What it does in the body
- Activation of coagulation factors (II, VII, IX, X) and anticoagulant proteins (C, S, Z)
- Osteocalcin carboxylation for bone mineralization
- Matrix GLA protein activation preventing arterial calcification
- Cell growth regulation and apoptosis
- Anti-inflammatory effects via suppression of NF-kB signaling
How much you need (Daily Value)
| Group | Recommended | Source |
|---|---|---|
| Adult male | 120 mcg | NIH/IOM |
| Adult female | 90 mcg | NIH/IOM |
| Pregnancy | 90 mcg | WHO/IOM |
| Children | 30-75 mcg (ages 1-13) | WHO |
| Older adults | 120 mcg (male), 90 mcg (female) | NIH |
Richest food sources
| Food | Amount | Where |
|---|---|---|
| Natto (fermented soybeans) | 1103 mcg MK-7 per 100g | Japan |
| Kale (raw) | 817 mcg K1 per 100g | global |
| Collard greens (cooked) | 623 mcg K1 per 100g | Americas/Africa |
| Spinach (cooked) | 493 mcg K1 per 100g | global |
| Broccoli (cooked) | 141 mcg K1 per 100g | global |
| Gouda cheese | 73 mcg MK per 100g | Europe |
| Chicken liver | 13 mcg MK-4 per 100g | global |
| Sauerkraut | 4.8 mcg K2 per 100g | Central/Eastern Europe |
In our food database, per 100 g
Highest among our free foods — open the Food Explorer to compare.
If you don't get enough
Mild: Elevated undercarboxylated osteocalcin, subtle coagulation changes (prolonged PT)
Moderate: Easy bruising, prolonged bleeding from wounds, epistaxis
Severe: Hemorrhagic disease (particularly neonates), uncontrolled bleeding, intracranial hemorrhage in infants
Time to onset: 1-2 weeks without dietary intake (body stores are limited compared to other fat-soluble vitamins)
Too much
Upper limit: No established UL for K1 or K2; considered safe even at high doses
Natural K1/K2 have no known toxicity. Synthetic menadione (K3) can cause hemolytic anemia and jaundice, especially in infants — no longer used clinically.
How well you absorb it
K1 from vegetables: 5-15%; K1 from oils/supplements: 80%; K2 (MK-7): nearly 100%
Helped by: Dietary fat, Processing/cooking of vegetables (releases K1 from chloroplast membranes), Bile salts
Hindered by: Fat malabsorption, Broad-spectrum antibiotics (kill K2-producing gut bacteria), Warfarin (antagonist), High-dose vitamin A or E
Cooking & storage
Vitamin K1 is heat-stable and not significantly destroyed by cooking. Cooking with oil actually enhances K1 absorption from leafy greens by increasing fat availability.
Nutrisize Health totals every nutrient from what you actually eat, against targets set for your age and sex, and flags what's short — across 4,995 foods, on your device.
