Everything you need to know about vitamin K



Emily Condon
BSc (Hons) Biological Sciences

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What is vitamin K?

Vitamin K refers to a group of fat-soluble vitamins that play a role in blood clotting as well as regulating blood calcium levels and bone metabolism. In the liver, vitamin K is required to produce 4 factors that are necessary for blood to properly clot: prothrombin and also factors VII, IX, and X.

How do we get vitamin K?

The majority of people get all the vitamin K they need by eating a varied and balanced diet. Because vitamin K is a fat-soluble vitamin, any vitamin K in the body that is not needed immediately is stored in the liver for future use. The healthy bacteria that live in the digestive system can produce vitamin K. 

Green leafy vegetables including broccoli and spinach, vegetable oils and fortified cereals are all good sources of Vitamin K. Small amounts can also be found in chicken and dairy products. Vitamin K supplements are also available but monitoring the dose is important as too much can be harmful, so it is advised you speak with your doctor before supplementing vitamin K.

What are the symptoms of a vitamin K deficiency?

Vitamin K deficiency is rare, but can lead to problematic blood clotting and increased bleeding. In those who eat a healthy, varied diet, achieving a vitamin K intake low enough to alter standard clinical measures of blood coagulation is extremely rare. Common symptoms of a vitamin K deficiency include bleeding from the nose and gums, heavy periods, slow wound healing and easy bruising. 

People at risk for developing a vitamin K deficiency include those with chronic malnutrition (such as those who are dependant on alcohol) or conditions that limit absorption of dietary vitamins such as biliary obstruction, celiac disease, ulcerative colitis, regional enteritis, cystic fibrosis, short bowel syndrome, or intestinal resection. Vitamin K deficiency is most common in newborns and can occur during the first few weeks of infancy due to low clotting factor levels, and low vitamin K content of breast milk. Because of this, a dose of vitamin K given to newborn’s is standard in the UK. 

Learn more about vitamins:

What are vitamins?

Everything you need to know about vitamin A

Everything you need to know about the B vitamins

Everything you need to know about vitamin C

Everything you need to know about vitamin D

Everything you need to know about vitamin E

Medicheck your vitamin K level

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