An abundance of human clinical data reveals that vitamin K plays a critical role in maintaining healthy bone density by facilitating the transport of calcium from the bloodstream into the bone.6-10 Vitamin K is also required by calcium-regulating proteins in the arteries. Matrix Gla-protein (MGP) is a vitamin K-dependent protein, and it must be carboxylated to function properly. Poor vitamin K status leads to inactive uncarboxylated MGP (ucMGP), which accumulates at sites of arterial calcification.11,12 Since MGP is a potent local inhibitor of arterial calcification, MGP is important in relation to the health of the entire cardiovascular system. Without adequate vitamin K, calcium in the blood can bind to the arterial wall resulting in calcification.13,14 As people age, even a subclinical vitamin K deficiency can pose risks to the vascular system. Poor vitamin K status also results in increased circulating levels of undercarboxylated osteocalcin that is shown to be associated with increased bone loss in postmenopausal women.15,16
Vitamin K2 (menaquinones) is found in meat, eggs, and dairy products and is also made by bacteria in the human gut, which provides a certain amount of the human vitamin K requirement.20 Human studies show that vitamin K2 is up to ten times more bioavailable than K1. Vitamin K2 remains biologically active in the body far longer than K1. For instance, K1 is rapidly cleared by the liver within eight hours, whereas measurable levels of K2 (MK-7) have been detected 72 hours after ingestion.10
The Rotterdam Heart Study, a large-scale, well-controlled clinical trial that tracked 4,800 participants for seven years, revealed that participants who ingested the greatest quantities of vitamin K2 in their diet experienced a better cardiovascular condition than people who ingested the least.21 High intakes of vitamin K2 also corresponded to less calcium deposition in the aorta, whereas participants who ingested less K2 were more likely to show moderate or severe calcification. Animal studies suggest vitamin K intake not only blocks the progress of further calcium accumulation, but also induces 37% regression of preformed arterial calcification.22,23
Low-Dose Vitamin K2 contains the menaquinone-7 form of vitamin K2, which is not metabolized quickly by the liver, thereby making it available to provide a more consistent supply of vitamin K to the body.