Vitamins K – a group of chemical compounds derived from 2-methyl-1,4-naphthoquinone. The human body needs about 125 μg of vitamin K daily. In the body it undergoes the regeneration process in the liver in the vitamin K cycle. It can also be produced by bacteria found in the large intestine.
K vitamins are two natural (fat-soluble):
• vitamin K1 (fitomenadion, fitonation, phylloquinone and others), which in the third position has a phytyl residue.
• vitamin K2 (menachinone-6, farnochinone), which in the third position has a difarnesyl residue or other isoprene groups.
The main role of vitamin K is to participate in the post-translational γ-carboxylation processes of PIVKA proteins, and more specifically the glutamic acid residues in these proteins in the γ position. Vitamin K participates in this reaction as a co-factor of γ-carboxylase. This conditions:
• maintaining the correct concentration of coagulation factors: II, VII, IX, X, as well as: osteocalcin, osteopontin, osteonectin.
• proteins that inhibit blood clotting: protein C, protein S
• calcium-binding proteins in the kidneys, placenta and lungs.
In addition, these vitamins are involved in glycosylation processes.
The functions of vitamins K in the body
• regulate prothrombin production
• affect blood coagulation
• play a role in the calcium economy
The effects of scarcity
Deficiency of K vitamins causes:
• poor blood clotting,
• ease of internal and external bleeding,
• problems with wound healing,
• poor bone mineralization,
• increased risk of cancer, inflammation of the intestine, diarrhea.
Vitamin K deficiency is the cause of VKDB, which is prevented by the administration of vitamin K. Clinical data indicate that a single intramuscular injection immediately after birth is much more effective than multi-day oral administration.
The effects of excess
An excess of vitamin K can cause:
• breakdown of red blood cells,
• excessive secretion of sweat,
• feeling hot,
• in infants – jaundice and brain tissue damage.
Products containing vitamin K
Vitamin K can be produced by the saprophytic intestinal flora; they are also found in many food products, such as broccoli, celery, turnip, spinach, cucumber, dandelion, lettuce, cabbage, alfalfa, and avellado, also in potatoes, eggs, yoghurt, cheese, liver, soy and safflower oil.