role in coagulation, where to find it?

Vitamin K for “Koagulation” is essential for blood clotting. There are three forms: vitamin K1, K2 and K3 (medication). What is it for ? What is the risk if we are deficient? In what foods can you find it? What are its other health benefits? Everything you need to know about vitamin K.

Vitamin K is essential for producing proteins capable of regulate blood clotting. The deficiencies are common, especially in very young child. Unlike other vitamins such as vitamin D, vitamin K can be produced by the body. Where do we find it? In what foods? How much should you consume per day? Lighting.

Definition: what is vitamin K?

Vitamin K is a vitamin fat soluble (soluble in fat), just like vitamins A, D and E. It exists mainly in two forms: vitamin K1 (phytomenadione, phylloquinone or phytonadione) and vitamin K2 (menaquinones). She is provided both by food, especially the green vegetablesand by the intestinal flora (intestinal bacteria allow the synthesis of vitamin K). Vitamin K1 is more directly involved in the coagulation process, while K2 acts more on the calcification of soft tissues. There exists a third form (vitamin K3), synthetic, found in medications, supplements or multi-vitamin supplements.

Why is it called “vitamin K”?

Its name comes from the German “Koagulation“as it participates in the blood clotting mechanism.

In which foods can you find vitamin K?

If the body produces vitamin K, it is not enough to meet the daily requirement. It is therefore interesting to favor foods rich in vitamin K. As a priority: dark green vegetables like spinach, broccoli, kale, and asparagus, as well as vegetable oils (olive, rapeseed, soy, etc.). We also find a little fermented milk products (ripened cheeses, yoghurts, milk, kefir), fish offal and oils.

List of foods rich in vitamin K1 (contents taken from the ANSES Cliqual table):

  • Kale (817 µg per 100g)
  • Watercress (541 µg per 100g)
  • Spinach (482 µg per 100g)
  • Chard (327 µg per 100g)
  • Broccoli (141 µg per 100g)
  • Rapeseed oil (71 µg per 100g)
  • Olive oil (60 µg per 100g)

List of foods rich in vitamin K2 (contents taken from the Cliqual table of ANSES):

  • Goose liver (369 µg per 100g)
  • Chicken thigh (34.3 µg per 100g)
  • Edam (34.3 µg per 100g)

What foods are low in vitamin K?

The foods with the lowest vitamin K content (less than 1 µg per 100g) are cow’s milk, yogurts, corn, white bread, potatoes, peanuts, mushrooms, turnips, cucumbers… .

Fruits lowest in vitamin K are: melon, watermelon, orange, pomelo, mango.

What are the daily vitamin K requirements for men and women?

  • Male : 1 μg/kg body weight/d
  • Women : 1 μg/kg body weight/d

What are the benefits of vitamin K?

Vitamin K is essential to the blood clotting process by allowing the manufacture of certain factors of this coagulation in the liver. She is also involved in the bone metabolism. “At any age, it is essential to have a good supply of vitamin K to promote the growth and then the renewal of bone tissue”assures Professor Luc Christiaens, head of the Cardiology department at the University Hospital of Poitiers. “She also plays a important role in bone mineralization: it is also proposed in the prevention of osteoporosis.”

Many anticoagulant treatments block the activity of vitamin K.

What is its role in coagulation?

Vitamin K is primarily known for its key role in blood clotting (and more specifically vitamin K1). She prevents bleeding by activating many coagulation factors. It is therefore essential in the event of a cut or scrape to stop bleeding.

Vitamin K in infants

Vitamin K supplementation is systematically given to newborns in the maternity ward. It thus makes it possible to compensate for the non-existent vitamin K reserves of the infant. This intake limits the risk of haemorrhage in the first months of life.

Vitamin K and breastfeeding

To prevent the risk of bleeding (which fortunately remains rare), doctors prefer to systematically supplement infants with vitamin K from birth and throughout the duration of exclusive breastfeeding.

What are the risks in the event of a deficiency?

“The sufficient daily intake varies according to age and sex: 30 to 75 mcg between 1 and 18 years, 90 mg in adult women and 120 mcg in adult men. This vitamin K is stored in the liver to several months“, explains our doctor. Therefore, the Vitamin K deficiencies are rare in adults. Nevertheless, they can appear during chronic diseases of the intestine, liver cirrhosis or taking certain medications. They will then cause a blood clotting failure (hypoprothrombinemia). This translates into bruisesfrom nose bleeds, from heavy periods and an bone fragility.

Vitamin K and drugs

Many anticoagulant treatments (vitamin K antagonists) act in blocking the activity of vitamin K.

“In case of vitamin K antagonist treatment, patients are advised to limit their intake of vitamin K-rich foods and avoid taking food supplements containing them” assures our interlocutor. A decrease in vitamin K level should also be reported in the event of prolonged antibiotic therapy. Indeed, antibiotics by partially destroying the intestinal flora reduce the production of vitamin K. “In this case, it may be interesting to consider supplementation” concludes the professor.

Thanks to Professor Luc Christiaens, head of the Cardiology department at the University Hospital of Poitiers. Statements collected in 2020.

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