Menaquinone 7
Also known as: MK-7, Vitamin K2 (menaquinone form), Menaquinone-7
Overview
Menaquinone-7 (MK-7) is a long-chain menaquinone, a specific subtype of Vitamin K2, naturally occurring in fermented foods like natto and certain cheeses. It is a fat-soluble vitamin primarily recognized for its significant role in supporting cardiovascular health, bone metabolism, and potentially glycemic control. MK-7 stands out among other Vitamin K forms, such as K1 and MK-4, due to its superior bioavailability and extended half-life in the body, allowing for more sustained biological activity. Research on MK-7 is robust, with a substantial body of evidence including multiple randomized controlled trials (RCTs) and systematic reviews/meta-analyses, indicating moderate to high-quality evidence for its benefits. Its mechanism involves activating key proteins essential for calcium regulation in both vascular tissues and bones, making it a crucial nutrient for maintaining overall physiological balance.
Benefits
MK-7 offers several evidence-based benefits, primarily in cardiovascular and bone health. For cardiovascular health, MK-7 supplementation significantly attenuates arterial stiffness, particularly in post-menopausal women with increased vascular stiffness. Studies have shown improvements in blood pressure (reductions of ~3-4.5%) and increased vascular compliance (~12-13%) after one year of supplementation. A systematic review and meta-analysis further indicate that Vitamin K supplementation, including MK-7, can slow the progression of coronary artery calcification (CAC), a key marker of vascular disease. In terms of bone health, a meta-analysis of multiple trials demonstrates that menaquinone reduces fracture risk (hip fractures by 6%, vertebral fractures by 13%, all nonvertebral fractures by 9%) and improves bone mineral density. Beyond these, a recent meta-analysis suggests MK-7 may improve glycemic indices and reduce total cholesterol levels, indicating potential metabolic benefits. Other systematic reviews suggest positive effects on weight, BMI, and inflammatory markers, though results can vary.
How it works
MK-7 functions as a vital cofactor for the enzyme γ-glutamyl carboxylase. This enzyme is responsible for activating vitamin K-dependent proteins (VKDPs), notably matrix Gla-protein (MGP) and osteocalcin. Activated MGP plays a crucial role in inhibiting vascular calcification by binding to calcium ions, thereby protecting blood vessels from hardening. Concurrently, activated osteocalcin is essential for proper bone mineralization, facilitating the incorporation of calcium into bone tissue. MK-7's longer half-life compared to other vitamin K forms ensures sustained carboxylation activity, leading to more prolonged and effective activation of these critical proteins. Being fat-soluble, MK-7 is absorbed in the intestine in the presence of dietary fats and subsequently transported throughout the body via lipoproteins, ensuring its delivery to target tissues.
Side effects
Menaquinone-7 (MK-7) is generally well-tolerated, with a favorable safety profile observed in clinical trials at doses up to 360 mcg/day. Common side effects are rare and typically mild, primarily involving minor gastrointestinal discomfort. The most significant safety consideration for MK-7 is its interaction with anticoagulant medications, specifically vitamin K antagonists like warfarin. MK-7 can antagonize the effects of warfarin, potentially reducing its efficacy and increasing the risk of blood clot formation. Therefore, individuals on warfarin therapy should not take MK-7 without strict medical supervision and regular monitoring of their coagulation status. There are no other significant drug interactions reported. While extensive safety data for special populations such as pregnant women and children are limited, no major concerns have been reported in adult populations. Overall, MK-7 is considered safe for most healthy adults when used appropriately.
Dosage
The minimum effective dose of MK-7 for demonstrating vascular and bone benefits is approximately 180 mcg/day. The optimal dose range, as observed in most randomized controlled trials, typically falls between 180–360 mcg/day. While a firm maximum safe dose has not been definitively established, doses up to 360 mcg/day have been consistently well-tolerated in studies. For optimal absorption, MK-7 should be taken with meals that contain dietary fat, as it is a fat-soluble vitamin. MK-7 is generally preferred over MK-4 due to its superior bioavailability and longer half-life, which contributes to a more sustained effect in the body. Co-administration with fat-containing meals is highly recommended to enhance its absorption and efficacy.
FAQs
Does MK-7 interact with blood thinners?
Yes, MK-7 can reduce the effectiveness of warfarin. If you are on warfarin, medical supervision is required before taking MK-7 to avoid adverse interactions.
How soon can one expect to see benefits from MK-7?
Improvements in vascular stiffness typically become noticeable after 6-12 months of consistent supplementation, while bone health benefits may take a longer duration to manifest.
Is MK-7 superior to Vitamin K1?
Yes, MK-7 generally has superior bioavailability and a longer half-life compared to Vitamin K1, making it more effective for delivering benefits to extrahepatic tissues like bones and blood vessels.
Research Sources
- https://academic.oup.com/eurheartj/article/44/Supplement_2/ehad655.2621/7391763 – This RCT found that MK-7 supplementation significantly reduced arterial stiffness and blood pressure in post-menopausal women over one year. The study highlights MK-7's potential in improving vascular health, particularly in a vulnerable population.
- https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2023.1115069/full – This systematic review and meta-analysis investigated the effect of Vitamin K supplementation on vascular calcification. It concluded that Vitamin K, including MK-7, can slow the progression of coronary artery calcification, despite some heterogeneity among the included studies.
- https://pubmed.ncbi.nlm.nih.gov/40054729/ – This systematic review and meta-analysis of RCTs indicated that MK-7 supplementation may improve glycemic control and reduce total cholesterol levels. The findings suggest potential metabolic benefits of MK-7, though variability in study designs was noted.
- https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/410550 – This meta-analysis of seven RCTs demonstrated that menaquinone supplementation significantly reduces the risk of hip, vertebral, and all nonvertebral fractures, while also improving bone mineral density. It provides strong evidence for MK-7's role in bone health.
- https://www.cambridge.org/core/journals/journal-of-nutritional-science/article/effect-of-vitamin-k-supplementation-on-cardiovascular-risk-factors-a-systematic-review-and-metaanalysis/0F16EF6952E35875EE28AC0DA5974B5E – This systematic review and meta-analysis of 17 RCTs explored the effect of Vitamin K supplementation on various cardiovascular risk factors. It found that Vitamin K, including MK-7, may positively influence weight, BMI, blood pressure, and inflammatory markers, although results varied across studies.
