Vitamin K is a fat-soluble vitamin that plays a crucial role in blood clotting, bone metabolism, and cardiovascular health. It exists in two main forms:
Vitamin K1 (Phylloquinone) – Found primarily in leafy green vegetables, it is essential for proper blood coagulation.
Vitamin K2 (Menaquinone) – It supports bone health and prevents arterial calcification in animal-based and fermented foods.
While both forms of Vitamin K contribute to overall health, they have distinct roles in the body, making it essential to ensure adequate intake of both forms. Vitamin K2 is, indeed, one of the most overlooked nutrients for heart health.
How Vitamin K1 & K2 Work in the Body
Vitamin K1 (Phylloquinone):
- Primarily used by the liver to activate clotting factors, preventing excessive bleeding.
- Helps maintain proper blood viscosity and prevents hemorrhaging.
- Just like Vitamin D, K1 plays a minor role in bone health but is less effective than K2 in this function.
Vitamin K2 (Menaquinone):
- Activates osteocalcin, a protein that binds calcium to bones, improving bone density. Deficiency leads to free calcium in blood, causing calcification of arteries.
- Works with matrix Gla protein (MGP) to prevent calcium buildup in arteries, reducing the risk of heart disease.
- Supports dental health by assisting in remineralization.
Signs of Vitamin K1 & K2 Deficiency
Vitamin K1 Deficiency:
- Easy bruising and excessive bleeding.
- Slow wound healing.
- Blood in stool or urine (in severe cases).
Vitamin K2 Deficiency:
- Osteoporosis or weak bones.
- Increased risk of fractures.
- Arterial stiffness and cardiovascular issues due to calcium deposits.
- Dental cavities and poor oral health.
Recommended Dietary Allowance (RDA) and Optimal Allowance of K1 & K2
The RDA for Vitamin K (based on general recommendations):
- Men: 120 mcg/day
- Women: 90 mcg/day
- However, optimal health benefits may require higher doses, especially for Vitamin K2. Studies suggest that K2 (MK-7 form) in doses of 100–200 mcg/day provides better cardiovascular and bone health support.
Plant & Meat Sources of Vitamin K
Best Sources of Vitamin K1:
- Leafy greens (Kale, Spinach, Collard Greens, Swiss Chard)
- Broccoli
- Brussels Sprouts
- Parsley
Best Sources of Vitamin K2:
- Animal-based sources: Liver, egg yolks, butter, cheese, natto (fermented soybeans), and fatty meats.
- Fermented foods: Sauerkraut, kimchi, miso.
Types of Supplements
Supplements come in various forms, each with unique benefits:
- Vitamin K1 Supplements: Usually available as phylloquinone in tablet or softgel form.
- Vitamin K2 Supplements: Available in different menaquinone forms:
- MK-4: Found in animal products, has a shorter half-life, requires multiple daily doses.
- MK-7: Found in natto, has a longer half-life and requires only one daily dose.
Delivery Methods:
- Oral Tablets/Capsules – The most common form, best taken with meals for better absorption.
- Softgels or Liquid Drops – These have Faster absorption and are ideal for individuals with digestive issues.
- Liposomal K2 – Encapsulated in fat-based particles for superior bioavailability.
- Intramuscular Injection – Used in hospitals to treat severe deficiencies or for newborns.
Cautions
- Blood Thinners (Warfarin): Vitamin K can interfere with anticoagulant medications, requiring dosage adjustments.
- Excessive Intake: Though rare, excessive K1 intake can impair anticoagulant medication effects, however, very high doses of K2 might contribute to hypercalcemia if taken with high-dose Vitamin D.
- Fat Absorption Issues: Conditions like celiac disease, Crohn’s disease, or gallbladder issues may impair Vitamin K absorption.
Conclusion
Vitamin K1 and K2 are essential for maintaining proper blood clotting, bone strength, and cardiovascular health. While K1 is crucial for clotting, K2 plays a significant role in calcium metabolism and heart health. Ensuring an adequate intake through diet and supplementation (when necessary) can prevent deficiencies and improve overall well-being. needed, and appropriate supplements, you can support optimal health and well-being.
