In today’s post, Dr. Hernán Sosa will address a topic of growing interest both for the preservation of health and for the prevention of diseases: vitamin K.

When we usually talk about vitamins, the first ones that usually come to mind are the best known, C in first place -surely-, then those of group B -of whom we have talked at length in this blog- and perhaps followed by vitamin D, which had such a boom during the last pandemic.

But there is a group of vitamins with properties that are not so well spread and therefore not so well known but that mean a lot to our health.
Today we will talk more broadly about this topic and we will point out the main differences that will surely help you see the importance of this vitamin.

How many types of Vitamin K are there?

Although we commonly name vitamin K as a single one, chemically there are two possible natural forms, vitamin K1 or phylloquinone and vitamin K2 which belongs to the menoquinone (MK) family.
In turn, there are other synthetic forms that are not the subject of this article.

Although this fat-soluble vitamin is essential for the body, its necessary amounts are quite low compared to other cofactors.
The adequate intake level of vitamin K is set at 90μg/day for women and 120μg/day for men.

What are the main sources?

In general, we can say that vitamin K1 is found in green leafy vegetables and some vegetable oils (soy, canola and olive) and represents approximately 90% of the daily intake.
However, the phylloquinone bioavailability of vegetables is lower than that of oil and supplements.
As an additional fact, we can say that the phylloquinone content of green leafy vegetables depends on their chlorophyll content, so the leaves of a more intense green would have more phylloquinone than the paler ones.

Oil and vitamin K supplements are better absorbed than plant products

Menoquinones, or vitamin K2, are found primarily in animal foods, such as meat, dairy, and eggs.
Another part has microbial origin and is therefore commonly found in fermented foods, such as cheese, yogurt, and natto, which is a product of Japanese origin made from soybeans fermented with bacillus subtilis.

https://lpi.oregonstate.edu/mic/vitamins/vitamin-K

Something quite important:

With regard to meat of animal origin, we have to make a caveat.
Since vitamin K2 is a byproduct of K1 and animals should consume vitamin K1 from green pastures to produce vitamin K2, this is not currently the case in the vast majority of livestock.
In these times, cattle are fed with industrial feed derived mostly from cereals.
This means that the levels that should be found in foods of this origin may not contain adequate amounts.

Why Vitamin K?

Vitamin K was identified by the Danish physician Henrik Dam, who together with the American physician Edward Doisy, discovered its physiological effects and earned them a Nobel Prize in 1943.
The discovery of this new fat-soluble vitamin, which had an extremely important role in the coagulation cascade, received the letter K because the initial discoveries were reported in a German journal, in which it was designated as the Koagulations (coagulation vitamin in German).

What are the functions of Vitamin K1?

The word that should stick in our minds regarding vitamin K1 is coagulation.
This vitamin functions as a cofactor for the enzyme γ-glutamylcarboxylase (GGCX), which catalyzes the carboxylation of glutamic acid (Glu) to γ-carboxyglutamic acid (Gla).
Vitamin K-dependent γ-carboxylation that occurs only at specific glutamic acid residues in identified vitamin K-dependent proteins (VKDPs), is critical in its ability to bind to calcium in negatively charged areas of the phospholipid membrane and thus maintains hemostasis.

https://doi.org/10.1155/2017/6254836

Another very important issue to keep in mind is that some oral anticoagulants, such as warfarin, inhibit clotting by antagonizing the action of vitamin K.
La warfarina previene el reciclaje de la vitamina K al bloquear la actividad de VKOR, creando así una deficiencia funcional de vitamina K.

Vitamin K1 is coagulant

Some observational studies have found a link between phylloquinone (vitamin K1) and age-related bone loss.
The Nurses Health Study followed more than 72,000 women for 10 years.
In an analysis of this cohort, women whose phylloquinone intakes were less than 109μg/day had a 30% higher risk of hip fracture compared to women with intakes equal to or greater than 109μg/day.
DOI: 10.1093/ajcn/69.1.74

Another prospective study in more than 800 elderly men and women, which grew out of the Framingham Heart Study, found that participants with dietary vitamin K intakes in the highest quartile (median of 254μg/day) had a 65% lower risk of hip fracture than those with intakes in the lowest quartile (median of 56μg/day).
DOI: 10.1093/ajcn/71.5.1201

The Next Great Vitamin: K2

There are many studies that already provide a broad spectrum with reference to vitamin K2.
Apparently, this small fraction that depends on vitamin K1 would intervene in numerous processes related to cardiovascular health, immunity and neurodegenerative diseases.

• Cardiovascular health: Vitamin K2, in the form of MK-7, has a long-term protective effect on the development of arterial calcification. https://doi.org/10.3390/nu10040415

In addition, several studies have shown an overall reduction in the risk of developing coronary heart disease.
A regression of arterial stiffness and an improvement in vascular elasticity have even been observed in healthy population cohorts after supplementation. https://doi.org/10.1016/j.numecd.2008.10.004

• Immune system: MK-7 was shown to modulate the expression of TNF-α, IL-1α, and IL-1β.
  In addition to this finding, vitamin K2 would decrease the proliferation of T cells in healthy individuals. https://doi.org/10.1111/odi.12759

• Neurodegenerative diseases: A protective effect of vitamin K2 on neurons in vitro has been documented.
  In addition, MK-4 improved energy production and rescued the PINK1 mutation found in Parkinson’s disease. https://doi.org/10.1080/1028415X.2018.1504428

More recently, research identified the protection of neurons with vitamin K2 through a novel mechanism involving the P38 kinase pathway MAP.
DOI: 10.1126/science.1218632

Some frequently asked questions

Taking into account some common doubts of our users, the following questions should be asked:

1. If a patient takes blood thinners, should they avoid taking vitamin K1?

Exactly, anticoagulated patients should avoid consuming both foods high in vitamin K1 and supplements that contain it.
Recall that one of the main functions of vitamin K1 is to activate steps in the coagulation cascade, therefore the most commonly used anticoagulants (hydroxycoumarin derivatives including warfarin and acenocoumarol) specifically inhibit VKOR, thus preventing the recycling of vitamin K.
High concentrations of vitamin E also act by enhancing anticoagulation.

2. In the case of the same patient, could he take vitamin K2?

Yes, it can and in fact it is beneficial.
In a study derived from the famous Rotterdam Study, MK-4 (vitamin K2) supplementation, prevented warfarin-induced arterial calcification, DOI: 10.1159/000075344

3. If we want to reduce fractures, what form of Vitamin K should we take?
   In this case, studies show that there is a clear relationship between vitamin K1 intake and a lower incidence of hip fractures.
   This is explained by the apolipoprotein E (APOE) gene, which has 3 alleles: E2, E3 and E4.

The E4 allele was associated with an increased risk of several diseases and an increased risk of fracture in several populations.
One explanation for the increased risk of fractures is that APOE is involved in the transport of vitamin K in the blood and that less vitamin K is available in E4 allele carriers.
Vitamin K is needed to carboxylate osteocalcin.
Concentrations of infracarboxylated osteocalcin were associated with an increased risk of hip fracture, and lower concentrations of circulating vitamin K were found in women with osteoporotic fractures.
Short-term vitamin K supplementation corrected osteocalcin undercarboxylation in women with Colles fractures.
DOI: 10.1016/8756-3282(96)00037-3

Conclusion

The discovery of different isoforms of vitamin K is beginning to elucidate that its health benefits extend beyond blood clotting and are implicated in chronic inflammatory diseases such as cardiovascular diseases, osteoarthritis and others related to cognitive decline.

In addition, there is a growing body of evidence suggesting that vitamin K2 may be involved in multiple cellular processes and may have a protective function in various organs throughout the human body.

That is why at Salengei we have developed a new product for immunity that will contain vitamin K2 in the form of menaquinone 7 (MK-7) and whose name is Active Omega-3 Immunity.

We are sure that Active Omega-3 Immunity will bring more than health benefits in both the medium and long term.

We thank you again for the time you spend reading each of our articles and the comments and suggestions that you send us to our email.
At Salengei we are dedicated to the research and development of products focused on the health and well-being of each one of you.
See you in the next installment!