Does Everyone Need Vitamin K2? Unpacking the Science of This Essential Nutrient

December 31, 2025 •

4 min read

Despite being discovered nearly a century ago, the distinct functions of vitamin K2 in promoting bone density and cardiovascular health are often overlooked. This raises the critical question: does everyone need vitamin K2 for optimal health, or are some at higher risk of deficiency?

Quick Summary

Vitamin K2 directs calcium to bones and prevents arterial buildup, playing a key role in heart and bone health. Deficiency is more common in Western diets, affecting those with poor intake or specific health issues, suggesting a need for increased attention.

Key Points

Not all vitamin K is the same: Vitamin K1 is vital for blood clotting and is found in greens, while Vitamin K2 is crucial for bone and heart health and is found in fermented foods and animal products.
K2 prevents arterial calcification: It activates a protein that moves calcium out of arteries and into bones, significantly reducing a major risk factor for heart disease.
Bone density relies on K2: K2 activates osteocalcin, a protein that directs calcium to the skeleton, helping to strengthen bones and combat osteoporosis.
Western diets are often low in K2: Many common foods lack sufficient K2, making deficiency more likely in modern populations compared to traditional diets featuring fermented foods.
High-risk groups should be vigilant: Individuals with gut issues, on certain medications like warfarin, or following specific diets (vegan/vegetarian) are at higher risk for low K2 levels.
Consult a doctor before supplementing: K2 can interfere with blood-thinning medication, making it essential to speak with a healthcare provider before adding a supplement.

The Difference Between Vitamin K1 and Vitamin K2

Vitamin K is not a single entity but a family of fat-soluble vitamins with two main forms: K1 (phylloquinone) and K2 (menaquinones). While both are essential, they have distinct functions and sources. Vitamin K1 is primarily involved in blood clotting and is abundantly found in leafy green vegetables. In contrast, vitamin K2's main role is to regulate calcium, ensuring it is deposited in the bones and teeth rather than the arteries and soft tissues. The body can convert some K1 into K2, but this process is highly inefficient, meaning direct dietary intake of K2 is more effective for accessing its unique health benefits.

The Crucial Role of Vitamin K2 in Your Body

Vitamin K2 activates specific proteins that are essential for regulating calcium metabolism, a function that vitamin K1 does not perform as effectively. This mechanism explains K2's profound impact on cardiovascular and skeletal health.

Bone and Cardiovascular Health

Bone Mineralization: Vitamin K2 activates osteocalcin, a protein that binds calcium to the bone matrix. Adequate K2 levels ensure calcium is efficiently used to build and strengthen bones, helping to prevent and manage conditions like osteoporosis. Studies in postmenopausal women have shown that K2 supplementation can reduce the risk of fractures and maintain bone mineral density.
Arterial Decalcification: K2 activates another protein, Matrix Gla Protein (MGP), which prevents calcium from being deposited in soft tissues, especially the arteries. This protective function is crucial for preventing arterial calcification, a major risk factor for heart disease. Population-based studies have linked higher K2 intake with a significantly reduced risk of coronary heart disease.

Other Potential Benefits

Beyond its established roles, research is exploring other health areas where K2 may play a role:

Dental Health: By activating osteocalcin, K2 also helps stimulate the growth of new dentin, the calcified tissue beneath tooth enamel, supporting strong teeth.
Cognitive Function: Some studies suggest a link between vitamin K levels and cognitive function, with potential implications for preventing age-related decline and neurodegenerative diseases.
Diabetes: Emerging research indicates that K2 may improve insulin sensitivity, contributing to better glycemic control.

Who Is at Risk for Vitamin K2 Deficiency?

While overall vitamin K deficiency is rare, suboptimal levels of K2 are common, especially with modern Western diets. Certain populations are at a higher risk of deficiency and may particularly benefit from increased intake:

Postmenopausal Women and Older Adults: This group is at a higher risk for osteoporosis and cardiovascular issues, making K2 intake especially important.
Individuals with Gastrointestinal Conditions: Conditions like celiac disease or cystic fibrosis can impair fat absorption, affecting the body's ability to absorb fat-soluble vitamins, including K2.
People on Long-Term Antibiotics: Antibiotics can disrupt the gut bacteria responsible for producing some K2.
Vegetarians and Vegans: Since K2 is predominantly found in animal products and fermented foods, those following a plant-based diet without including fermented items are likely to have lower intake.

How to Get Enough Vitamin K2: Diet vs. Supplements

Since K2 is less prevalent in the average diet than K1, a targeted approach may be necessary. For most people, focusing on dietary sources is the best first step. However, supplementation can be a viable option, especially for high-risk individuals.

Food Sources of Vitamin K2

Vitamin K2 exists in various forms, known as menaquinones (MKs). MK-4 is found in animal products, while longer-chain menaquinones like MK-7 are common in fermented foods. Incorporating these foods can help boost your K2 levels.

Natto: This traditional Japanese fermented soybean dish is the richest known food source of K2 (MK-7).
Cheeses: Hard and soft cheeses, such as Gouda, Brie, and Cheddar, contain moderate to high levels of K2.
Grass-Fed Dairy: Full-fat milk, butter, and yogurt from grass-fed cows are better sources of MK-4 than conventional dairy.
Organ Meats: Beef liver and goose liver contain significant amounts of MK-4.
Egg Yolks: High-quality egg yolks, particularly from pasture-raised chickens, are a good source of K2.
Cured and Fermented Meats: Some processed meats like salami and prosciutto contain menaquinones.

Comparison Table: Vitamin K1 vs. Vitamin K2


Feature	Vitamin K1 (Phylloquinone)	Vitamin K2 (Menaquinones)
Primary Sources	Leafy greens (spinach, kale), broccoli, vegetable oils	Fermented foods (natto), hard/soft cheeses, organ meats, grass-fed dairy, egg yolks
Main Function	Blood clotting	Calcium regulation (directing it to bones) and preventing soft tissue calcification
Absorption Rate	Absorbed less efficiently than K2	Absorbed more efficiently, especially the MK-7 subtype
Half-Life	Short half-life, cleared quickly from the blood	Long half-life, remains in the body for several days
Systemic Impact	Primarily liver-focused	Works on bones and blood vessels throughout the body

The Vitamin D3 and K2 Connection

Vitamin K2 and Vitamin D3 work synergistically, playing critical and complementary roles in calcium metabolism. Vitamin D3 increases calcium absorption from food, while vitamin K2 ensures that this absorbed calcium is properly utilized. Combining these two nutrients is often recommended to maximize their benefits for bone and heart health.

Supplementation Considerations

For those who do not consume enough K2-rich foods, supplementation can be effective. However, it is essential to consult a healthcare provider before starting, especially due to potential interactions. Most notably, vitamin K2 can interfere with blood-thinning medications like warfarin, requiring careful monitoring.

Conclusion

While not everyone needs a vitamin K2 supplement, nearly everyone needs adequate levels of this nutrient for optimal long-term bone and cardiovascular health. Deficiency is far more common than many realize, especially given the low K2 content in typical Western diets. By understanding the distinct roles of K1 and K2 and incorporating more K2-rich foods, or considering supplementation under medical guidance, individuals can proactively support their skeletal integrity and protect against arterial calcification. For those in high-risk categories, such as older adults or people with gastrointestinal issues, paying special attention to K2 intake is particularly important for mitigating potential health risks. A balanced diet rich in both K1 and K2 sources provides the most comprehensive nutritional support.

Frequently Asked Questions

The primary difference lies in their function and source. Vitamin K1, found in leafy greens, is mainly involved in blood clotting. Vitamin K2, found in fermented and animal products, regulates calcium metabolism, promoting bone mineralization and preventing arterial calcification.

While most people can get enough K2 from a diverse diet, supplementation may be beneficial for older adults, postmenopausal women, people with gastrointestinal conditions affecting absorption, or those with very limited dietary K2 intake.

For most healthy individuals, vitamin K2 is considered safe and has low potential for toxicity. However, it can have dangerous interactions with blood-thinning medications like warfarin. Anyone on anticoagulants must consult a doctor before supplementing.

The richest food source is natto (fermented soybeans). Other good sources include hard and soft cheeses (Gouda, Brie), goose liver pate, egg yolks, and organ meats, particularly from grass-fed animals.

Vitamin D3 enhances the absorption of calcium, while vitamin K2 directs that calcium to where it is needed, primarily the bones and teeth. This synergistic relationship is crucial for both bone and cardiovascular health.

There is no official Recommended Dietary Allowance (RDA) specifically for vitamin K2. While no specific dosage is universally recommended, ensuring adequate intake through diet or supplementation under professional guidance is important for bone and cardiovascular health.

It can be challenging, as most dietary K2 comes from animal products. However, natto is a rich vegan source, and some fermented foods like sauerkraut also contain K2, though in lower amounts. Vegetarians and vegans may benefit from supplementation.