🧬 Family & Essentiality

🌿 Plain-Language Summary

Vitamin K1 supports normal blood coagulation and contributes to activation of vitamin K-dependent proteins. It is abundant in leafy green vegetables and some plant oils.

⚗️ Molecular & Chemical IDs

• Phylloquinone (K1): C₃₁H₄₆O₂ (CAS 84-80-0)
• Solubility/Transport: Fat-soluble; absorbed with dietary fat and transported in chylomicrons
• Storage: Primarily in the liver; faster turnover than other fat-soluble vitamins

⚡ Functions

• Enables γ-carboxylation (activation) of coagulation factors II, VII, IX, X and proteins C & S
• Supports activation of Gla-proteins (e.g., osteocalcin involved in bone physiology)

🍽️ Absorption & Bioavailability

🇦🇺 Australian NRVs (NHMRC) — Adequate Intake

• Adult men: 70 µg/day
• Adult women: 60 µg/day
• Pregnancy: 60 µg/day
• Lactation: 60 µg/day

Upper Level (UL): Not established for K1.

🚨 Deficiency & Excess

Deficiency

Easy bruising, prolonged clotting; in newborns, vitamin K deficiency bleeding (prevented with neonatal K1).

Excess

No adverse effects reported from food forms. Use caution with very high supplemental doses, particularly for people on anticoagulant therapy.

🥗 Food Sources

• Leafy greens: kale, spinach, silverbeet, parsley
• Crucifers: broccoli, Brussels sprouts
• Plant oils: soybean, canola
• Herbs: basil, coriander

💡 Tip: Pair greens with olive or canola oil to enhance K1 absorption.

🧪 Testing & Monitoring

• No routine population screening for K1 status
• Clinical markers: Prothrombin time/INR; PIVKA-II (Protein Induced by Vitamin K Absence/Antagonism-II) as a functional marker
• Consider assessment in fat-malabsorption, prolonged antibiotic use, or anticoagulant therapy

🔗 Interactions

• Warfarin / VKAs: Dietary K1 consistency is important — follow medical guidance
• Broad-spectrum antibiotics may reduce bacterial vitamin K production, affecting status
• Bile acid sequestrants and orlistat may reduce absorption

🆚 K1 vs K2 (Scope Note)

📊 Evidence Snapshot

• 🔬✅ Well-established: Role in coagulation; prevention of vitamin K deficiency bleeding in newborns
• 🧪⚖️ Emerging/mixed: Contributions to bone markers via osteocalcin activation
• ⚠️❌ Unproven/hype: Broad cardiovascular claims from K1 alone