Vitamin K2 Effect on Vascular Stiffening in Subjects With a Poor Vitamin K-status

Vitamin K is required for the activation of the inhibitor of vascular calcification: Matrix Gla Protein (MGP). In an earlier study the beneficial effect of menaquinone-7 (MK-7), a vitamin K2 form, was observed on the stiffness of the vessel wall in postmenopausal women. It decreased the circulating form of inactive MGP and improved the vascular elasticity (local) and aortic pulse wave velocity (regional). The decrease of circulating inactive MGP was observed after 2-3 months MK-7 supplementation and the effect of MK-7 on the clinical endpoints was observed within 3 years of supplementation. It is demonstrated in several studies that cardiovascular risk increases with decreasing vitamin K intake and increasing levels of inactive MGP. In this study the investigators select subjects in the highest tertile of circulating inactive MGP. This study group will consist of subjects with increased cardiovascular risk and it is expected that effects of MK-7 on clinical endpoints in this group will be measurable within 1 year of supplementation. Vascular stiffness can be determined with different techniques. The vascular characteristics determined with Pulse Wave Velocity (PWV), ultrasound of the common carotid artery and accelerated plethysmography (APG) with a fingertip device will be compared in a follow-up study.