Vitamin K2: Benefits, Forms, Dosage, and Why It’s More Important Than You Think

Although vitamin K2 is absolutely essential for maintaining healthy bones and blood vessels and the overall balance of calcium metabolism, it still remains in the shadow of better-known nutrients and is often overlooked, not only by the public but also in official health recommendations. Given its key role in calcium metabolism, vitamin K2 deserves much more attention, both as part of an individual approach to health and in the development of dietary recommendations and prevention strategies. In this article we look at what vitamin K2 is, what forms it comes in, how it works in the body, why it is missing from the modern diet, and how to supplement it correctly.

What will you learn in this article?

1. What is vitamin K2
2. Effects of vitamin K2
3. Vitamin K2 and statins
4. Why is vitamin K2 missing from the modern diet?
5. How can I tell if I am deficient in vitamin K2?
6. How and when to take vitamin K2?
7. Which form of vitamin K2 to choose
8. How much vitamin K2 per day?
9. Don’t forget vitamin K2 in summer
10. Vitamin K2 overdose
11. Conclusion
12. Key takeaways

What is vitamin K2

Vitamin K2 (menaquinone) is one of the fat-soluble vitamins and is a key member of the vitamin K family. Until recently there was little information about vitamin K and it was thought to be a single substance. Extensive studies, however, have shown that vitamin K is a whole group of substances, specifically K1, K2 and K3, each of which comes from different sources and is used by the body in a different way.

• Vitamin K1 (phylloquinone): Found mainly in green leafy vegetables, it serves primarily for proper blood clotting in the liver.

• Vitamin K2 (menaquinone): It has different functions in the body than K1, especially managing calcium. It exists in several forms, the most important of which are MK-4 and MK-7:

  • K2 MK-4: Comes mainly from animal sources (liver, eggs, meat), but is broken down very quickly in the body. To maintain a stable level, it needs to be consumed several times a day.

  • K2 MK-7: Comes from fermented foods (for example the traditional Japanese dish natto or aged cheeses). It has a significantly longer half-life in the human body (up to 72 hours), which ensures a stable level in the bloodstream. In supplements, the MK-7 form (ideally in a pure all-trans configuration) is therefore considered the most effective and most bioavailable.

• Vitamin K3 (menadione): This is a purely synthetic form that can be harmful to the body, which is why its use in human nutrition has been banned. Among other things, it can impair the function of glutathione (one of the strongest antioxidants), which can lead to oxidative damage to cell membranes.

Effects of vitamin K2

While vitamin K1 is primarily involved in blood clotting (activating clotting factors in the liver), vitamin K2 acts in the body as a “navigator” for calcium. It activates specific proteins that make sure calcium gets exactly where it is useful and is not deposited where it can do harm.

The main effects of vitamin K2 include:

Maintaining healthy bones and teeth

Vitamin K2 activates the protein osteocalcin, which helps incorporate calcium into bones and tooth enamel. Vitamin K2 therefore supports bone strength and density and helps reduce the risk of osteopenia or osteoporosis. [2] [3]

Protecting the heart and blood vessels

Vitamin K2 helps keep blood vessels healthy by activating (carboxylating) Matrix Gla Protein (MGP), which prevents calcium from depositing in the walls of blood vessels. Vitamin K2 therefore helps keep blood vessels flexible and, according to research, is associated with a lower risk of atherogenic plaque build-up and the development of atherosclerosis (hardening of the arteries). [1] [2]

Cardiovascular diseases, such as myocardial infarction, stroke and heart failure, are among the leading causes of death worldwide and in Europe. The main risk factors for heart disease include atherosclerosis and vascular calcification.

Supporting cell health and energy metabolism

Vitamin K2 also activates the Gas6 protein, which was discovered only in 1993 and can be found, for example, in the heart, lungs, stomach, kidneys and cartilage. [5] Gas6 is involved in the regulation of cell growth and division, promotes cell adhesion and helps protect cells (especially in the nervous system) from oxidative stress and premature cell death (apoptosis). It also contributes to protecting the mitochondria (the cells’ power plants). [4]

The effect on mitochondria is a subject of further research. In one study in which trained athletes and cyclists took vitamin K2 for 8 weeks, the authors observed support for mitochondrial function and energy production, which could be of interest especially for energy-intensive tissues such as skeletal and cardiac muscle. This is a preliminary finding that needs to be confirmed by further research.

Synergy with vitamin D3

Vitamin D3 increases the absorption of calcium from food into the blood, while vitamin K2 ensures its proper distribution from the blood into the bones. Taken together, they form an indispensable pair for overall health.

Vitamin K2 and statins

Statins are among the most commonly prescribed drugs for lowering LDL cholesterol levels, and their use has been on the rise in recent decades. It is widely known that statins deplete the body of coenzyme Q10, an antioxidant that helps create energy in the mitochondria, and patients taking statins are therefore advised to supplement coenzyme Q10. A 2015 study reports that statins can act as mitochondrial toxins and have a negative effect on the heart and vascular system, not only due to the depletion of coenzyme Q10 but also due to the inhibition of vitamin K2 synthesis, which protects blood vessels from calcification. [6] At present, however, there are no official recommendations for vitamin K2 supplementation in patients taking statins, and any supplementation should be discussed with a doctor.

Why is vitamin K2 missing from the modern diet?

Vitamin K1 is found in plant foods, especially green leafy vegetables, and getting enough of it from the diet is not a problem for most people. The situation with vitamin K2 is different. Part of our vitamin K2 is produced by our gut microbiome. In the past, a healthy microbiome could cover roughly half of the required production; today, with changes in lifestyle, eating habits and the microbial diversity of the population, it is estimated that our own production covers only about 10%.

Official recommendations do not make things any easier: they refer only to vitamin K1 in relation to blood clotting. EFSA considers an adequate daily intake of vitamin K1 to be 1 mcg per 1 kg of body weight. For vitamin K2 there is no separate intake recommendation. Given the limited amount the body makes itself, it is therefore necessary to ensure a regular intake from the diet or supplements.

Natural sources of vitamin K2 are very limited in the diet. The richest source is natto, a traditional Japanese dish made from fermented soybeans, which contains vitamin K2 in the biologically active MK-7 form. One 100 g serving of natto per week will cover the required dose of vitamin K2. Other sources are meat, dairy products and eggs from free-range animals (of grass-fed quality), which are hard to come by and contain the MK-4 form with a shorter half-life. Because few people regularly eat natto or grass-fed foods, it is assumed that the majority of the population suffers from a vitamin K2 deficiency.

How can I tell if I am deficient in vitamin K2?

Vitamin K2 deficiency may show up as more frequent bleeding (for example nosebleeds), a tendency to bruise, heavier menstrual bleeding in women or slower wound healing. A deficiency may not be noticeable at all for a long time, but its effects can appear over time as hidden weakening of bone tissue and damage to blood vessels.

How and when to take vitamin K2?

You can take vitamin K2 at any time of day, ideally for example in the morning with breakfast or at midday with lunch. The important thing is to build a regular daily habit.

For maximum absorption and effectiveness, it is good to follow these rules:

• With a meal containing fat: Because vitamin K2 is fat-soluble, the presence of fat is essential for its proper absorption in the digestive tract (a little is enough, e.g. a teaspoon of oil, an egg, yoghurt or nuts). D3+K2 drops in an oil base (organic MCT coconut oil) make absorption easier.

• Combine with vitamin D3: These two vitamins work synergistically. Supplementing vitamin D3 alone without enough K2 can lead to higher calcium levels in the blood without it being effectively deposited in the bones.

Which form of vitamin K2 to choose

When choosing a supplement, it is best to choose the MK-7 form obtained by natural fermentation (for example from chickpeas or natto) in the all-trans configuration, which guarantees the highest biological activity in the body.

All-trans vs. cis configuration: The terms all-trans and cis refer to a different molecular geometry (the size and shape of the molecule), which in turn determines the solubility and the ability of menaquinones to fit into cellular structures. The all-trans configuration is the biologically active form capable of activating K2-dependent proteins. By contrast, cis compounds have reduced activity or may be biologically inactive, because due to their altered shape they may not “fit” where they are supposed to.

Vitamin K2 at Trime comes exclusively from natural sources in the biologically active MK-7 form and in the all-trans configuration. Vitamin K2 in capsules is obtained by a patented bio-fermentation process from chickpeas, and you will find it both in the standalone Vitamin K2 supplement and in the Daily F20 Complex multivitamin. The D3+K2 drops and the children’s supplement Kids DHA+D3/K2 contain vitamin K2 obtained by natural fermentation of soy protein. We also refer to these supplements as “allergen free”, because they do not contain soy but the purified MK-7 molecule, and they are suitable for vegetarians and vegans.

Vitamin K2 - 120 µg

How much vitamin K2 per day?

The recommended daily dose of vitamin K2 depends on age, health status and the goals of supplementation:

• Preventive daily dose for adults from around 30 years of age: Usually in the range of 80 to 120 mcg of vitamin K2. You will find a dose of 120 mcg of vitamin K2 in the product Vitamin K2 capsules.

The Daily F20 multivitamin complex contains vitamin K2 in a daily dose of 75 mcg. This amount allows it to be combined with Vitamin D3+K2 drops, which contain 25 mcg of vitamin K2 for every 1000 IU of vitamin D3. Taking Daily F20 together with Vitamin D3+K2 drops is one of the most common combinations of our products, ensuring the necessary intake of essential nutrients while allowing you to personalise your vitamin D dose to your needs.

• Adults over 50, under higher strain or for therapeutic supplementation: In cases of increased risk of bone loss (for example with osteopenia or osteoporosis), or when taking higher doses of vitamin D3, doses of 150 to 200 mcg per day are recommended after consulting a professional.

Don’t forget vitamin K2 in summer

Because of its ability to regulate calcium deposition, vitamin K2 is often included in vitamin D supplements. During the winter months, many people therefore supplement K2 in blends together with vitamin D3. As the sunny days arrive and we raise our vitamin D levels naturally through sun exposure, consumption of D3K2 products decreases. The need for vitamin K2 remains, however, so we should not forget to supplement it in summer either. You can simply swap the D3K2 blend for a standalone vitamin K2 in capsules.

Vitamin K2 overdose

Vitamin K2 is generally considered very safe even at higher doses. There is no known toxicity associated with high doses of either vitamin K1 or vitamin K2. According to available expert recommendations, taking vitamin K2 in doses of up to 1000 micrograms (mcg) per day is considered safe for most healthy adults.

However, patients taking blood thinners from the group of vitamin K antagonists (for example warfarin) should be careful, as any increased vitamin K intake may reduce the effect of these medications. When taking anticoagulants, it is advisable to discuss vitamin K2 supplementation with your doctor.

Conclusion

Given the growing body of evidence on the importance of vitamin K2 for bone and cardiovascular health, it is time to rethink its role in our diet and health care. Its deficiency is common but overlooked, and yet it can have a major impact on quality of life. We therefore recommend paying attention to an adequate intake of vitamin K2, whether through quality foods (such as natto) or well-chosen supplementation in the biologically active MK-7 form.

Key takeaways

Sources and studies:

The well-known Rotterdam Study from 2004 found that a higher long-term intake of vitamin K2 (at a dose of at least 32 mcg per day) was associated with a lower risk of vascular calcification and cardiovascular disease. [1]

A 2015 clinical study in postmenopausal women observed improved arterial elasticity and reduced arterial stiffness after three years of daily vitamin K2 supplementation (180 mcg). [2]

[1] Geleijnse JM, Vermeer C, Grobbee DE, Schurgers LJ, Knapen MH, van der Meer IM, Hofman A, Witteman JC. Dietary intake of menaquinone is associated with a reduced risk of coronary heart disease: the Rotterdam Study. J Nutr. 2004 Nov;134(11):3100-5. doi: 10.1093/jn/134.11.3100. PMID: 15514282.

[2] Knapen MH, Braam LA, Drummen NE, Bekers O, Hoeks AP, Vermeer C. Menaquinone-7 supplementation improves arterial stiffness in healthy postmenopausal women. A double-blind randomised clinical trial. Thromb Haemost. 2015 May;113(5):1135-44. doi: 10.1160/TH14-08-0675. PMID: 25694037.

[3] Maresz K. Proper Calcium Use: Vitamin K2 as a Promoter of Bone and Cardiovascular Health. Integr Med (Encinitas). 2015 Feb;14(1):34-9. PMID: 26770129; PMCID: PMC4566462.

[4] Yan Q, Zhang T, O'Connor C, Barlow JW, Walsh J, Scalabrino G, Xu F, Sheridan H. The biological responses of vitamin K2: A comprehensive review. Food Sci Nutr. 2023 Jan 6;11(4):1634-1656. doi: 10.1002/fsn3.3213. PMID: 37051359; PMCID: PMC10084986.

[5] Ferland G. The vitamin K-dependent proteins: an update. Nutr Rev. 1998 Aug;56(8):223-30. doi: 10.1111/j.1753-4887.1998.tb01753.x. PMID: 9735675.

[6] Okuyama H, Langsjoen PH, Hamazaki T, Ogushi Y, Hama R, Kobayashi T, Uchino H. Statins stimulate atherosclerosis and heart failure: pharmacological mechanisms. Expert Rev Clin Pharmacol. 2015 Mar;8(2):189-99. doi: 10.1586/17512433.2015.1011125. PMID: 25655639.