Effect of vitamin K producing probiotics on vitamin K status in human

At the time of its discovery, in 1929, vitamin K was mainly considered a coagulation cofactor, but in recent decades it has become clear that vitamin K deficiency plays an important role in the development of cardiovascular disease and osteoporosis. The prevalence of vitamin K deficiency has increased in western society, and is seen especially in the elderly and in certain patient groups such as patients with type 2 diabetes and kidney disease.  

Vitamin K is a fat-soluble vitamin present in our diet in two forms, namely as phylloquinone (vitamin K1) in green leafy vegetables and as menaquinone (vitamin K2) in fermented foods such as cheese, yoghurt and buttermilk. Besides various dietary sources, vitamin K2 is also produced by gut bacteria. It was recently discovered that certain probiotic strains, already on the market, are capable of producing vitamin K2 in vitro. In the PROVITAK project, probiotic formulation containing these vitamin K2-producing bacteria were administered  in adults aged 50-75 years with an increased risk of cardiovascular disease to investigate whether vitamin K status could improve in these individuals. Specifically,  probiotics or placebo were supplemented for 12 weeks and menaquinones were measured before and after administration in faeces and blood. Results show an significant increase of vitamin K levels in the human body after 12 weeks of supplementation which indicates the ability of the specific probiotics to elevate the vitamin K status in humans.