2023-04-26 08:39:00
K1, K2: What are the two forms of vitamin K?
Vitamin K belongs to the group of fat soluble vitamins – in the same way as vitamins A, D and E – which means that they are fat solubleunlike water-soluble vitamins, which are soluble in water.
Vitamin K exists in two forms in food:
– The K1 shape : also called phytomenadione, phylloquinone or phytonadione. “We find this form mainly in foods of plant origin” explains Raphaël Gruman,
– The K2 form: or menaquinone, found in foods of animal originbut which can also be synthesized by the bacteria of our intestinal flora – says microbiota.
There is also a third form of vitamin K, called vitamin K3 or menadionewho is syntheticand is therefore not natural.
How much vitamin K2 do we need per day?
Vitamin and mineral requirements are established in France by the French Food Safety Agency (ANSES). Regarding vitamin K, we speak of satisfactory intakes (AI) defined as the average intake of a population or a subgroup for which the nutritional status is considered satisfactory.
In adults (over 18 years old), both men and women, these AIs are set at 79 μg/d, which must be provided either in the form of vitamin K1 or K2.
A a varied diet normally allows you to meet your needs quite easily vitamin K. According to ANSES, “cases of dietary vitamin K deficiency are rare but can induce lipid absorption disorders”.
Role and benefits: what is vitamin K2 or menaquinone used for?
Mineral density, osteoporosis and osteoarthritis
“Vitamin K2 plays a major role in bone calcification” indicates Raphaël Gruman. She acts in boosting the activation of osteoblasts which produce a molecule called osteocalcin. This molecule acts as capturing calcium from the bloodstream in order to bind it to the bone matrix.
Several studies thus highlight the fact that, through this phenomenon, vitamin K – and by extension vitamin K2 – would be able to improve bone mineral density in people suffering from osteoporosis, and consequently reduce the risk of fractures (1 and 2).
According to these studies, high doses (up to 45 mg/day) of vitamin K2 may improve bone health et reduce the risk of fracture fractures (by 77%), vertebral fractures (by 60%) and all non-vertebral fractures (81%).
By the same token, vitamin K2 could reduce the risk of osteoarthritisjoint disease that leads to the destruction of cartilage.
Hypertension and Cardiovascular Diseases
By participating in the synthesis of osteocalcin, vitamin K2 would help to decalcify the soft tissues of the arteries, likely to calcify over time. By this process, this vitamin would limit the occurrence of several cardiovascular pathologiessuch as infarction, arterial hypertension or heart failure.
When it is associated with vitamin D, and in particular vitamin D3, menaquinone would act by improving the elasticity of the arterial walls.
Cancers
According to a Spanish study from 2014 (3), a increased doses of vitamins K1 and K2 would be associated with a reduced risk of death from cancer, all causes combined. It would seem that vitamin K would be able to inhibit the cell growth of cancerous cells.
Foods: where to find natural vitamin k2?
“Vitamin K2 comes only from foods of animal originunlike vitamin K1 from the plant kingdom” recalls the dietician. It is also a fat-soluble vitamin, which is therefore logically found in greater quantities in foods rich in fats.
The main sources of K2 are: liver (veal, beef, pork, monkfish…), fatty dairy products, fatty meats and fish, egg yolk and fish oils.
Which cheeses are the richest in vitamin K2?
The vitamin K2 (or menaquinone) content of cheeses varies mainly according to its fat content and its ripening period: the fatter and longer a cheese is, the richer it will be in vitamin K2.
The cheeses that are best provided with it are: Gouda, Edam, Raclette cheese, Munster, Camembert and Vacherin.
The poorest are Gruyère, alpine cheese and Italian cheeses, including parmesan.
Side effects: Should vitamin K2 be limited in case of anticoagulant treatment?
Vitamin K, whether it is the form of vitamin K1 or K2, intervenes in blood clotting. When it is not sufficiently provided by the diet, therefore in the event of vitamin K deficiency, the liver releases non-functional coagulation factors called PIVKA: Proteins Induced by the Absence of Vitamin K. This is what phenomenon which is at the origin of the pharmacological effect of anticoagulant drugs known as “anti-vitamin K”.
Raphaël Gruman dietitian nutritionist: Patients treated with AVK-type anti-coagulants must greatly limit their consumption of vitamin K, at the risk of interfering with the treatment.
The foods richest in vitamin K (K1 and K2) must therefore be reduced for patients undergoing AVK treatment, to a maximum of one portion per day of the foods that are the richest, all combined. It is moreover formally contraindicated to undertake vitamin K2 supplementation when one is under AVK treatment.
At recommended doses, and even in the form of dietary supplements, the side effects of vitamin K2 are extremely rare. “However, an overdose can in rare cases cause potentially serious symptoms: loss of appetite, yellowing of the skin and eyes (jaundice), difficulty in breathing, swelling of the body, muscle stiffness…” indicates the dietitian. It is then essential to consult immediately.
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