Vitamin K is a fat-soluble vitamin that comes in two forms: vitamin K1 (phylloquinone) is found in plants; and vitamin K2 (menaquinone) is found in meat, egg yolks and dairy products. Vitamin K2 is most abundant in natto, a Japanese food made from fermented soybeans, where it is found in its most bioavailable form, menaquinone-7. Vitamin K is also synthesised by the microflora of the small intestine in the body, but it has been found that the forms of vitamin K obtained from food are absorbed more rapidly by the body. Vitamin K does not accumulate in the body; only a small amount is found in the liver and bones, which is sufficient to meet the body’s needs for several days. A vitamin K deficiency can occur as a result of the impaired synthesis and absorption of vitamin K (especially as a result of the prolonged use of antibiotics or anticoagulants), or as a result of an inadequate diet, which is why taking vitamin K supplements may be a good option.
Vitamin K is important for both mineralisation and blood clotting.
- Vitamin K supports normal blood clotting by being involved in the biosynthesis of many blood clotting factors (the enzymes involved in blood clotting).
- Vitamin K is known to be involved in the synthesis and activation of the matrix Gla protein (MGP), which is secreted by the vascular smooth muscle cells and is involved in the regulation of the deposition of calcium in the blood vessel walls.
- Vitamin K has been proven to help maintain normal bone health, as it is essential for the formation and maintenance of a normal bone structure. This vitamin is involved in the activation of osteocalcin, a calcium-binding protein secreted by osteoblasts, to stimulate the mineralisation process in the bones. If osteocalcin is not properly activated, it does not bind calcium and an excess of this mineral remains in the blood.
