Episode 7: Why You Should Be Taking Vitamin K2 

Host: Dr. Ravi Kumar MD

Topic: A comprehensive look at vitamin K2’s discovery, mechanisms, clinical evidence, and why it’s essential for calcium homeostasis, bone strength, and vascular health. 

📖 Episode Overview 

• Historical journey from Weston A. Price’s “Activator X” to the Nobel‐winning discovery of vitamin K
• Biochemical roles of K1 vs. K2: activating clotting factors vs. directing calcium into bones and out of arteries
• Ancestral dietary patterns that once guaranteed year-round vitamin K2 intake
• Key clinical findings on bone mineral density, fracture risk, arterial calcification, and beyond
• Drug interactions: how warfarin and statins inadvertently disrupt K2 pathways
• Supplementation strategy: MK-7 vs. MK-4, practical dosing, and Dr. Kumar’s personal protocol
• Next episode teaser on omega-3 fatty acids

✨ Key Takeaways

• Vitamin K2 (menaquinones) is indispensable for proper calcium placement—bones vs. arteries.
• Traditional diets provided K2 via seasonal greens and fermented foods; modern diets are often deficient.
• Meta-analyses and RCTs demonstrate up to 57% fewer fractures and slower arterial calcification with K2.
• MK-7 (180–375 µg/day) offers superior bioavailability and tissue delivery compared to MK-4.
• Pair K2 with vitamin D and dietary fat for optimal absorption.

📚 References & Study Summaries

1. Dietary Intake of Menaquinone Is Associated with a Reduced Risk of Coronary Heart Disease in Older Men and Women
   • Prospective cohort of older adults showing that higher dietary menaquinone (vitamin K2) intake was linked to a significant reduction in coronary heart disease incidence.
   • ScienceDirect
2. Vitamin K2 Ameliorates Osteoarthritis by Suppressing Ferroptosis and Extracellular Matrix Degradation Through Activation of GPX4
   • Preclinical rodent study demonstrating that MK-7 improves cartilage integrity, reduces pain scores, and lowers osteoarthritis severity by inhibiting ferroptosis and activating the antioxidant enzyme GPX4.
   • ScienceDirect
3. Multiple Dietary Vitamin K Forms Are Converted to Tissue MK-4 in Mice
   • Animal feeding trial revealing that dietary phylloquinone (K1) and various menaquinones (MK-4, MK-7, MK-9) all serve as precursors for tissue MK-4, highlighting a common conversion pathway across tissues.
   • ScienceDirect
4. Role of Menaquinone-7 in Bone Health: A Comprehensive Review
   • Systematic review in Frontiers in Nutrition summarizing mechanistic and clinical evidence for MK-7’s effectiveness in enhancing bone mineral density, reducing fracture risk, and exhibiting an excellent safety profile.
   • Frontiers in Nutrition
5. Effect of Vitamin K2 on Bone Mineral Density and Fracture Risk in Postmenopausal Women
   • Meta-analysis of RCTs involving over 6,400 participants, showing that VK2 supplementation (primarily MK-4 and MK-7) significantly improved lumbar spine BMD and lowered overall fracture risk by approximately 57%.
   • PubMed
6. Vitamin K Status in Chronic Kidney Disease and Hemodialysis Patients
   • Observational study reporting elevated levels of undercarboxylated vitamin K-dependent proteins (dp-ucMGP, ucOC) in CKD and dialysis cohorts, indicating widespread subclinical K deficiency in these populations.
   • PMC
7. Dietary Vitamin K Intake and Bone Health in Public-Health Populations
   • Population-level analysis linking higher dietary vitamin K intake to reduced osteoporosis prevalence and fewer fractures among older adults, reinforcing the public-health importance of K.
   • Frontiers in Public Health
8. High-Dose MK-7 Supplementation and Vascular Calcification Markers
   • Double-blind RCT (360 µg MK-7/day for 3 months) demonstrating marked reductions in dp-ucMGP—a biomarker of vascular calcification risk—in healthy volunteers.
   • PubMed
9. Long-Term MK-4 Therapy Prevents Vertebral Fractures in Osteoporotic Women
   • Clinical trial showing that 45 mg/day MK-4 over 3 years significantly lowered the incidence of new vertebral fractures compared to control, despite pharmacologic dosing far above dietary levels.
   • PubMed
10. Comparative Pharmacokinetics of MK-7 vs. MK-4 in Humans
    • Pharmacokinetic study revealing that MK-7 has a substantially longer half-life and higher steady-state blood levels than MK-4 when administered orally, supporting MK-7’s use in supplementation.
    • PubMed
11. Effect of Low-Dose MK-7 on Osteocalcin Carboxylation
    • Controlled trial finding that 180 µg/day of MK-7 for 12 weeks significantly increased the ratio of carboxylated to undercarboxylated osteocalcin, indicating enhanced bone-matrix protein activation.
    • PubMed
12. Regional Differences in Vitamin K2 Biomarkers and Bone Health
    • Cross-sectional study of Japanese adults correlating serum K2 levels (MK-7) with superior bone density measures and lower fracture prevalence across regions with habitual natto consumption.
    • SpringerLink
13. Traditional Dietary Sources of Vitamin K2 in Japanese Communities
    • Ethnographic dietary survey documenting seasonal consumption of natto, fermented vegetables, and dairy in rural Japanese villages, with measured K2 intakes averaging >300 µg/day.
    • Kindai University PDF
14. Effects of Combined Vitamin K2 and D3 on Coronary and Aortic Calcification
    • Multicenter RCT (720 µg K2 + 25 µg D3/day vs. placebo) in elderly subjects, reporting a nonsignificant trend toward slower CAC progression overall but significant benefit in participants with baseline CAC ≥400 AU.
    • ScienceDirect
15. MK-7 Supplementation in Hemodialysis Patients
    • RCT administering 1,080 µg MK-7 three times weekly to dialysis patients for 12 weeks, which normalized dp-ucMGP levels by 86% without adverse events.