Where can I find information about the content of vitamin K in food?

Facts about vitamin K

  • Vitamin K is a fat-soluble vitamin occurring in two forms in foods. Mostly as vitamin K1 (phylloquinone), and as vitamin K2 (sum of menaquinones) in a smaller amount in some foods.
  • The K1-form occurs in plants and is made by photosynthesis
  • K2 is produced by bacteria in the intestine in animals.
  • Both forms of vitamin K also occur in animal products, but in small amounts.
  • In animal products, liver and some cheeses contain the largest amount of K2
  • Vitamin K2 is also produced by fermentation of vegetables. A fermented soybean preparation (natto) is particularly rich in vitamin K.

The absorption of vitamin K increases when fat is digested (in moderate amounts), because vitamin K is fat-soluble. Naturally deficiency of vitamin K rarely occurs, because some vitamin K2 may be produced by intestinal bacteria in humans. Reduced digesting or other problems in the intestine, such as reduced fat absorption, may cause deficiency.

Vitamin K is necessary in coagulation of blood in the body. In addition, the vitamin is an important part of the calcium-binding proteins, and it is important in the production of bone mass, working closely with vitamin D. People treated with anticoagulants should have a stable intake of vitamin K.

Main reference: Nordic Nutrition Recommendations, (Nordic Council of Ministers 2004)

Vitamin K in foods

  • Good sources of vitamin K include leafy green vegetables, such as broccoli and spinach, products of vegetable oil (particularly rapeseed-, soya- and olive oil). Some algae have a high content of vitamin K.
  • Vitamin K is quite stable during heat treatment, but it is sensitive to light. Thus, oils should be kept in a dark and preferably cold place (to prevent rancidity of the fat). Dried food has a larger concentration of vitamin K, but the concentration will change during dilution in water.

The information is gathered from the Swedish report “K-vitamin i livsmedel 4/98”.

Sources of information

  • Vitamin K is for the present not included in the Food Composition table, because the vitamin is quite new and the methods are still developing. Plans for preparing a special table with analytical values for vitamin K exist, but the time of completion is yet to be decided.
  • Vitamin K (K1 and/or K2) is listed in some foreign food composition tables. In order to evaluate the quality of the sources of data, it is recommended to read the background texts to receive information about what type of the nutrient the tables have included, and where the values come from (reference/source), for instance from analyses, calculated values, or borrowed from another food composition table. It is important to consider whether a food item is comparable with foreign products.
  • The Swedish food composition table is based on the report “K-vitamin i livsmedel 4/98” from The National Food Agency. The report is until further notice recommended as the main source when comparing with Norwegian foods. In the report, Swedish analytical data for vitamin K1 (1996-97) is compared with foreign data until 1998 (p. 35-49). On page 18 in the report, there is a limited table with values for vitamin K2.
  • The Danish food composition table does not have it’s own analytical values, but values for vitamin K1 are borrowed from the Swedish report and possibly the American table. The values are presented as vitamin K, but the table only contains values for vitamin K1.
  • The Finnish food composition table contains values for total amount of vitamin K (K1 and K2), with specification of source for every value.
  • The American table, from United States Department of Agriculture, has a separate table for vitamin K1 (Nutrient Lists), where the content is listed from the size of portions. If you want to look at the content of nutrients in a food item, you can search after foods individually in the search area (Search) or download the last updated file in the database to your computer (Download software) from the USDA National Nutrient Database for Standard Reference`s website.