Vitamin K Deficiency

General text about the lack of vitamins can be found here.


Vitamin K is one of the fat-soluble vitamins, which is especially important for proper blood clotting. It is quite a special vitamin as it is not only taken in foods, but it is produced in our body by intestinal bacteria. In foods, it is present in larger quantities mainly in green vegetables (kale, cabbage, spinach, broccoli, etc.).


The lack of vitamin K is not typical in otherwise healthy individuals thanks to the combination of food intake and intestinal microflora production. The deficiency may occur in patients with impaired nutrient absorption and in patients chronically treated with antibiotics that eradicate the intestinal microflora. Vitamin K deficiency often accompanies chronic alcoholism with liver cirrhosis. And it may be also present in newborn babies whose intestines have not been yet populated by bacteria.


Vitamin K plays significant role in the formation of protein substances that play role in the process of blood coagulation. These proteins are produced in healthy liver tissue. Therefore, the lack of vitamin K disrupts blood clotting and it may manifest with increased risk of bleeding including bruising, nosebleeds, bleeding gums, blood in stool, blood in urine, etc.


It should be noted that vitamin K strongly interferes with an anticoagulation drug known as warfarin. Newly administered warfarin may cause decrease of vitamin K level and on the contrary, increased intake of vitamin K may decrease warfarin effects. That is why warfarinized patients should avoid food with increased amount of vitamin K.


We do not directly measure the level of vitamin K in blood, but we can deduce its amount in body from some blood clotting tests. The most valuable is PT (prothrombin time) test that depends on coagulation factors produced in presence of vitamin K. The PT test is also commonly used to monitor the effectiveness of warfarin.


Vitamin K may be easily supplemented. There are many drugs containing vitamin K that may be given orally or intravenously. Few drops of vitamin K solution are usually administered to newborns as they usually suffer from the lack of vitamin K. In internal medicine, vitamin K serves as an antidote to patients with bleeding complications due to warfarin overdose or to patients with liver cirrhosis.


Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Sources: basic text sources