Vitamin K for the primary prevention of cardiovascular disease.
What this study found
Vitamin K2 (MK-7) did not show meaningful effects on blood pressure or lipid levels over 12 weeks, and no clinical cardiovascular outcomes were reported. In the 180 µg/day arm, the mean difference versus placebo was -6.75 for systolic blood pressure, 0.0 for diastolic blood pressure, 0.20 for total cholesterol, 0.0 for LDL-C, 0.0 for HDL-C, and 0.1 for triglycerides. In the 360 µg/day arm, the corresponding mean differences were 1.74, 2.32, -0.10, 0.20, 0.0, and 0.1. The evidence base is extremely limited, so no firm conclusion can be drawn about vitamin K for primary prevention of…
- Study & population
- Systematic review of randomized trial evidence for primary prevention of cardiovascular disease, with one included study in apparently healthy adults from the Netherlands.
- Intervention
- Vitamin K2 as menaquinone-7 (MK-7) was given orally for 12 weeks in two active regimens: 180 µg/day as one MK-7 capsule plus one placebo capsule daily, or 360 µg/day as two MK-7 capsules daily.
- Key limitation
- Evidence came from only one small randomized trial with short 12-week follow-up, so clinical cardiovascular prevention cannot be assessed.
View source
Open PDFOriginal abstract
BACKGROUND A deficiency in vitamin K has been associated with increased calcium deposition and coronary artery calcification, which may lead to cardiovascular disease. OBJECTIVES To determine the effectiveness of vitamin K supplementation as a single nutrient supplement for the primary prevention of cardiovascular disease. SEARCH METHODS We searched the following electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 8 of 12, 2014); MEDLINE (Ovid, 1946 to September week 2 2014); EMBASE Classic + EMBASE (Ovid, 1947 to September 18 2014); Science Citation Index Expanded (SCI-EXPANDED) and Conference Proceedings Citation Index, Science (CPCI-S) (both 1990 to 17 September 2014) on Web of Science (Thomson Reuters); Database of Abstracts of Reviews of Effects (DARE); Health Technology Assessment Database and Health Economics Evaluations Database (Issue 3 of 4, 2014). We searched trial registers and reference lists of reviews for further studies. We applied no language restrictions. SELECTION CRITERIA We included randomised controlled trials of vitamin K supplementation as a single nutrient supplement, lasting at least three months, and involving healthy adults or adults at high risk of cardiovascular disease. The comparison group was no intervention or placebo. The outcomes of interest were cardiovascular disease clinical events and cardiovascular disease risk factors. DATA COLLECTION AND ANALYSIS Two review authors independently selected trials for inclusion, abstracted the data and assessed the risk of bias. MAIN RESULTS We included only one small trial (60 participants randomised) which overall was judged to be at low risk of bias. The study examined two doses of menaquinone (vitamin K2) over 3 months in healthy participants aged 40 to 65 years. The primary focus of the trial was to examine the effects of menaquinone (subtype MK7) on different matrix Gla proteins (MGP - vitamin K dependent proteins in the vessel wall) at different doses, but the authors also reported blood pressure and lipid levels. The trial did not report on our primary outcomes (cardiovascular disease clinical events) as it was small, short term and conducted in healthy participants.In terms of cardiovascular disease risk factors, no effects were seen for vitamin K2 on blood pressure or lipid levels, although the trial was small and findings are limited. The trial did not report any of our other secondary outcomes. AUTHORS' CONCLUSIONS The very limited results of this review highlight the lack of evidence currently available to determine the effectiveness of vitamin K supplementation for the primary prevention of cardiovascular disease, and demonstrate the need for further high quality trials in this area.