin reversal: 2.5-10 mg initially, up to 25 mg (rarely 50 mg) 4

Vitamin K2:

• No specific RDI established yet, though evidence suggests it should have its own recommendation separate from K1 3
• For bone health: Higher doses have been used in studies (often in the range of 45-360 μg daily) 1
• For cardiovascular health: Evidence supports supplementation but optimal dosage not firmly established 1

Clinical Applications

Bone Health

• Vitamin K2 has demonstrated superior effects on bone mineral density and fracture reduction compared to K1 5
• Works synergistically with vitamin D for bone health 5
• May rival bisphosphonate therapy for osteoporosis without toxicity 1

Cardiovascular Health

• Vitamin K2 significantly reduces vascular calcification and cardiovascular disease risk 1
• Dephosphorylated uncarboxylated matrix Gla protein (dp-ucMGP) levels decrease with K2 supplementation 6

Special Populations

• Dialysis patients: Severe vitamin K deficiency is common, with K2 supplementation showing promise for reducing vascular calcification 6
• Patients on warfarin: While K1 is traditionally used for reversal, K2 has also been used effectively in some countries like Japan 7

Important Considerations

• Vitamin K supplements may interact with anticoagulant medications like warfarin
• For patients on vitamin K antagonists, continuous enteral nutrition should be withheld for 1 hour before and after anticoagulant administration 2
• Vitamin K1 and K2 are not associated with toxicity, unlike synthetic vitamin K3 which can cause serious adverse effects 2
• When supplementing, consider that intestinal bacteria contribute to vitamin K2 production, which may be disrupted by antibiotics 2

Monitoring

• No single biomarker adequately assesses vitamin K status 6
• For cardiovascular endpoints, dephosphorylated uncarboxylated matrix Gla protein (dp-ucMGP) is the best biomarker for vascular vitamin K status 6
• For general vitamin K1 status, plasma concentrations <0.15 mg/L indicate deficiency 2

In clinical practice, the choice between K1 and K2 should be guided by the specific health concern being addressed, with K1 being more appropriate for coagulation issues and K2 being superior for bone and cardiovascular health.