Vitamin K2 is found primarily in fermented foods and animal products. The richest source by far is natto, a Japanese fermented soybean dish, but you can also get meaningful amounts from certain cheeses, egg yolks, organ meats, and other fermented foods. Unlike vitamin K1, which is abundant in leafy greens, K2 appears in a narrower range of foods, making it easier to miss in a typical Western diet.
Natto: The Richest Source Available
Natto contains roughly 775 micrograms of vitamin K2 per 100 grams, which is more than any other food by a wide margin. This sticky, pungent fermented soybean product is a staple in parts of Japan and delivers the MK-7 form of K2, a subtype that stays active in your bloodstream for up to 48 hours after you eat it. Even a small serving provides far more K2 than most people get in a full day from other foods.
The catch is that natto has a strong flavor and slimy texture that many people outside Japan find difficult. If you can acquire the taste, even eating it a few times per week significantly raises circulating K2 levels. You can find natto in the frozen section of Asian grocery stores or order it online.
Cheese and Dairy
Hard and semi-hard cheeses are among the best Western dietary sources of K2. The vitamin is produced by bacteria during the aging process, so longer-aged cheeses tend to contain more. Gouda is a standout: a 26-week aged Gouda contains about 73 micrograms per 100 grams, while younger Gouda (aged 4 weeks) has closer to 47 micrograms per 100 grams. Edam delivers a similar amount, around 65 micrograms per 100 grams.
Other cheeses like cheddar, blue cheese, and Swiss also contain K2, though generally in smaller amounts than Gouda or Edam. Soft cheeses and processed cheese products tend to have less. Full-fat versions provide more than reduced-fat versions, both because K2 is fat-soluble and because the bacterial cultures in full-fat cheese produce more of it. Butter and full-fat milk contribute small amounts as well, especially when they come from grass-fed animals.
Egg Yolks and Organ Meats
Egg yolks contain about 15.5 micrograms of K2 (as MK-4) per 100 grams of yolk. Since a large egg yolk weighs roughly 17 grams, a single egg gives you about 2.6 micrograms. That’s modest, but eggs are eaten so frequently that they add up over time. Pasture-raised chickens that eat insects and greens tend to produce yolks with higher K2 content than conventionally raised birds, though exact numbers vary.
Chicken liver is another solid source, providing about 14 micrograms of MK-4 per 100 grams when raw. Cooking method matters here: pan-frying preserves more K2 (about 12.6 micrograms per 100 grams) than braising, which drops it to roughly 6.7 micrograms. Beef liver and goose liver (including pâté) also contain K2, making organ meats one of the most reliable animal-based sources.
Other Meats
Fattier cuts of meat contain more K2 than lean ones. High-fat ground beef has about 7.4 micrograms per 100 grams raw, though cooking reduces this somewhat. Dark meat poultry, pork, and processed meats like hot dogs and sausages contain smaller but measurable amounts. The K2 in meat is almost exclusively the MK-4 form, which your body clears from the bloodstream faster than the MK-7 found in fermented foods.
Fermented Vegetables
Sauerkraut provides about 2.75 micrograms of K2 per half-cup serving. That’s much less than natto or cheese, but it still counts if you eat fermented foods regularly. Kimchi contains K2 as well, though amounts vary depending on the specific bacteria involved in fermentation. These foods are best thought of as minor contributors rather than primary sources.
MK-4 vs. MK-7: Why the Form Matters
Vitamin K2 comes in several subtypes, but the two most relevant are MK-4 (found in animal products) and MK-7 (found in fermented foods, especially natto). They behave differently in your body. MK-7 is absorbed well at normal dietary doses and remains detectable in the blood for up to 48 hours. MK-4, by contrast, has such poor bioavailability at food-level doses that one study found it undetectable in subjects’ blood after eating it.
This doesn’t mean MK-4 from food is useless. Your body actually converts some vitamin K1 from leafy greens into MK-4 in specific tissues, so the picture is more complex than blood levels alone suggest. But if you’re trying to raise your overall K2 status through diet, MK-7 rich foods like natto and aged cheeses are more efficient at doing so.
What K2 Does in Your Body
Vitamin K2’s primary job is helping your body manage calcium. It activates proteins that direct calcium into your bones and teeth while keeping it out of places it doesn’t belong, like your arteries. One of these proteins binds calcium into the bone matrix, strengthening your skeleton. Another acts as an inhibitor of calcification in soft tissues, particularly blood vessels, by binding to calcium crystals and preventing them from growing.
Without enough K2, these proteins remain inactive. Calcium still circulates in your blood, but your body is less effective at putting it where it needs to go. This is why K2 is often discussed alongside calcium and vitamin D supplements: vitamin D increases calcium absorption from food, and K2 helps ensure that calcium ends up in bone rather than accumulating in arteries.
How Much You Need
There is no separate recommended daily intake for vitamin K2. Current guidelines from the National Institutes of Health set an Adequate Intake for total vitamin K (K1 and K2 combined) at 120 micrograms per day for adult men and 90 micrograms for adult women. Most people meet this through vitamin K1 from leafy greens, but that doesn’t necessarily mean their K2 intake is sufficient. The science hasn’t progressed far enough to set a firm number for K2 alone.
Many researchers studying bone and cardiovascular health have used doses in the range of 45 to 200 micrograms of MK-7 in clinical trials, which gives a rough sense of the amounts being investigated. Eating a serving of natto a few times per week or regularly including aged cheese, egg yolks, and organ meats in your diet will put you well within that range without supplements.
A Note on Blood Thinners
If you take warfarin or a similar blood thinner, be cautious with K2-rich foods. Vitamin K2 directly counteracts warfarin’s mechanism. Even moderate doses can significantly delay how quickly your blood-thinning levels return to their target range after an interruption. Clinical data show that 20 mg of K2 extended the recovery time for normal anticoagulation from about 8 hours to 100 hours. While dietary amounts are far smaller than 20 mg, sudden changes in K2 intake can still destabilize your dosing. Keep your intake consistent and let your prescriber know about any dietary shifts.