Are We Keeping Our Patients Fat Soluble Vitamins Balanced: What about vitamin K????

Bacteria that normally colonize the large intestine synthesize menaquinones (vitamin K2), which are an active form of vitamin K. Until recently it was thought that up to 50% of the human vitamin K requirement might be met by bacterial synthesis. However, research indicates that the contribution of bacterial synthesis is much less than previously thought, although the exact contribution remains unclear. (from Linus Pauling Institute)

Suttie JW. The importance of menaquinones in human nutrition. Annu Rev Nutr. 1995;15:399-417