High blood pressure is a widespread health concern. Dietary approaches to support cardiovascular well-being have gained interest, with Vitamin K2 emerging as a subject of exploration. This article examines the current understanding of Vitamin K2 and its possible influence on blood pressure.
Understanding Vitamin K2
Vitamin K is a group of fat-soluble nutrients, broadly categorized into Vitamin K1 (phylloquinone) and Vitamin K2 (menaquinone). While Vitamin K1 is primarily found in leafy green vegetables and is known for its role in blood clotting, Vitamin K2 is distinct in its biological activities and sources. It plays a role in calcium metabolism, guiding calcium towards bones and away from soft tissues. This function contributes to bone health and overall cardiovascular well-being.
Vitamin K2 encompasses several subtypes, referred to as menaquinones (MKs), which are numbered based on the length of their side chains, such as MK-4 and MK-7. MK-4 is found in certain animal products like egg yolks, liver, and some meats. Longer-chain menaquinones, particularly MK-7, are more prevalent in fermented foods such as natto, a traditional Japanese fermented soybean dish, and certain cheeses like Gouda and blue cheese.
Vitamin K2’s Influence on Blood Pressure
Vitamin K2 impacts blood pressure through its involvement in regulating calcium within the body. It helps direct calcium to appropriate locations, such as bone tissue, rather than allowing it to accumulate in arterial walls. Calcium deposits in arteries can contribute to their hardening and reduced flexibility, which can in turn affect blood pressure.
A key mechanism involves the activation of Matrix Gla Protein (MGP), a protein present in arterial walls. MGP requires Vitamin K2 to become biologically active and function as an inhibitor of arterial calcification. By activating MGP, Vitamin K2 helps prevent the buildup of calcium in arteries, thereby supporting the maintenance of arterial elasticity. This preservation of arterial flexibility is a factor in maintaining healthy blood pressure levels and reducing the strain on the heart.
Research Findings and Practical Considerations
Current scientific evidence suggests a link between Vitamin K2 and cardiovascular health, including arterial stiffness and blood pressure. Observational studies indicate that higher dietary intake of Vitamin K2 is associated with a reduced risk of coronary heart disease and arterial stiffening. Intervention trials have also explored these effects, with some showing positive outcomes.
For example, a 2020 study found that daily supplementation with 180 mcg of MK-7 improved vascular flexibility and blood pressure, particularly in post-menopausal women who had high arterial stiffness at the study’s start. Similarly, a 2015 clinical trial demonstrated that Vitamin K2 supplementation significantly reduced arterial stiffening in healthy post-menopausal women over a three-year period. However, some studies, especially smaller or short-term ones, have not found a direct effect of Vitamin K2 supplementation on blood pressure or lipid levels, indicating a need for more extensive, long-term controlled research.
Dietary Sources of Vitamin K2
For those considering increasing their Vitamin K2 intake, dietary sources include:
Natto (exceptionally rich in MK-7, providing over 1100 mcg per 3.5 ounces)
Gouda cheese (around 65.6 mcg per 100g)
Blue cheese (up to 440 mcg per 3.5 ounces)
Egg yolks (15.5 mcg per 3.5 ounces)
Goose liver pate (369 mcg per 3.5 ounces)
Supplementation Considerations
While there is no universally established recommended daily allowance specifically for Vitamin K2, some studies using dosages around 180 mcg/day of MK-7 have shown benefits. Vitamin K2 supplements are generally considered safe and have a low potential for toxicity, even at relatively high doses. However, consult a healthcare professional before starting any new supplement, especially for individuals taking anticoagulant medications like warfarin. Vitamin K2 can reduce the effectiveness of warfarin, and consistent intake of Vitamin K is crucial to avoid fluctuations in the medication’s effects.