Vitamin K - what is it?
Vitamin K, New RDA* 75 µg
Vitamin K is a fat-soluble vitamin. This means you don't need it every day because any of the vitamins your body doesn't need immediately is stored for future use.
Vitamin K1 is synthesised by plants. The vitamin K2 series is synthesised by various Gram-positive bacteria present in the jejunum and ileum.
*Sourced from EFSA WEBSITE
Vitamin K - what does it do?
Needed for the normal clotting of blood and is required for normal bone structure.
Vitamin K catalyses the carboxylation of a number of protein factors involved in blood clotting including prothrombin, forming the calcium binding sites on glutamyl side chains in the protein. Once carboxylated, the glutamates are referred to as gamma-carboxyglutamic acid (GLA). GLA-containing proteins are also found in the bone.For example, bone GLA protein (or osteocalcin) is thought to be involved in the limitation of bone growth, and matrix GLA protein may be involved in mobilisation and deposition of bone calcium. Kidney GLA proteins may be involved in reabsorption of calcium by the kidney tubules and solubilisation of calcium salts in urine. GLA-containing proteins have also been found in the placenta, pancreas, spleen and lungs, but the majority of these have not yet been characterised. Vitamin K-dependent proteins are also thought to have roles in cell signalling and brain lipid metabolism.
Deficiency
Vitamin K is widely available from the diet and is also provided by gut bacteria. Thus, deficiency is generally secondary to conditions such as malabsorption or impaired gut synthesis. Hospitalised patients can be at risk of vitamin K deficiency following the use of antibiotics or gastrointestinal surgery. Newborn babies have low levels of vitamin K, which may result in haemorrhagic disease of the newborn.
