Vitamin K - where it occurs, what it helps, deficiency symptoms

Did you know the role that ... chickens played in the discovery of vitamin K? Many of them sacrificed their health so that today we understand what vitamin K is and how important it is for our bodies.

In this article, I will introduce you to the somewhat surprising history of the discovery of vitamin K and, together with Dr. Witold Tomaszewski, M.D., I will introduce you to the functions, best sources and symptoms of deficiency of this vitamin. After reading the article, you will become better acquainted with the "coagulation vitamin" and develop a taste for... salad.

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Natu.Care Vitamin D 2000 IU

Natu.Care Vitamin D 2000 IU supports the normal function of the immune system, the maintenance of healthy bones and teeth, and the normal function of the heart, kidneys and muscular system.

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Great product, the tablets are small and easy to swallow. Extra points for the high quality!

Joanna

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See also:

• Vitamin K2 [action + deficiency symptoms]
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• Vitamin D3 K2 [whether you need to combine + expert opinion]
• Vitamin D3 drops [ranking + use + expert opinion]
• Vitamin K2 [properties + occurrence]
.
• Best vitamin D3 [ranking + expert opinion]
.
• Vitamin D deficiency [symptoms + treatment]
.
• Vitamin D [dosage + standards and recommendations]
.
• Vitamin D overdose [symptoms + effects + what to do]
.
• What is vitamin D? [sources, table, examples]
.
• Maximum dose of vitamin D [what + expert opinion]
.

Interesting circumstances of the discovery of vitamin K

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In 1929, Danish scientist Henrik Dam studied and the process of cholesterol  metabolism in the body by feeding chickens a fat-free diet. After a few weeks, the animals began to suffer from bleeding in the subcutaneous tissue, muscles or organs. 

Adding cholesterol to the diet did not help, so Dam postulated that - in addition to fat - there must be another compound in the diet to prevent bleeding. Haemorrhages in chickens regressed when alfalfa, spinach or cabbage were included in the diet (they have a high vitamin K content).

Following further research, he found a factor in hemp seeds that prevented bleeding and decided to call it the clotting vitamin. In German, it was labelled "coagulation vitamin" (coagulation) and so the new vitamin was given the letter K.

The new vitamin was named vitamin K.

Vitamin K - properties

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It is one of the 4 vitamins  fat-solubleand, along with the vitamins A, D and E. Vitamin K is actually a group of 3  organic chemical compoundsand.

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In this group are:

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• Vitamin K1 (phylloquinone)
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It is  synthesised  by plants - found in green leafy vegetablesand. It is the main source of vitamin K in the diet of  Europeansand.

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• Vitamin K2 (menaquinone)
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It is mainly found in meat, cheese and eggs. It is also produced by the bacteria that make up our intestinal flora of the digestive system. The synthesis of this vitamin by the microorganisms found in the jejunum and ileum, covers a significant part of the daily requirement for vitamin K.

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• Vitamin K3 (menadione)
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Synthetic form of vitamin K, acting as a provitamin (a chemical compound that is converted into a vitamin in the body under the influence of enzymes or sunlight). It is used as a haemostatic drug.

What does vitamin K help with?

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Vitamin K affects several important processes in our body. 

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• Helps the  cardiovascular system  by strengthening blood vessel wallsand.
• Participates in the formation of proteins needed for  proper clotting   of blood.
• Along with osteocalcin, has  effects on the production of  healthy bone tissue .
• Helps  the calcification of bone tissue  by the skeletal system, participating in the formation of bone tissue .
• Strengthens the immune system .

Scientists  are also looking at the likely properties of vitamin Kand. The work is ongoing, and the researchers are particularly interested in the role of vitamin K:

• as a protective factor in the development of liver cancer and in reducing the risk of death in patients with cirrhosis and cancers originating from hepatocytes (the cells that make up the liver),
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• in its ability to increase the sensitivity of target tissues to insulin,
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• in reducing the risk of the onset and development of coronary heart disease.
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Wish, Vitamin K2 MK-7

4.8

WISH Vitamin K2 MK‑7 from Natto – quick overview

• Active ingredients:
  100 µg of vitamin K2 in the form of MK‑7 (menaquinone-7) from fermented Natto in one tablet

• For whom and why?
  For adults – supports bone health, circulatory system and proper mineralisation due to increased bioavailability of K2 MK‑7

• Form:
  Option: plant-based tablets (probio) – well tolerated and easy to take

• Daily dosage:
  1 tablet daily, preferably with a meal containing fats

• Sufficient for:
  120 days of use (1 tablet daily)

Check Price

Product Description

Dietary supplement containing vitamin K, which contributes to normal blood clotting, helps maintain healthy bones, and supports the body's proper immunity. 

Pros and Cons

Pros:

• MK-7 form (menaquinone-7) – longer action time and better absorption than K1

• Natto origin (fermented soy) – a natural source, rich in MK-7

• Low daily dose (100 µg) – safe and beneficial for most people

• Plant-based tablet – suitable for vegans, easy to swallow

• Long packaging – a 4-month treatment sufficient for an extended period

Cons:

• Not suitable for individuals taking anticoagulants (e.g., warfarin) — consultation with a doctor is required

• Effects of supplementation (e.g., strengthening bones) visible only after several weeks

• This product is a supplement — it does not replace a balanced diet and medical treatment

• Not tested on children and pregnant women — not recommended without consulting a doctor

Yango Витамин K2-MK-7

4.8

• Активни съставки:
  200 µg витамин K2 под формата на менахинон-7 (MK-7) в една растителна капсула

• За кого и за какво?
  За възрастни – подпомага нормалното съсирване на кръвта, здравето на костите и сърдечно-съдовата система; полезен в ежедневната добавка или профилактика

• Форма:
  Вегетариански капсули (микрокристална целулоза, растителна обвивка)

• Дневна доза:
  1 капсула веднъж дневно, най-добре по време на хранене, съдържащо мазнини, с вода

• Достатъчно за:
  90 дни употреба (1 капсула дневно)

Провери цената

Описание на продукта

Yango Витамин K2-MK-7 е хранителна добавка в капсули, предназначена за разнообразяване на ежедневната диета на възрастни.

Плюсове и минуси

Плюсове:

• Висока доза MK‑7 (200 µg) – осигурява достатъчно добавяне

• Висока бионаличност и дълго действие благодарение на формата MK‑7

• Вегетарианска капсула – не съдържа животински съставки

• Продукт без изкуствени добавки: без консерванти, оцветители, алергени (соя, глутен, лактоза, ядки, риба, яйца)

• Икономична опаковка – 90 дни лечение в една кутия

Минуси:

• Неподходящ за хора, приемащи антикоагуланти – необходима е консултация с лекар

• Ефектите (например, подкрепа на минерализацията на костите) изискват редовна употреба и са видими след няколко седмици

• Не се препоръчва за деца, бременни жени и кърмещи без медицинска консултация

• Хранителна добавка – не замества диета или медицински терапии

Swanson K2

4.9

• Active ingredients:
  100 µg of vitamin K2 in the form of menaquinone-7 (MK-7) derived from Japanese natto, enclosed in a soft capsule with sunflower oil

• Who is it for and why?
  For adults – supports bone health and cardiovascular system, helps direct calcium to bones and prevents its deposition in arteries

• Form:
  Soft capsules (softgels), 30 pieces

• Daily dose:
  1 capsule daily, with a meal containing fat, taken with water

• Lasts for:
  Monthly supplementation – 30 days

Check Price

Product Description

Swanson K-2 is a dietary supplement in the form of gel capsules with a high content of vitamin K. Each capsule contains 100 µg of naturally sourced vitamin K in the form of menaquinone-7 (vitamin K2 MK-7) from natto.

Pros and Cons

Pros:

• Natural form K2 MK-7 – longer action and better absorption than K1

• Combination of vitamin from natto and sunflower oil – supports bioavailability and stability

• Vegan, gluten-free, lactose-free, non-GMO and free from artificial colours

• Supports proper blood clotting and bone mineralisation – promotes arterial flexibility

• Highly researched formula appreciated by users, confirming improvement in well-being and bone condition

Cons:

• Not suitable for individuals on anticoagulant medication (e.g. warfarin) – medical consultation required

• Effects work gradually – requires regular use over several weeks

• Supplement, not a medicine – does not replace therapy and requires a complementary diet

• One month supply – longer treatment will require purchasing additional supplements

Progress Labs Vitamin K2 MK-7 from Natto Forte 100 µg

4.9

• Active ingredients:
  100 µg of vitamin K2 (MK-7) derived from natural fermented natto (Bacillus subtilis) in one tablet.

• Who is it for and why?
  For adults – supports bone health, cardiovascular system, and proper blood clotting through effective calcium utilisation.

• Form:
  Vegetarian tablets, non-GMO and free from artificial additives.

• Daily serving:
  1 tablet daily, preferably with a meal containing fats.

• Sufficient for:
  120 days of daily supplementation.

Check Price

Product Description

Progress Labs Vitamin K2 MK-7 with Natto Forte 100 µg is a dietary supplement in tablet form with a high content of vitamin K.

The preparation is made using menaquinone-7 obtained through the fermentation of soy using the Bacillus subtilis natto strain. Vitamin K contributes to normal blood clotting. Additionally, this ingredient is necessary for maintaining healthy bones.

The package contains 120 tablets with natural vitamin K, allowing for 4 months of daily supplementation of this valuable active ingredient for bone health.

Pros and Cons

Pros:

• Natural MK-7 derived from natto – high bioavailability and long-lasting effect

• Dosage of 100 µg provides 133% NRV – optimal support without excess

• Vegan formula, non-GMO, sorbitol-free, and preservative-free – pure composition

• Supports healthy bones and circulation by directing calcium where it is needed

• Large package – a four-month supply in one package

Cons:

• Requires consultation when using anticoagulant medications

• Effects of supplementation visible only after several weeks of regular use

• Supplement, not a medicine – does not replace diet or specialised treatment

• Pregnant and breastfeeding women and children should use with medical consultation

 

SFD K2-100

4.8

• Active ingredients:
  100 µg of vitamin K2 in the form of MK-7 derived from fermented natto – one package contains 90 tablets.

• Who is it for and why?
  For adults – supports bone health, proper blood clotting and prevents calcium deposition in blood vessels, especially with an active and healthy lifestyle.

• Form:
  Tablets (plant-based coating), one daily portion lasts for 90 days.

• Daily portion:
  1 tablet daily, taken with water, preferably with a meal containing fats.

• Sufficient for:
  90 days of daily use.

Check Price

Product Description

Vitamax K2-100 is a dietary supplement with a high content of vitamin K of natural origin. In the recommended daily portion of the product, there is 100 µg of the active ingredient, which helps in the proper functioning of the human body by:

• participating in the process of proper blood clotting,
• supporting bone health.

The product has been developed with adults in mind, particularly those who are physically active.

Pros and Cons

Pros:

• Natural form MK-7 derived from natto – well absorbed and stable in the body

• Supports bone mineralisation and proper clotting process

• Bioactive form ensures effective action throughout the body

• Vegan, non-GMO, gluten-free, lactose-free, preservative-free, and dye-free

• Large packaging – economical and convenient for 3 months of supplementation

Cons:

• Requires consultation when using anticoagulant medications (e.g., warfarin)

• Effects appear gradually – regular use is needed (several weeks)

• Dietary supplement – does not replace a balanced diet or medical treatment

• Not intended for children, pregnant or breastfeeding women without medical advice

K2-Vitum Forte 75 µg

4.9

• Active ingredients:
  75 µg of vitamin K2 in the form of menaquinone-7 (MK-7) and ~193 mg of cold-pressed flaxseed oil (including ~97 mg ALA) in each capsule.

• Who is it for and what for?
  For adults – vitamin K2 supplementation supporting bone health, proper calcium metabolism, and blood clotting processes.

• Form:
  Soft capsules in flaxseed oil.

• Daily portion:
  1 capsule daily, preferably with a meal.

• Lasts for:
  60 days of use (1 package).

Check Price

Product Description

Oleofarm K2-Vitum Forte 75 µg is a dietary supplement with a high content of vitamin K. The formula is suitable for use as a supplement to the daily diet of adults seeking an additional source of vitamin K.

Pros and Cons

Pros:

• Natural MK-7 – high bioavailability, long-lasting effect

• Flaxseed oil supports absorption and provides omega-3 (ALA)

• Vegan and pure formula – free from preservatives, GMOs, gluten, and lactose

• Convenient softgel form – easy to swallow and use

• Good portion-to-price ratio

Cons:

• Taking anticoagulants requires consultation with a doctor

• Bone strengthening and coagulation effects appear after weeks of regular use

• The product is a supplement – it does not replace diet or treatment

• Not recommended for pregnant or breastfeeding women and children without medical consultation

Where is vitamin K found? Best sources

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Daily vitamin and mineral requirements are best met with a balanced and varied diet. Find out where you can find the most vitamin K - compose a meal that is tasty and rich in this vitamin.

Productsand rich in vitamin K1 (values given per 100 g):

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It is worth adding spices to your dishes not only to enhance their flavour and aroma - they are also real vitamin K bombs.

Best sources of vitamin K2and  (values quoted per 100 g):

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

From the whole combination, you can compose a very tasty and valuable salad rich in vitamin K1 and K2. Do you have an idea? Leave it to me in a comment below the article, I'd be happy to try it.

Vitamin K deficiency - symptoms

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Vitamin K deficiency is rare in  adult individualsand. The daily requirement is largely covered by the synthesis of vitamin K2 by the intestinal microflora, and the rest is supplemented by vitamin K1 supplied with food.

Deficiency usually results from disorders in the process  digestion or absorptionand in the gastrointestinal tract and in adults may manifest as:

• prolonged wound healing time, 
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• haemorrhages, 
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• easy formation of bruises,
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• disorders of the bowel,
• frequent diarrhoea,
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• frequent diarrhoea,
• reduced immune function,
• diarrhoea.
• lower immune function,
• heavy menstrual periods
• abundant menstruation in women,
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Infants are at risk of vitamin K deficiency due to incompletely formed intestinal flora and low vitamin K content in breast milk.

Nevertheless, infants are at risk of vitamin K deficiency.

Vitamin K2 deficiency in infants can be manifested by:and

• bleeding from the site where the umbilical cord was removed,
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• bleeding in the skin, nose, gastrointestinal tract or elsewhere,
• bloods from the skin, nose, gastrointestinal tract or other areas.
• bleeding from the penis (if the child has been circumcised),
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• increased bleeding into the brain,
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The Polish Neonatal Society  recommends vitamin K supplementation for infantsand. All newborns should receive vitamin K (usually by injection) within the first 5 hours of life.

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Effects of vitamin K deficiency

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Unmedicated vitamin K deficiency can lead to:

• disorders of blood clottingand,
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• increased risk of cardiovascular disease ,
• osteoporosis ,
• vascular calcification  (calcification),
• haemorrhages ,
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• hepatitis ,
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Remember - vitamin K deficiency is rare. It's good to be aware of the symptoms of deficiency, but if you take care of a varied diet and don't have problems with your digestive function - don't worry about a deficiency of this vitamin.

Vitamin K excess - is it possible?

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Vitamin K overdose occurs  rarelyand. Symptoms of overdose  reported in the literature  include: feeling hot, excessive sweating, breakdown of red blood cells and symptoms of haemolytic anaemia.

The toxicity of  vitamin K usually involves menadione, a synthetic vitamin K3and. 

Daily vitamin K requirements

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Because of insufficient evidence regarding the function, absorption and occurrence of menaquinones (vitamin K2) in humans, standards have been set only for phylloquinone (vitamin K1).

Standards for vitamin Kand for Poland, set at adequate intake (AI)*

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*AI  (Adequate Intake) is a dietary recommendation used when there is insufficient data to calculate average intakeand.

See also articles on health:

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• Blood tests [how often to do them + how to prepare] 
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• Cortisol testing [standards + price]
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• Thyroid tests [which ones to perform + norms + results]

Contraindications and precautions

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The use of vitamin K requires  precautionsand  u:

• newborns, 
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• patients with renal impairment,
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• patients with hereditary hypoprothrombinemia (prothrombin - blood clotting factor deficiency),
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• patients with excessive anticoagulation,
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• patients with hypersensitivity to vitamin K,
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Pregnant and breastfeeding women should consult a physician before supplementation.

See also other articles on vitamins and minerals:

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• Vitamin B12 deficiency [causes + symptoms + treatment]
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• Vitamin D deficiency [symptoms + treatment]
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• Potassium [deficiency + norm + what it's in]
• Zinc [properties + deficiency + excess]
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• Iron [properties + sources + deficiency]
• Selenium [properties + dosage + supplementation]
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• Iodine [properties + dosage + deficiency symptoms]
.

Do you know any other interesting facts about vitamin K? Share them in the comments. I'd love to read about them while I'm eating my greens.

Summary

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