Vitamin K
Optimal dose 50-500 mcg/day
Vitamin K is also needed (along with magnesium and vitamin D) to build strong bones. Vitamin K (as K2) has been shown to decrease the risk of heart disease, and in men helps enhance insulin sensitivity. For the “science-minded” reader, the information below adds some background.
Vitamin K and Heart Disease
Professors Cees Vermeer and Leon Schurgers, of VitaK, at Maastricht University, the Netherlands, a leading research institute specializing in the role of vitamin K in the field of bone and cardiovascular health, provided the statement “There are two vitamins known to be involved in calcium metabolism: vitamin D and vitamin K. Increased calcium intake, especially if combined with vitamin D, results in increased absorption of calcium.”
“However, vitamin K is required for activation of the vascular protein MGP, which is an inhibitor of calcification. In fact it is the strongest inhibitor of tissue calcification presently known and it is the only calcification inhibitor found in the vasculature. Using highly specific assays, the VitaK research group at the Maastricht University has demonstrated that the vitamin K intake by non-supplemented adults (almost without exception) is insufficient to completely activate MGP (at best 70% is activated). This means that healthy adults are not optimally protected against vascular calcification, even in the absence of an extra calcium load. Subjects of 50 years and older even have a still lower vitamin K status, and hence a higher fraction of their MGP is synthesized in an inactive form.”
“When knowing these facts, it is only to be expected that an increased calcium intake will lead to increased artery calcification. This is what may happen if incomplete supplements are provided. It has been demonstrated in large population-based studies, in experimental animal studies and in cell culture studies that the efficacy of vitamin K2 in vascular calcification protection is far better than that of vitamin K1.”
“However, at high intakes even K1 was shown to maintain vascular elasticity in a three-year study. Although a large clinical intervention trial on the cardio-protective effect of K2 at high calcium intakes has not yet been published, all data presently available suggest that supplements containing calcium and vitamin D without K2 are incomplete, and may have unexpected adverse side effect in the cardiovascular area.”
A 2004 study published in the Journal of Nutrition, called the “Rotterdam Study,” followed over 4,800 people for a ten year period. The study found increased intake of specifically vitamin K2 from dietary sources significantly reduced the risk of CHD mortality by 50% as compared to low dietary vitamin K2 intake.
More Information Online
Nutritional primer
We have a 20,000 word primer on nutrition at our website that provides more detail with study references on each nutrient. Click here to visit the "Vitamin K" section of our primer.