Vitamin K and its role
> The Vitamins they are organic nutrients, having a relatively simple chemical structure that are not digested after intake, but on the contrary are found inside macromolecules as cofactors.
Their function is very varied as they mainly act as biocatalysts in numerous metabolic processes essential to the body.
They are usually divided into two large families:
- water-soluble vitamins (group B, vitamin C)
- and liposoluble vitamins (A, D, E, DK).
In particular, vitamin K, also called antihemorrhagic, is a set of structurally and functionally related fat-soluble compounds (vitamin K1, or phylloquinone, vitamin K2 and vitamin K3, or menadione), essential for the hepatic synthesis of prothrombin and other coagulation factors.
Vitamin K is absorbed in the intestine and stored in the liver.
On a physiological level, its action takes place by forming an integral part of a carboxylase enzyme that it plays a vital role on the main proteins involved in the coagulation process including: prothrombin, proteins C, S and Z which are made biologically active.
Coagulation: between physiology and pathology
Blood clotting is a relevant process which prevents excessive bleeding when a blood vessel is injured. Platelets and proteins.
Generally, the body is able to naturally dissolve the blood clot after the wound has healed but situations (thrombosis and / or bleeding) may occur that require accurate diagnosis and appropriate treatment.
In any case, physiologically, coagulation is a highly controlled process and monitored that must follow a predetermined path: the initial trigger is the endothelial damage that causes the release, by the cells of the tissue itself, of some factors called endothelin, strong vasoconstrictors that act in the arterioles at the level of the lesion, in in such a way as to hinder any blood loss.
Vasoconstriction reached in this way, assisted by a further vasoconstriction of nervous origin, it is however only temporary. In fact, it will be only during primary and secondary haemostasis that the actual clot will form, through a cascade of signals and events with the involvement of many coagulation factors (numbered from I to XIII).
As previously mentioned, however, all this can have negative implications, in the context of some important pathologies affecting the cardiovascular system.
In the case of thrombosisin fact, the formation of a possible clot must necessarily be countered by taking anticoagulant or blood thinning drugs that will make it difficult for the body to produce clotting factors or prevent the functioning of proteins in the clot formation process.
In the case of hemorrhagic pathologiesthe opposite effect occurs on platelets, capillaries or the entire process (for example haemophilia): excessive and, at times, uncontrollable blood loss due to defects located at various levels of the coagulation cascade .
Nutrition and vitamin K in coagulation
Vitamin K brings important benefits to our body and it is essential for those with blood clotting problems, as it supplies the liver with the substances necessary to produce clotting factors.
The limit of this vitamin is, however, its absorption which turns out to be only 10% of the requirement deriving from food and nutrition in general. Integrating it, therefore, with a balanced diet is essential.
But, on a food level, where is it possible to find it? Le best sources of vitamin K are represented by:
> dried legumes (chickpeas 264 mcg / 100g, lentils 123 cmg / 100g);
> brassicas (cauliflower 300 mcg / 100g);
> Brussels sprouts (236 mcg / 100g);
> other green leafy vegetables: spinach (305 mcg / 100g,) lettuce (109 mcg / 100g).
Less relevant quantities are found instead in: cereals, legumes, meat, fish, eggs, dairy products.
Beyond food sources, the main source of vitamin K, in physiological health conditions, should come from our intestine: the eubiotic intestinal flora (or microbiota) in fact produces a non-negligible amount, although not exactly known, which is reabsorbed in the colon.
Aside from reduced food intake, the most frequent causes of deficiency of this vitamin are to be sought following organic or functional pathologies that lead to reduced intestinal absorption:
> intestinal dysbiosis;
> inflammatory bowel diseases;
> celiac disease;
> primary and secondary food intolerances;
> pathologies affecting the liver, gallbladder (hepatitis, liver cirrhosis, gallbladder stones) and pancreas (pancreatitis).
From the pathological point of view it appears evident how the Vitamin K administration is a lifesaver to prevent bleeding problems in infants with low vitamin K levels or to treat and prevent bleeding problems in adults with low prothrombin levels.
Vitamin K and anticoagulant drugs
When food and drugs are taken orally there is concrete possibility that interactions occur at the level of the digestive system, also very dangerous.
Certain foods are in fact capable of altering the absorption and metabolism of certain drugs such as anticoagulant therapies.
Since the dose of anticoagulants required varies widely between individuals, it is essential to measure the clotting time through a specific blood test, the "prothrombin time", which measures the time it takes the clot to form when the blood is put in contact with specific substances.
The answer is expressed as Prothrombin activity or preferably like IN R: the higher the INR the greater the fluidity of the blood.
The action of oral anticoagulant drugs is based on interference with vitamin K present in different types of food and given that some foods contain high amounts of vitamin K, excessive intake of the same could cause an increase in vitamin K concentration in the blood and therefore a decrease in INR by increasing blood density due to activation of clotting factors, thus increasing the risk of thrombosis.
However, these foods must not be excluded from the diet, their intake must be moderate and regular over time, thus standardizing the intake of vitamin K as much as possible.
On the other hand, a diet that completely excludes these foods could lead to a vitamin K deficiency with consequent risk of bleeding. There are therefore no reasons to abolish or reduce the intake of vegetables and fruit: these foods do not alter the response to therapy, while they are able to help us not gain weight and regulate the intestine.
Vitamin K and practical advice
Here are some foods they do lower the INR because they are rich in vitamin K (denser blood) and which must be taken with more control.
Bevande: alcohol, caffeine, ginger, green tea, cranberry and grapefruit juice, decaffeinated tea, oat milk, soy milk, pear juice .. They interfere with the hepatic metabolization of anticoagulants and when taken, the elimination of oral anticoagulants is slowed down, increasing their effect.
Legumes: Soy
Cereals: CousCous, Avena
Meat: Liver
Vegetables: Broccoli, Cauliflower, Brussels sprouts, Turnip greens, Onion, Sauerkraut, Salad leaves, Bamboo sprouts, Bean sprouts, Endive, Mixed salad, Lettuce, Canned corn, Leeks, Red and green radicchio, Turnip, Rocket Celery, Spinach, Valerian, Cabbage and Pumpkin. Furthermore, cooking tomato and fennel significantly reduces their vitamin K content.
Dried Fruit: Pine nuts.
