Vitamin K: where to find it and how to use it?

Vitamin K is the blood clotting vitamin par excellence. In addition to its anti-hemorrhagic role, it also helps to preserve the health of bone tissue. 

There are several forms of vitamin K, one synthesized by plants and the other by bacteria in the intestinal flora of humans and animals. Although very rare in adults, vitamin K deficiency is common in newborn babies.

Characteristics of vitamin K:

  • There are three forms of vitamin K: K1, K2, and K3
  • Vitamin K1 is of vegetable origin, K2 of animal origin, and K3 is synthetic
  • Allows blood coagulation and maintenance of bone tissue
  • Supplementation is strongly recommended in newborns to avoid hemorrhagic disease
  • In the case of anti-vitamin K treatment, food intake can be controlled

Why consume foods rich in vitamin K?

Vitamin K: definition and benefits

Coagulation sanguine

Vitamin K allows the synthesis of prothrombin and other proteins responsible for the activation of several coagulation factors. It is the coagulation vitamin par excellence. It limits the risk of hemorrhage.

Bone health

Vitamin K ensures healthy and strong bone mineral mass. It supports the action of osteocalcin, an important protein for the calcification of bone tissue. At all stages of life, a good supply of vitamin K is essential to promote growth and then the renewal of bone tissue. It also helps prevent disorders related to bone demineralization such as osteoporosis.

Foods Rich in Vitamin K

There are two dietary forms of vitamin K: vitamin K1 and vitamin K2. Vitamin K1 is mainly found in foods of plant origin and K2 in foods of animal origin.

20 foods sources of vitamin K

Collard or kale, cooked 1/2 tax      442-561 µg 
Boiled spinach1/2 tax      469-543 µg
Turnip, dandelion, and beet greens, boiled1/2 tax      280-368 µg
Swiss chard cooked1/2 tax      303 µg
cooked broccoli1/2 tax      169 µg
mesclun lettuce1 tax154 µg
Raw spinach1 tax153 µg
Crue escarole1 tax122 µg
Brussels sprouts cooked4 choux (80 g)118 µg
cooked broccoli1/2 tax86-116 µg
leaf lettuce1 tax103 µg
red lettuce1 tax82 µg
Asparagus, raw or cooked1/2 tax48-76 µg
fresh parsley15 ml (1 tbsp)62 µg
Boston and romaine lettuce1 tax60-61 µg
Cabbage, raw or cooked1/2 tax39-55 µg
Kiwi1 large (90g)37 µg
Okras (okras), boiled1/2 tax34 µg
Chinese cabbage, raw or boiled1/2 tax30-31 µg
Raw green beans1/2 tax29 µg

How to properly use vitamin K?

Use of vitamin K

Vitamin K requirements

Babies 0-6 months     2 µg
Babies 7-12 months2,5 µg
Babies 1-3 years old30 µg
Children 4-8 years old55 µg
Boys 9-13 years old60 µg
Girls 9-13 years old60 µg
Boys 14-18 years old75 µg
Girls 14-18 years old75 µg
Men 19-50 years old120 µg
Women 19-50 years old90 µg
Men 50 and over120 µg
Women 50 and over90 µg
Pregnant women90 µg
Nursing women90 µg

Vitamin K in babies

Vitamin K supplementation in babies is very common, even systematic. It makes it possible to compensate for the lack of intake via breast milk and the non-existent reserves of the newborn. Thus, this supplementation limits the risk of hemorrhagic disease in the first months of life.

Vitamin K food supplements

Food supplements containing vitamin K are particularly recommended to prevent osteoporosis and cardiovascular diseases linked to the calcification of the vessels. 

The competent authorities recommend not to exceed the dosage of 25 micrograms per day to avoid the risk of overdose, the long-term consequences of which are still unknown.

Adverse effects of vitamin K

Vitamin K deficiency

Vitamin K deficiency in adults is extremely rare, newborns are most at risk. A deficiency can lead to hemorrhagic disease in the baby as well as abnormalities in bone growth. 

In adults, the main medium-term risk is bleeding. In the long term, it is possible to observe a demineralization of the bone and the occurrence of disorders such as osteomalacia or osteoporosis.

Is too much vitamin K dangerous for health?

There is no scientific study proving the deleterious effects of an excess of vitamin K. As a precaution, however, it is recommended to seek the advice of a doctor before considering drug supplementation with this vitamin.

Vitamin K and anticoagulant treatments

Vitamin K interacts with anticoagulant treatments (anti-vitamin K). Also, there is a decrease in vitamin K levels in case of prolonged antibiotic treatment. Indeed, a small part of vitamin K is synthesized by the bacteria present in the intestinal flora. 

However, antibiotics weaken these bacteria and can therefore induce a significant decrease in the production of vitamin K. In the event of anti-vitamin K treatment, it is, therefore, advisable to limit the dietary intake of this vitamin. 

On the contrary, in the event of prolonged antibiotic therapy, it may be interesting to consider supplementation.

Chemical properties

There is no vitamin K but vitamin K forms a group of fat-soluble vitamins. They are essential for blood coagulation and the mineralization of bone tissue.

There are 3 vitamins K, all belonging to the quinone family. Vitamin K1 (phylloquinone) is only synthesized by plants. It is therefore found in foods of plant origin (cabbage, leafy green vegetables, etc.). Vitamin K2 (menaquinone) is synthesized by bacteria in the gut of mammals. it is found in foods of animal origin. 

Finally, vitamin K3 (menadione) is a synthetic form. Today, it is no longer used in human food. Indeed, being three times more active than other forms of vitamin K can cause significant side effects (nausea, headache, anemia, etc.).


Nutrient history

It was at the beginning of the 1920s that the Danish biochemist C. Dam made the fortuitous discovery of vitamin K. At the time and while he was carrying out studies on cholesterol, he realized that chickens deprived of lipids suffer from bleeding. This is how he discovered the presence of vitamin K (for Koagulation in German), the molecule responsible for blood coagulation.

Fifteen years later, he succeeded in purifying vitamin K from alfalfa and then chemically synthesizing it with the help of E. Doisy. In 1943, a Nobel Prize for Medicine will be awarded to C. Dam and E. Doisy for their discoveries about vitamin K.

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