Vitamin K
Also known as: Phylloquinone, Menaquinone, Vitamin K2, Vitamin K1
Vitamin K is a fat-soluble vitamin essential for blood clotting and bone metabolism. It exists in two main forms: K1 (phylloquinone) found primarily in plants, and K2 (menaquinone) produced by gut bacteria and found in fermented foods. Vitamin K activates proteins necessary for calcium binding in bones and teeth.
Benefits
Essential for proper blood clotting and wound healing. Critical for bone mineralization and may reduce risk of osteoporosis. Supports cardiovascular health by regulating calcium in blood vessels. May reduce risk of arterial calcification. Supports proper calcium distribution to bones rather than soft tissues. May improve bone density in postmenopausal women.
Recommended Dosage
AI: 90 mcg/day for women, 120 mcg/day for men. Supplement doses vary: K1 typically 45–180 mcg daily, K2 (MK-7) typically 90–200 mcg daily. No established upper limit from dietary or supplemental sources. Take with meals containing fat for absorption. Different forms have different absorption rates and bioavailability.
Food Sources
Leafy greens (kale, spinach, collard greens, broccoli, cabbage), Brussels sprouts, asparagus, green beans, cauliflower, fermented foods (natto, sauerkraut, kimchi), cheese, egg yolks, beef liver, chicken.
Side Effects
Generally very safe with minimal side effects. High supplemental doses rarely cause: mild rash, skin reactions, or gastrointestinal upset. Excess vitamin K does not cause toxicity like fat-soluble vitamins A, D, and E. Some people may experience headache or muscle soreness.
Interactions
Anticoagulants (warfarin, acenocoumarol) are antagonized by vitamin K — consistent intake is important. Antibiotics can reduce K2 production in the gut. May reduce effectiveness of some anticonvulsants. Mineral oil laxatives reduce absorption.
Warnings
People taking warfarin should maintain consistent vitamin K intake and consult their doctor before supplementing. Do not suddenly increase vitamin K intake if on anticoagulants. Those with liver disease should use caution. Not recommended for people with clotting disorders.
Deficiency Symptoms
Easy bruising and prolonged bleeding from minor cuts. Excessive nosebleeds and bleeding gums. Blood in urine or stool. Heavy menstrual bleeding. Reduced bone density and increased fracture risk (long-term deficiency).
Frequently Asked Questions
What are the benefits of Vitamin K?▼
Essential for proper blood clotting and wound healing. Critical for bone mineralization and may reduce risk of osteoporosis. Supports cardiovascular health by regulating calcium in blood vessels. May reduce risk of arterial calcification. Supports proper calcium distribution to bones rather than soft tissues. May improve bone density in postmenopausal women.
What is the recommended dosage for Vitamin K?▼
AI: 90 mcg/day for women, 120 mcg/day for men. Supplement doses vary: K1 typically 45–180 mcg daily, K2 (MK-7) typically 90–200 mcg daily. No established upper limit from dietary or supplemental sources. Take with meals containing fat for absorption. Different forms have different absorption rates and bioavailability.
What foods contain Vitamin K?▼
Leafy greens (kale, spinach, collard greens, broccoli, cabbage), Brussels sprouts, asparagus, green beans, cauliflower, fermented foods (natto, sauerkraut, kimchi), cheese, egg yolks, beef liver, chicken.
What are the side effects of Vitamin K?▼
Generally very safe with minimal side effects. High supplemental doses rarely cause: mild rash, skin reactions, or gastrointestinal upset. Excess vitamin K does not cause toxicity like fat-soluble vitamins A, D, and E. Some people may experience headache or muscle soreness.
What are the symptoms of Vitamin K deficiency?▼
Easy bruising and prolonged bleeding from minor cuts. Excessive nosebleeds and bleeding gums. Blood in urine or stool. Heavy menstrual bleeding. Reduced bone density and increased fracture risk (long-term deficiency).
Related Supplements
Vitamin D
Vitamins
Vitamin D is a fat-soluble vitamin that plays a crucial role in calcium absorption, bone health, immune function, and mood regulation. Unlike most vitamins, your body can produce vitamin D when your skin is exposed to sunlight, earning it the nickname 'the sunshine vitamin.'
Vitamin C
Vitamins
Vitamin C is a water-soluble vitamin and powerful antioxidant that the human body cannot produce on its own. It is essential for the growth, development, and repair of all body tissues and plays a role in many body functions including immune defense, collagen formation, and iron absorption.
Omega-3 Fish Oil
Fatty Acids
Omega-3 fatty acids are essential polyunsaturated fats that your body cannot make on its own. The two most important omega-3s found in fish oil are EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). They play critical roles in brain function, heart health, and reducing inflammation throughout the body.
Supplement Disclaimer
This supplement information is for educational purposes only and should not replace professional medical advice. Dietary supplements are not intended to diagnose, treat, cure, or prevent any disease. Always consult with a healthcare provider before starting any supplement, especially if you are pregnant, nursing, taking medications, or have a medical condition.