What vitamin K For? Vitamin K Rich Foods, Foods With vitamin K 2 Benefits Vitamin K Rich Foods

What is Vitamin K Deficiency? How Many Vitamins Take Per Day?

Vitamin K is an essential nutrient for the body, as it performs several functions, such as participating in the blood clotting process, avoiding hemorrhages, and stimulating calcium fixation in bones, being important for bone strengthening and to prevent osteoporosis.

vitamin k rich foods
vitamin k rich foods

The main form of vitamin K is vitamin K1, also called phytoquinone, and is found mainly in dark green vegetables such as broccoli, kale and spinach, in addition to some fruits such as kiwi, strawberry and grapes, for example. In addition, vitamin K2 is produced by the intestinal microbiota and is present in some foods of animal origin. 

Vitamin-K is a fat-soluble (fat-soluble) vitamin. Its name comes from the German Koagulation, an allusion to the role it plays in blood clotting. There are two main forms of this vitamin: phytomenadione, or vitamin-K1, which comes mainly from green vegetables, and menaquinone, or vitamin K2, which is produced by bacteria in the colon or appears in certain foods as a result of a fermentation process (cheese, miso, natto, etc.). Vitamin K1 is more directly involved in the coagulation process, while K2 acts more on soft tissue calcification.

History Of Vitamin K

It was in the early 1920s that the Danish biochemist C. Dam made the fortuitous discovery of vitamin-K. At the time and while conducting studies on cholesterol, he realized that chickens deprived of lipids suffered from hemorrhages. This is how he discovered the presence of vitamin-K (for Koagulation in German), a molecule responsible for blood clotting.

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

History of vitamin K1 and K2

Vitamin K1 was first isolated from alfalfa. Two biochemists, the Danish Henrik Carl Peter Dam and the American Edward Adelbert Doisy, shared the Nobel Prize in Medicine or Physiology in 1943 for their discoveries on vitamin K, a clotting factor.

Vitamin K2 was then detected in fermented fish meal. It has also been discovered that our own colon produces this same molecule when its intestinal flora is healthy and abundant.

Japanese researchers have developed a natto (pressed and fermented soybean) called “functional”. This product is made by fermenting soy with a strain of bacteria specially selected for its ability to produce good amounts of vitamin-K2. Within a program on foods for specific medicinal use (FOSHU), implemented by the Japanese Ministry of Health, there is no hesitation in stating that this natto can help prevent osteoporosis. In Japan, a particular form of vitamin K2 (MK-4) is a recognized treatment for osteoporosis.

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What is the difference between vitamin K1, K2 and K3?

Types of Vitamin-k and Their functions: 

  • Vitamin K1(phyllizinone) is fat soluble. Therefore, the vitamin in the blood dissolves along with fat in the food. It is vitamin K1 that affects the blood’s ability to clot. You consume vitamin K1 through your diet. Which foods contain vitamin-K1, you can read more about further down.
  • Vitamin K2 (menaquinone) affects calcium metabolism, as well as maintains bones. It is also through vitamin K2 that you form the proteins that ensure that calcium can be deposited in the bone tissue. Vitamin K2 is formed from the vitamin-K1 you have in the intestine, which is absorbed in the small intestine. Therefore, it is of course important that your intestinal flora is well-functioning in order to be able to convert enough vitamin-K2.
  • Vitamin K3 is a synthetically produced vitamin (menadione). K3 is therefore not natural, which does not make it a vitamin in itself. But it has a similar vitamin K effect as well as being water soluble.

Min K2 is the more active form of the vitamin, both variants would achieve the same effect in the body. Others believe that the much rarer vitamin K2 is crucial for our health.

Chemical Properties Of Vitamin K

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

There are 3 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 mammalian gut. 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.).

Knowledge About vitamin K

The vitamin’s name (k) derives from coagulation, which is the blood’s ability to clot. The vitamin was actually found by the Danish biochemist Henrik Dam in 1935. After that, we have only learned more about the vitamin.

Vitamin K contributes to the normal clotting process of the blood. In addition, vitamin-K contributes to your body’s bone formation.

What is vitamin K good for?

Vitamin K is a fat-soluble vitamin that comes in several forms. Among other things, vitamin-K1 (Fyllikinon), which is mainly found in green plants, vitamin-K2 (Menaquinone), which is produced by bacteria in the intestine and is found in animal products – as well as vitamin-K3 (Menadione), which is a synthetic form, and which is the form primarily used in dietary supplements.
Since vitamin K is fat soluble, it is recommended to consume with a meal that contains one or more fat sources, as it helps to ensure the best possible absorption of the vitamin.

Vitamin K deficiency

Vitamin K deficiency in adults is extremely rare, vitamin k for 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 hemorrhagic. In the long term, it is possible to observe demineralization of the bone and the occurrence of disorders such as osteoma Lacia or osteoporosis.

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

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Vitamin K is very important for the body as it performs the following functions:

1. Participates in blood clotting

Vitamin-K is necessary to synthesize proteins that help control bleeding (clotting factors), important for blood clotting, preventing bleeding and favoring wound healing.

2. Maintains bone health

Vitamin K is necessary for the production of osteocalcin, a fundamental protein of the bone matrix, whose function is to stimulate calcium fixation in bones and teeth, being fundamental for normal bone development and its maintenance in adulthood, helping to prevent the development of osteoporosis.

It is important to take into account that in the event that vitamin K contributes to the improvement of bone mass, it is essential to have a good intake of calcium in the diet.

3. Prevents bleeding in the newborn

Vitamin k to newborns: vitamin k newborn. The high risk of the newborn presenting bleeding from vitamin-K deficiency happens because they are born with a very low reserve of this vitamin. This is because vitamin-K does not easily cross the placenta and breast milk is a very poor source of this vitamin, and the baby’s intestine is not yet formed by bacteria capable of producing this vitamin in sufficient amounts. Therefore, in a preventive manner, vitamin K is administered in newborns.

Preterm births, with complications and the consumption of some medications by pregnant women, such as anticonvulsants or anticoagulants, for example, increase the risk of hemorrhage and vitamin K deficiency in the newborn.

4. Promotes cardiovascular health

Vitamin-K is related to the production of proteins that help prevent calcification or hardening of the arteries of the heart, which could contribute to the development of heart diseases such as atherosclerosis and myocardial infarction.

Nutritional references (recommended dietary allowances)


Nutritional reference for vitamin K in micrograms (μg) per day (1)

Children from 1 to 3 years


Children from 4 to 9 years


Children from 10 to 12 years


Adolescents aged 13 to 15


Adolescents aged 16 to 19




Pregnant or breastfeeding women


Persons over 75 years of age


The recommended dietary allowances could be revised upwards. Indeed, the recommendations are currently based on the quantities necessary to obtain an optimal synthesis of coagulation factors. The recent demonstration of vitamin-K requirements for the production of other proteins such as osteocalcin, prompts some researchers to propose higher recommended intakes.

In addition, most health agencies recommend an intake of 1 μg per kilogram of body weight per day. For example, the European Food Safety Authority (EFSA) has set a dietary reference value (average for an adult) of 75 μg per day.2.

Which population groups are at increased risk for insufficient vitamin K intake?

  • Newborns and infants vitamin k in newborns receive a prophylactic vitamin K administration after birth due to insufficient vitamin K transport through the placenta. Thus, the bleeding often observed in the past after birth is preventable.
  • Older people may have an increased need for vitamin K as a result of malabsorption or taking medication.
  • In the age group ofadolescents and young adults (15 to 24 years), the estimated recommended intake of vitamin K is not reached (Nutrition Report 2012).

In these cases, supplementation with vitamin K may be useful.

Food Sources of Vitamin K

The foods richest in vitamin K1 are leafy vegetables (spinach, green salads), various cabbages, soybean and rapeseed oils. Other vegetables and oils, fruits, provide smaller quantities.

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Foods that provide vitamin K2 are mainly animal livers and fermented dairy products (especially cheeses), as well as natto, a traditional Japanese food made from fermented soybeans.

Seaweed is highly concentrated in vitamin K.

Some microorganisms present in the colon produce vitamin K, which seems to be poorly assimilated.2.


Vitamin K intake in micrograms (μg) per 100 g of food (3)



Cooked spinach


Soybean oil


Cooked chard


Curly chicory salad


Raw endive


Green cabbage, Brussels sprouts or cooked broccoli

110 to 140

Lettuce, romaine salad

100 to 130

Rapeseed oil


White cabbage, cooked asparagus, celeriac

60 to 70

Raw heifer liver




Olive oil




Cooked green bean


For example: 30 g of romaine salad (a medium plate) seasoned with 10 g of rapeseed oil (one tablespoon) = 100% of the recommended intake for an adult.

Vegetables as a valuable source of vitamin K

How much vitamin K do we need to stay healthy? There are only estimates. The German Society for Nutrition recommends 70 micrograms of vitamin K per day for men between 15 and 50 years, 60 μg for women.

Table of vitaminK1-containing foods for you:

Food Vitamin Kin μg per 100g edible portion
Broccoli 250
Watercress 250
Fennel 240
Kale 817
Chickpeas 264
Purslane 381
Brussels sprouts 236
Chives 380
Soy flour 200
Spinach 305
Grape seed oil 280

The listed vitamin K foods are plant-based sources of vitamin K1, as K2 is much less common.

Valuable vitamin K2 foods

Some nutrition experts recommend a daily vitamin-K2 intake of 0.5 to 1.0 mcg per kilogram of body weight. Due to the low vitamin-K2 content in our food, this can hardly be achieved through the diet – especially not for vegetarians and vegans, since vitamin K2 is mainly found in animal products. This is where the already mentioned dietary supplements come into play. They promise an optimal supply of vitamin-K2 to prevent health problems. Hans Konrad Biesalski, member of the German Society for Nutritional Medicine, warns in the Aargauer Zeitung:

Vitamin K 2 Benefits

Vitamin k 2 benefits: Vitamin K2 is considered by many to be a super vitamin. That’s because vitamin K2 takes the calcium from the veins and “puts” it into the bones instead. Therefore, the vitamin can help against both atherosclerosis and osteoporosis. In the United States, it is recommended that men consume 120 micrograms of vitamin K2 per day and women 90 micrograms. Vitamin K2 is found in milk, cream, butter and yogurt. It can help against:

  • OSTEOPOROSIS. A study has shown that when postmenopausal women consume 180 micrograms of vitamin K2 every day for three years, they get stronger bones than the control group. Vitamin-K2 should preferably be taken in combination with vitamin D3, because vitamin D3 helps us absorb calcium better.
  • ARTERIOSCLEROSIS. A study from the Netherlands showed that participants who consumed vitamin-K2 diets had healthier blood vessels with less calcification.
  • CARDIOVASCULAR DISEASE. A large study with more than 16,000 participants has shown that participants who consume vitamin K2 diets generally have a lower incidence of cardiovascular disease.
    • CANCER. A research team followed 24,340 healthy people aged 35-65 years through 14 years in a dietary study. The results showed that those who consumed diets with vitamin K2 had less incidence of cancer, specifically lung cancer and prostate cancer.
    • WEIGHT LOSS. New studies from Maastricht in the Netherlands show that vitamin K2 can also help with weight loss. The women who received vitamin K2 supplements received less belly fat and less fat around their internal organs than the women who received placebo.


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Vitamin K – you need to know | Features & Lack | Helsebixen

Vitamin K – read everything you need to know about the vitamin | Med24.dk

Vitamin K – Role and Food Sources (doctissimo.fr).

Food supplement with vitamin K – Lebensmittelverband Deutschland

Vitamin K: what it’s for and recommended amount – Your Health (tuasaude.com)

Vitamin K – Benefits, Sources, Deficiencies, Tips (passeportsante.net)

VitaminK – Vitamins and natural products – Familiprix

Vitamin K2: What is vitamin K2 good for? – ALT.dk


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