Answer :Vitamin K comes in two main forms. K1, found in leafy green and cruciferous vegetables, makes up about 90% of our dietary vitamin K. The second, less-familiar type is broadly known as vitamin K2. Sarah L. Booth, PhD, director of Tufts HNRCA Vitamin K Research Laboratory, explains: Vitamin K2 covers many forms, all of which have different sources. One form, menaquinone-4, is found in most dairy products and poultry. However, it is primarily formed in our body from the dietary form, vitamin K1. Some minor forms are found in fermented soybean products and fermented cheese, but not in processed cheese. We also make K2 in our intestines.
Much of what is known about the content of vitamin K in the US food supply comes from research conducted in the HNRCAs Vitamin K laboratory. Extensive databases now exist for the vitamin K1 content of various foods. Similar databases for vitamin K2 are in development .