Vitamin K
History of discovery
Among the many useful and necessary for our body substances, there is a vitamin that is often overlooked. This is vitamin K. This defender of our skin, blood, bones and kidneys was discovered at the beginning of the XIX century. Danish scientist Henrik Dam was researching the effects of a lack of cholesterol among chickens. After a few weeks of feeding the chickens with the food which lacked cholesterol the hemorrhage developed - a bleeding in the muscles, subcutaneous tissue and other tissues. During the study a substance that had the ability to stop the bleeding was found. This substance was named vitamin K (from Koagulationsvitamin – coagulation vitamin). By the way, Henrik Dame in 1943 won the Nobel Prize for this discovery.
What does vitamin K do?
Vitamin K is a group of fat-soluble compounds produced in two main forms: phylloquinone (plant origin, or vitamin K1) and menaquinone (animal origin, or vitamin K2). Vitamin K is synthesized in the small section of intestine by certain microorganisms the saprophytic bacteria. The basic function of vitamin K in the body is providing the normal blood clotting; it takes part in the catalytic processes, which allow prothrombin and other coagulation proteins to bind the calcium, which in turn, is essential for the "gluing" of platelets and the formation of a blood clot. Also, vitamin K plays an important role in bone formation and repair - it provides bone protein synthesis, which crystallize calcium. It is very important for children, as well as for the unwary adults who receive themselves a fracture. Vitamin K is vital for women during menopause - at this time they often suffer from osteoporosis (bone tissue loss, which is dangerous with the long non-healing fractures).
Vitamin K increases the strength of the vessel walls. This is especially important for those who are actively engaged in physical exercise and sports - vitamin K reduces the risk of blood loss after traumas, and it also enhances the muscle contraction.
As part of the cell membranes, vitamin K is involved in the formation of the main sources of energy in the body, it normalizes the motility of the gastrointestinal tract and muscle functioning, helps to avoid the formation of kidney stones. Vitamin K is often prescribed to pregnant women in order to prevent fetal death from bleeding.
Where can vitamin K be found?
Vitamin K is found in all green plants, and its content is more or less in proportion to their content of chlorophyll. The leaves of goutweed, nettle, linden, birch, raspberries and rose hips have a lot of vitamin K. Green leafy vegetables, green tomatoes, rose hips, spinach, oats, soybeans, wheat, rye, are very rich with it. Vitamin K can be found in soybean oil, liver (especially pork), eggs, walnuts, all kinds of cabbage (white cabbage, cauliflowers, kohlrabi, broccoli). There is a lot of vitamin K in herbs: in alfalfa or, for instance, shepherd's purse. Kelp and green tea are rich with it as well. In the roots and fruits the amount of vitamin K is much smaller.
How much K do you need?
Vitamin K is synthesized mainly by the saprophytic bacteria in human small intestine and in sufficient quantity comes with food.
Lack and excess of vitamin K
Vitamin K is not toxic even in large quantities. Its deficiency leads to bleeding disorders and other health problems.
