Where do you naturally get K2 from? A comprehensive guide to dietary sources

December 8, 2025 •

4 min read

According to the Cleveland Clinic, many of the best sources of Vitamin K2 are not traditionally part of a Western diet, which makes understanding its origins essential. If you are wondering where do you naturally get K2 from, the answer lies predominantly in fermented foods and animal products, and through synthesis by gut bacteria.

Quick Summary

Vitamin K2, or menaquinone, is a fat-soluble nutrient obtained from fermented foods like natto and from certain animal products such as liver, egg yolks, and cheese. It is also produced in small quantities by intestinal bacteria and is vital for bone and heart health by regulating calcium metabolism.

Key Points

Rich in fermented foods: The richest source of K2, especially the MK-7 type, is natto, a fermented Japanese soybean dish.
Found in animal products: Animal-based foods like grass-fed egg yolks, liver, and certain cheeses are excellent sources of the MK-4 type of K2.
Gut bacteria produce K2: A healthy gut microbiome produces small amounts of K2 (menaquinones), although this source is not reliably absorbed in sufficient quantities.
K1 to K2 conversion is limited: The body can convert K1 from leafy greens into K2, but this process is inefficient, making direct K2 intake from food important.
Eat with fat for absorption: As a fat-soluble vitamin, K2 is best absorbed when consumed alongside a dietary fat, such as with egg yolks or grass-fed butter.
K2 supports bone and heart health: Vitamin K2 is vital for directing calcium to bones and away from arteries, supporting strong bones and cardiovascular health.
MK-7 vs. MK-4: MK-7, from fermented foods, is highly bioavailable with a long half-life, while MK-4, from animal products, has a short half-life.

Understanding the Two Main Forms of Vitamin K

Vitamin K is a fat-soluble nutrient known for its role in blood coagulation. However, this is primarily the function of Vitamin K1 (phylloquinone), which is abundant in green leafy vegetables. Vitamin K2 (menaquinone) is a distinct type with different physiological roles, particularly in bone and heart health, and is found in entirely different food sources. Understanding this distinction is the first step in identifying where to naturally get K2 from.

The Importance of Vitamin K2 (Menaquinone)

While K1 is crucial for blood clotting, K2 acts as a cofactor for proteins that regulate where calcium is deposited in the body. Specifically, K2 activates osteocalcin, which helps bind calcium to the bone matrix, and Matrix Gla Protein (MGP), which prevents calcium from accumulating in soft tissues like arteries and kidneys. This mechanism explains K2's importance for both bone density and cardiovascular health.

Fermented Foods: The Top Source of MK-7

Fermentation is a powerful process that produces the highly bioavailable MK-7 form of vitamin K2. Bacteria like Bacillus subtilis are responsible for this conversion.

Natto (Fermented Soybeans): The undisputed champion of dietary K2, natto is a traditional Japanese food made from fermented soybeans. A single tablespoon can provide over 150 micrograms of vitamin K2, far exceeding the content of other foods. Its high concentration of MK-7 is a primary reason it is so effective, though its strong, pungent taste can be an acquired preference.

Sauerkraut: Made from fermented cabbage, sauerkraut contains beneficial probiotics that can boost gut health, and it provides a small but notable amount of K2.

Fermented Dairy Products: Cheeses, particularly hard varieties like Gouda and soft, aged cheeses such as Brie, contain significant amounts of K2. The bacterial cultures involved in the aging process synthesize menaquinones, including MK-7, MK-8, and MK-9. Kefir, a fermented milk drink, also provides a probiotic source of K2.

Animal Products: A Primary Source of MK-4

Animal products contain a different form of vitamin K2 known as MK-4, which is converted from vitamin K1 by the animal’s body and concentrated in certain tissues. The quality of these products, specifically whether they come from grass-fed or grain-fed animals, can influence their K2 content.

Organ Meats: Liver, especially from beef or chicken, is one of the richest animal-based sources of K2. Goose liver pâté is particularly potent.

Egg Yolks: Pasture-raised eggs contain significantly higher levels of K2 (MK-4) than those from conventionally raised chickens. The fat-soluble nature of K2 means it is stored in the yolk, not the white.

Grass-Fed Dairy and Butter: Dairy products from grass-fed cows, including butter and hard cheeses, are superior sources of K2. The cows consume K1 from the grass and convert it into K2, which is then passed into their milk.

Meat: Dark chicken meat is a decent source of K2, containing more than beef or pork. Cured and processed meats like salami also contain K2, but should be consumed in moderation due to other health considerations.

Beyond Diet: The Role of Gut Bacteria

While diet is the main source of functionally available K2, the bacteria in your gut can also produce some menaquinones, especially in the large intestine. However, the extent to which this homegrown K2 is absorbed is debated, and it is likely insufficient to meet optimal requirements. A healthy, diverse gut microbiome is beneficial for overall health, but relying on it for K2 is unreliable.

Comparing Key Natural K2 Sources


Source Category	Specific Food	K2 Form	Notes
Fermented Food	Natto	MK-7	Richest source, but often unpalatable; great for gut health.
Fermented Food	Hard Cheeses (e.g., Gouda)	MK-7, MK-8, MK-9	Widely available, decent source of multiple menaquinones.
Animal Product	Egg Yolk (pasture-raised)	MK-4	Excellent, readily available source; high in other nutrients.
Animal Product	Liver (beef/chicken)	MK-4	Very high concentration, but less commonly consumed.
Animal Product	Grass-Fed Butter	MK-4	Good source, best from pasture-raised animals.
Fermented Food	Sauerkraut	MK-7	Moderate source, supports gut health.

Maximizing Your Natural K2 Intake

To ensure you get enough K2 from natural sources, consider incorporating a mix of both fermented foods and animal products into your diet. Since K2 is fat-soluble, consuming it with dietary fats can enhance absorption. A balanced approach that doesn't rely on a single food item is ideal, as the concentration of K2 can vary widely. For example, pairing leafy greens (high in K1) with a healthy fat like olive oil may also help facilitate the body's limited conversion to K2.

Conclusion

For those seeking where do you naturally get K2 from, the answer is a combination of select animal and fermented products. Natto stands out as the most potent source of MK-7, while grass-fed dairy, egg yolks, and organ meats provide substantial MK-4. A healthy gut microbiome also contributes, but its production is not as reliable as dietary intake. By deliberately including these diverse foods in your diet, you can support robust bone and heart health, unlocking the benefits of this often-overlooked nutrient.

To learn more about the specific health benefits of vitamin K2, you can visit the Kerry Health and Nutrition Institute website.

Frequently Asked Questions

The single best natural source of vitamin K2 is natto, a traditional Japanese food made from fermented soybeans, which contains exceptionally high levels of the MK-7 form.

No, leafy greens are a primary source of Vitamin K1. While your body can convert some K1 to K2, the process is inefficient. To get sufficient K2, you need to consume fermented or animal-based products.

Intestinal bacteria do produce small amounts of K2, but the bioavailability is considered poor, and relying on this source alone is insufficient for optimal health. Dietary intake is the most reliable way to get K2.

Hard and soft aged cheeses, such as Gouda, Brie, and Edam, contain good levels of vitamin K2. The fermentation process used to make these cheeses is what produces the menaquinones.

Yes, products from grass-fed animals typically have significantly higher vitamin K2 content because the animals convert the K1 from their diet of grass more efficiently than grain-fed animals.

Vitamin K2 helps prevent cardiovascular issues by activating a protein called MGP (Matrix Gla-Protein), which helps remove calcium deposits from your arteries and other soft tissues.

Supplements can be a reliable option, especially if you dislike the taste of natto or don't consume many other K2-rich foods. However, many experts still recommend obtaining nutrients from whole foods where possible, and a healthcare provider should be consulted before starting supplementation.