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

Vitamin K is the vitamin of blood coagulation 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 newborns.

Characteristics of vitamin K:

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

Why eat foods rich in vitamin K?

Vitamin K: definition and benefits

Blood coagulation

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

Bone health

Vitamin K ensures the health and strength of bone mineral mass. It supports the action of osteocalcin, an important protein for calcification of bone tissue. At all stages of life, a good supply of vitamin K is essential to promote the growth and renewal of bone tissue. It also helps to 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 found mainly in foods of plant origin and K2 in foods of animal origin.

20 foods that are sources of vitamin K

Foodstuffs Portions of food (µg)
Cabbage, cavalier or curly, cooked 1/2 cup 442-561 µg
Boiled spinach 1/2 cup 469-543 µg
Turnip, dandelion and beetroot leaves, boiled 1/2 cup 280-368 µg
Boiled Swiss chard 1/2 cup 303 µg
Cooked broccoli 1/2 cup 169 µg
Lettuce mesclun 1 cup 154 µg
Raw spinach 1 cup 153 µg
Raw Scarole 1 cup 122 µg
Cooked Brussels sprouts 4 cabbages (80 g) 118 µg
Cooked broccoli 1/2 cup 86-116 µg
Curly lettuce 1 cup 103 µg
Red lettuce 1 cup 82 µg
Asparagus, raw or cooked 1/2 cup 48-76 µg
Fresh parsley 15 ml (1 tablespoon) 62 µg
Boston and Roman lettuce 1 cup 60-61 µg
Cabbage, raw or cooked 1/2 cup 39-55 µg
Kiwi 1 large (90g) 37 µg
Gombos (okras), boiled 1/2 cup 34 µg
Chinese cabbage, raw or boiled 1/2 cup 30-31 µg
Raw green beans 1/2 cup 29 µg

How to use vitamin K properly?

Use of vitamin K

Vitamin K requirements

Adequate Intake (AI)
Babies 0-6 months 2 µg
Babies 7-12 months 2.5 µg
Babies 1-3 years old 30 µg
Children 4-8 years old 55 µg
Boys 9-13 years old 60 µg
Girls 9-13 years old 60 µg
Boys 14-18 years old 75 µg
Girls 14-18 years old 75 µg
Men 19-50 years old 120 µg
Women 19-50 years old 90 µg
Men 50 years and over 120 µg
Women 50 years and over 90 µg
Pregnant women 90 µg
Nursing Women 90 µg

Vitamin K in babies

Vitamin K supplementation for babies is very common, if not systematic. It compensates for the lack of intake through breast milk and non-existent reserves in the newborn. Thus, this supplementation limits the risk of haemorrhagic disease in the first months of life.

Vitamin K dietary supplements

Dietary supplements containing vitamin K are particularly recommended to prevent osteoporosis and cardiovascular disease related to calcification of blood vessels. The competent authorities recommend that the dosage of 25 micrograms per day should not be exceeded to avoid the risk of overdose, the long-term consequences of which are not yet known.

Adverse effects of vitamin K

Vitamin K deficiency

Vitamin K deficiency in adults is extremely rare, newborns are the most at risk. A deficiency can lead to hemorrhagic disease in the baby and abnormal bone growth. In adults, the main medium-term risk is hemorrhagic. In the long term, bone demineralization and the development of disorders such as osteomalacia or osteoporosis can be observed.

Is too much vitamin K dangerous for your health?

There are no scientific studies proving the harmful effects of an excess of vitamin K. However, as a precaution, 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-vitamins K). Also, there is a decrease in vitamin K levels with 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 vitamin K production. In case of anti-vitamin K treatment, it is therefore advisable to limit the dietary intake of this vitamin. On the contrary, in the case of prolonged antibiotic therapy, it may be worth considering supplementation.

Chemical properties

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

There are 3 vitamin K vitamins, 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 intestines 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, it can cause significant side effects (nausea, headache, anemia, etc.).

History of the event

History of the nutrient

It was in the early 1920s that the Danish biochemist C. Dam will make the accidental discovery of vitamin K. At that time, while conducting cholesterol studies, he noticed that chickens deprived of fat were suffering from bleeding. This is how he discovered the presence of vitamin K (for Koagulation in German), a molecule responsible for blood coagulation.

Fifteen years later, he was able to purify vitamin K from alfalfa and then chemically synthesize it with the help of E. Doisy. In 1943, a Nobel Prize in Medicine was awarded to C. Dam and E. Doisy for their discoveries about vitamin K.