Biologically, the most active is vitamin K1. The biochemical function of vitamin K is reflected in the mechanism of blood coagulation. It is well know that vitamin K is essential for normal blood plasma protein building - prothrombin, which is as inactive precursor of thrombin. Thrombin converts fibrinogen into fibrin producing clot. In this process are necessary calcium ions. Vitamin K is needed to maintain normal concentrations of blood coagulation factors II, VII, IX, and X, all of which are synthesized in the liver. All of these factors are synthesized in the liver in an inactive form, and their conversion into the active form is vitamin K dependent.
For the absorption of vitamin K in the intestines it is needed a normal fat absorption.
Since vitamin K is produced by many microorganisms, most of the plants and was discovered in the tissues of all organisms, there is the question, whether there is some other effect other than blood clotting. Some data show that it could function as a coenzyme in a specialized way of electron transfer in animal tissue.
An important role of vitamin K has in bone mineralization. Therefore, it is especially important to consume it for better healing of injured bones and to prevent and treat osteoporosis. In people with osteoporosis, calcium get out from the bones, it is also noted that the level of vitamin K is reduced. However, if vitamin K enters the body in enough quantities, this loss is reduced and consequently slows down osteoporosis. Vitamin K plays a role in bone calcification.
The experimental conditions showed that vitamin K3 can inhibit a variety of cancers (especially breast, ovarian, colon, stomach, kidney and lung cancer). The effect of this vitamin can be compared to some chemotherapeutic agents.
Vitamin K is partially accumulates in peripheral tissues, and it is not always necessary to be in the food.