Vitamin K is a fat soluble vitamin. The fitoquinona, natural form of vitamin K found in alfalfa and other foods, was discovered in Denmark and designated as vitamin K for the Danish word koagulation.
Phylloquinone providing food is designated as K1, while menaquinone produced by our intestinal bacteria called vitamin K2. A synthetic compound with the basic structure of the quinones is menadione or vitamin K3.
Vitamin K is important for proper blood clotting in humans. It is essential for synthesis in the liver of four coagulation proteins.
Without vitamin K, the level of blood clotting proteins is reduced and clotting time is prolonged. A K protein is also recognized a role in the maintenance and bone health.
Since natural vitamin K is fat soluble, requires bile and pancreatic juice into the intestine for maximum absorption. By contrast, some synthetic vitamin K compounds (K3) are water soluble and are absorbed more easily, so they are used by people who do not tolerate natural vitamin K, such as those with an impaired secretion of bile acids.
The absorption of vitamin K takes place primarily in the upper small intestine with the help of bile or bile salts and pancreatic juices, and transported to the liver for synthesis of prothrombin, a key factor in blood clotting.
Vitamin K is found in nature in both animal and vegetable sources. Buenos supplements found in leafy pasture, in most green plants, the alfalfa and kelp. Black molasses sugar and polyunsaturated oils such as safflower, also contain some vitamin K.
In animal foods, vitamin K is found in liver, milk, yogurt, egg Yeme and fish liver oils. The best source for humans is that provided by intestinal bacteria and that is why vitamin K supplementation is particularly important for those whose normal balance in the intestinal flora has been altered.