How do vegetarians get vitamin K2? A Comprehensive Guide

December 12, 2025 •

4 min read

While vitamin K1 is abundant in green leafy vegetables, vitamin K2 is less common in typical plant-based foods, posing a unique challenge for vegetarians. However, understanding the right dietary and supplemental strategies can help ensure adequate intake for essential bone and cardiovascular health.

Quick Summary

Vegetarians can obtain vital vitamin K2 by consuming specific fermented foods like natto and certain dairy products. Supplements derived from fermented sources are another reliable option for meeting nutritional needs, particularly the highly bioavailable MK-7 form.

Key Points

Rely on Fermented Foods: Natto (fermented soybeans) is the most concentrated source of vegetarian vitamin K2 (MK-7).
Consider Fermented Dairy: Lacto-vegetarians can get K2 from aged cheeses like Gouda and Brie, as well as kefir.
Enhance Absorption with Fats: Always consume vitamin K2 with a source of dietary fat, such as avocado or olive oil, as it is a fat-soluble vitamin.
Supplement for Assurance: High-quality vegetarian supplements, often derived from fermented chickpeas, are a reliable way to get an optimal dose, especially the highly bioavailable MK-7 form.
Don't Forget K1: Ensure a consistent intake of K1 from leafy greens, as gut bacteria convert some K1 to K2.
Consult a Professional: It is advisable to speak with a healthcare provider before starting supplementation, particularly if you are taking blood thinners.

The Role of Vitamin K2 in the Body

Vitamin K is a fat-soluble vitamin known for its role in blood coagulation, but the subtype known as vitamin K2 (menaquinone) is increasingly recognized for its importance in bone and cardiovascular health. Specifically, K2 helps activate proteins that direct calcium to the correct places in the body, such as bones and teeth, while preventing its accumulation in soft tissues like arteries and blood vessels. This function is crucial for maintaining bone mineral density and reducing the risk of arterial calcification.

Vitamin K1 vs. Vitamin K2: What's the Difference?

To understand how to get K2, it's helpful to distinguish it from K1. Vitamin K1 (phylloquinone) is the primary form found in green, leafy vegetables and is essential for blood clotting. Vitamin K2 (menaquinone), on the other hand, is produced by bacteria and primarily found in fermented foods and animal products. The body can convert some K1 to K2, but this conversion is not always efficient enough to meet optimal K2 needs.

Key Vegetarian Sources of K2

For those following a vegetarian diet, obtaining sufficient K2 requires focusing on a few specific food groups. Unlike animal products, where K2 is more readily available, vegetarian sources are more specialized.

Natto (Fermented Soybeans): This traditional Japanese dish is, by far, the most potent dietary source of vitamin K2, specifically the highly bioavailable MK-7 form. While its strong flavor and slimy texture can be an acquired taste, just one small serving provides a significant amount of K2.
Fermented Cheeses: Certain cheeses, particularly aged and fermented varieties like Gouda, Brie, and some blue cheeses, contain meaningful amounts of K2. This is an option for lacto-vegetarians, but it's important to choose aged versions and to remember that cheese is also high in fat and calories.
Other Fermented Foods: While their K2 content is much lower than natto, other fermented vegetables like sauerkraut and kimchi contribute to overall intake and support gut health. A healthy gut microbiome can assist in the endogenous production of K2.

Relying on Conversion and Supplements

The K1-to-K2 Conversion

Since K2 is less available in plant foods, some vegetarians rely on the body's internal process of converting vitamin K1 to K2. This conversion occurs with the help of bacteria in the large intestine. While it offers a baseline level, it may not be enough to achieve optimal levels, especially for bone and cardiovascular benefits. Therefore, consistently consuming foods rich in K1 is a good practice. These include:

Kale and other leafy greens
Spinach
Broccoli
Brussels sprouts
Soybean and canola oils

Vegetarian Vitamin K2 Supplements

Many vegetarians, especially vegans, opt for supplements to ensure adequate K2 intake. This is often the most reliable way to obtain the optimal dosage. Many high-quality, plant-based supplements are available, typically containing MK-7 derived from fermented chickpeas. MK-7 is generally preferred in supplement form due to its longer half-life compared to MK-4, meaning it remains active in the body for an extended period.

Choosing the Right Supplement

When selecting a vegetarian K2 supplement, consider these factors:

Source: Look for supplements derived from fermented chickpeas or other plant-based sources.
Form: Choose a product that specifies it contains Menaquinone-7 (MK-7), as it has superior bioavailability.
Quality: Verify the supplement is third-party tested for purity and potency. Look for certifications like 'all-trans MK-7'.
Combination: Many K2 supplements are combined with vitamin D3, as they work synergistically. Ensure the D3 is also plant-based, often sourced from lichen.

Comparison Table: Vitamin K1 vs. Vitamin K2


Feature	Vitamin K1 (Phylloquinone)	Vitamin K2 (Menaquinone)
Primary Sources	Green leafy vegetables, some oils	Fermented foods (natto, cheese), animal products
Biological Role	Primarily blood clotting	Bone health and cardiovascular health
Major Forms	K1	MK-4, MK-7, MK-8, MK-9
Location in Body	Concentrates in the liver	Found in extra-hepatic tissues (bones, arteries)
Half-Life	Short	Long (especially MK-7)

Strategies for Maximum Absorption

Because vitamin K is fat-soluble, consuming it with dietary fat significantly increases its absorption. This can be easily achieved within a vegetarian diet.

Add Healthy Fats: Pair K-rich foods like leafy green salads with a fat source such as olive oil-based dressing, avocado, nuts, or seeds.
Combine Nutrients: As mentioned, K2 works synergistically with vitamin D3. Combining a supplement or food sources can enhance the health benefits.
Mind Medications: Be aware that certain medications, particularly blood thinners like warfarin, can interfere with vitamin K metabolism. Consistent intake is crucial, and it is vital to consult a doctor before starting any supplementation. For more information, you can reference reliable sources like The Vegan Society.

Conclusion

While some animal products contain significant amounts of vitamin K2, vegetarians can effectively meet their nutritional needs through a targeted diet and supplementation. Fermented foods, particularly natto, are the most potent natural source, while fermented dairy offers a viable option for lacto-vegetarians. For guaranteed and optimal intake, especially for specific health goals like supporting bone and heart health, high-quality vegan supplements containing MK-7 are a highly effective solution. By combining these strategies with dietary fats to enhance absorption, vegetarians can ensure a robust vitamin K2 status for long-term health.

Frequently Asked Questions

Vitamin K2, or menaquinone, is a fat-soluble vitamin that activates proteins responsible for binding calcium to bones and preventing its buildup in arteries. Vegetarians need to be mindful of K2 intake to support optimal bone and cardiovascular health, as it is less common in many plant-based foods compared to K1.

The most potent vegetarian source of K2 is natto, a Japanese fermented soybean dish, which contains a high concentration of MK-7. Other sources include fermented cheeses (for lacto-vegetarians) and smaller amounts from fermented vegetables like sauerkraut.

It is challenging to obtain sufficient K2 from a standard vegetarian diet without including specific fermented foods like natto. While the gut microbiome can convert some K1 to K2, this process may not produce optimal levels, making supplements a reliable option for many.

MK-4 has a shorter half-life and is rapidly cleared from the body, whereas MK-7 has a much longer half-life, meaning it stays active in the bloodstream for a longer period. For supplementation, MK-7 is often considered more effective due to its enhanced bioavailability.

While gut bacteria do produce vitamin K2, the amount and reliability of this production are highly individual and depend on the health of your microbiome. Most experts agree that relying solely on gut bacteria for K2 is not a dependable strategy for ensuring optimal nutritional status.

Vitamin K2 is fat-soluble, so consuming it with dietary fat is key for absorption. Add healthy fats like olive oil, avocado, nuts, and seeds to meals containing fermented foods or take supplements with a meal containing fat.

For those who do not regularly consume natto or fermented dairy, a vitamin K2 supplement is a reliable way to ensure adequate intake. It is particularly recommended for those concerned about bone and cardiovascular health.

No. Many K2 supplements contain MK-4, which can be derived from animal sources. Look for supplements explicitly labeled as 'vegetarian' or 'vegan,' which often contain MK-7 sourced from fermented plant material like chickpeas.