Vitamin K may be useful in preventing arteriosclerosis. Arteriosclerosis refers to the stiffening or hardening of the arterial walls. Atherosclerosis is a specific type of arteriosclerosis in which arteries narrow due to plaque buildup. One of the key features of arteriosclerosis is the accumulation of calcium within the arterial walls.
Matrix Gla-protein (MGP) plays an important role in inhibiting arterial calcification, and this protein requires vitamin K in order to function properly. The anticoagulant drug warfarin interferes with MGP activity. As a result, warfarin use can promote arterial calcification.
An animal study published in Blood (April 1, 2007; Vol. 109, No. 7, pp. 2823–2831) examined whether vitamin K supplementation could reverse warfarin-induced arterial calcification. In this study, arterial calcification was induced in rats by administering warfarin over a six-week period. The rats were then divided into four groups and treated for an additional six weeks with one of the following: continued warfarin alone, a low dose of vitamin K (5 mcg per gram of food), a high dose of vitamin K1 (100 mcg per gram of food), or a high dose of vitamin K2 (100 mcg per gram of food).
Arterial calcification continued to progress in the rats receiving warfarin alone or warfarin combined with the low dose of vitamin K. In contrast, rats receiving high doses of either vitamin K1 or vitamin K2 experienced significant reductions—up to 50 percent—in arterial calcification. High-dose vitamin K supplementation also improved arterial flexibility.
The researchers found evidence of localized vitamin K deficiency in areas where arterial calcification was present. The findings suggest that arterial calcification and reduced arterial distensibility may be reversible with high-dose vitamin K supplementation.
