Vitamin K2 foods

Which foods do K1 and K2 come from?

Phylloquinone (K1) is found in green leafy vegetables, vegetable oils and some fruits. Menaquinones (K2) are largely of bacterial origin: they are found in fermented foods such as natto and cheese and in animal products. Meat, dairy products and eggs contain low amounts of phylloquinone and, in contrast, modest amounts of menaquinone. ^[1] In the food database of Schurgers and Vermeer, K1 was found mainly in green vegetables and plant margarines; K2 in meat, liver, butter, egg yolk, natto, cheese and curd cheese types. ^[3]

NIH states that the values in the table, apart from those specified separately, are phylloquinone content, because food composition data for menaquinones are limited. ^[1] For this reason, the table below is not a complete list of K2 content.

Foods high in vitamin K and serving values

The values are taken from Table 2 in NIH’s vitamin K fact sheet; NIH uses the Daily Value (DV) of 120 µg as a comparison benchmark. Servings are US measures (1 oz is about 28 g; “cup” is the US cup measure, about 240 mL); the K content of products sold in Türkiye may differ. ^[1]

Natto and MK-7: why does it have a separate place?

Natto is soybeans fermented with Bacillus subtilis “natto”; it is widely eaten in some regions of Japan and not widely elsewhere. The review by Walther and colleagues reports studies finding about 939–998 µg of MK-7 per 100 g of natto (and also MK-8 at 84 µg/100 g and K1 at 35 µg/100 g). ^[2] The 850 µg NIH gives for 3 oz of natto is consistent with this range. ^[1]

The food matrix affects absorption. In a small study by Schurgers and Vermeer with 6 healthy men, circulating K2 levels after eating 200 g of natto (3.1 µmol K2) were about 10 times the K1 levels after eating 400 g of spinach (3.5 µmol K1); pure K1 was absorbed faster than the food-bound vitamin Ks (serum peak at 4 hours and 6 hours). The authors state that the contribution of menaquinones to vitamin K status is underestimated and that their interactions with anticoagulant therapy need to be investigated. ^[3] A study of six people does not give a definitive bioavailability ratio.

How important are cheese, dairy products and meat for K2?

Walther and colleagues report that dairy products may be the main source of dietary menaquinone in many regions, but that food composition data are limited. The long-chain forms most often found in cheeses are MK-8 and MK-9, and the amount varies greatly with the bacterial species used and fermentation conditions. The ranges reported in Table 2 of the review (µg/100 g):

ND: not detected. The ranges show the lowest and highest means in studies from the US, Europe and Japan. The same review reports that in 62 fermented dairy products examined in Europe, total long-chain menaquinone levels varied from not detectable to 118 µg/100 g, with a median of 15 µg/100 g. ^[2] For this reason, the sentence “cheese is a K2 source” is correct, but the content of a specific cheese type or brand cannot be predicted; measurements for products sold in Türkiye, such as white cheese and kaşar, are not included in this table.

The amount of MK-4 in animal foods depends on production conditions. NIH reports that in chicken and pork, MK-4 is found when menadione (a synthetic form of vitamin K) is used in feed. ^[1] Walther and colleagues report that menadione feed supplementation is common in the US and that MK-4 corresponded to about 3% of total vitamin K intake in the Netherlands. ^[2] MK-4 content is therefore expected to differ between countries.

Do gut bacteria meet K2 needs?

NIH states that bacteria in the human gut produce long-chain menaquinones and that significant amounts are found in the large intestine; how much vitamin K the body obtains this way is uncertain, but experts believe that these menaquinones meet at least part of the K requirement. ^[1] EFSA, finding the evidence on the formation, absorption and body content of menaquinones insufficient, set the reference intake value only for phylloquinone. ^[4] That is, uncertainty remains about the size of the gut contribution and about the fact that K2 foods have no separate reference value.

Comparison with reference intakes

The Daily Value (DV) used by NIH is 120 µg for adults; for a food to count as a “high source,” a serving must provide at least 20% of the DV (24 µg). According to the table, ½ cup of boiled broccoli provides 110 µg (92% of the DV), 1 cup of raw spinach 145 µg (121%), and 1 tablespoon of soybean oil 25 µg (21%); 1½ oz of cheddar gives low values such as 4 µg, and 1 cup of milk 1 µg. ^[1] The AI values reported by NIH are 120 µg for men and 90 µg for women; the AI set by EFSA for phylloquinone is 70 µg for adults. ^{[1] [4]} The contribution of K2 sources such as cheese and meat to total vitamin K intake is therefore generally small compared with green vegetables; however, this comparison applies only to the MK-4 and phylloquinone values in the table, and the effect of long-chain menaquinones is a separate and uncertain question.

From food or from supplements?

The amounts in foods are at the microgram level. NIH reports that the content of vitamin K supplements varies over a wide range, and that very high amounts such as 4,050 µg can be found in some products. ^[1] The difference between a food source and a supplement is not only amount but also form (the long half-life of MK-7) and the risk of drug interaction; these topics are covered in the main guide and the benefits page.

Vitamin K from food and warfarin

The high K1 values in the table matter for people using warfarin and similar vitamin K antagonists: NIH reports that people using these drugs should keep vitamin K intake consistent from food and supplements, and that sudden changes can increase or decrease the anticoagulant effect. ^[1] This does not mean green vegetables are forbidden; the point emphasized is that intake be regular. The nutrition plan is made together with the physician prescribing the drug and a dietitian. This page does not recommend a personal dose or diet program.