Quick Summary

Vitamin K2 MK-7, also known as menaquinone-7 (MK-7), is a fat-soluble form of vitamin K, part of the vitamin K2 subgroup. It is structurally distinct from vitamin K1 and other menaquinones by its longer side chain, which is thought to influence its bioavailability and half-life in the human body. Vitamin K2 MK-7 plays a role in the vitamin K group’s general functions related to blood clotting and calcium metabolism, although detailed evidence specific to MK-7’s unique effects remains limited. Recommended intake values and upper limits are generally provided for total vitamin K rather than for individual K2 forms like MK-7.

What Is It?

Vitamin K2 MK-7 is one of several menaquinone forms of vitamin K2, distinguished by the length of their isoprenoid side chains. MK-7 typically has seven isoprene units and is naturally produced by bacterial fermentation, commonly found in fermented foods such as natto. It is classified as a fat-soluble vitamin, absorbed and transported alongside dietary fats.

Main Functions in the Body

Vitamin K2 MK-7 is believed to contribute to the activation of vitamin K-dependent proteins involved in blood coagulation and calcium metabolism. These processes help regulate clot formation and potentially influence bone mineralization and vascular health. However, no detailed, form-specific clinical or nutritional evidence summaries were provided to clearly define unique roles attributable to MK-7 distinct from other vitamin K forms.

Recommended Intake and Upper Limit

Recommended daily intake values (RDA or AI) and tolerable upper intake levels (UL) for vitamin K vary by age, sex, and life stage. These values typically refer to total vitamin K intake—including both vitamin K1 and K2 forms—and are established by health authorities based on the collective activity of these forms.

Currently, no specific RDA or UL values for MK-7 alone are defined. Consumers should consider total vitamin K intake from diet and supplements and consult healthcare professionals for individualized guidance.

Best Food Sources

MK-7 occurs naturally in fermented foods, particularly natto—a traditional Japanese soybean product known for its exceptionally high MK-7 content. Other fermented foods and certain cheeses may also contain variable amounts of MK-7 due to bacterial production during fermentation. However, no detailed quantitative food composition data were provided to specify the best sources precisely.

Deficiency: Causes, Symptoms, and Risk Groups

Vitamin K deficiency is uncommon in the general population consuming a varied diet, as vitamin K is widely distributed in many foods. Deficiency may result from inadequate intake, fat malabsorption disorders, or use of certain medications that affect vitamin K metabolism. Symptoms can include increased bleeding risk due to impaired blood clotting.

No specific deficiency symptoms or risk groups were identified uniquely for MK-7 distinct from other vitamin K forms. At-risk groups for vitamin K deficiency broadly include people with malabsorption conditions, those on long-term antibiotic or anticoagulant therapy, and, rarely, newborns.

Supplement Forms

Vitamin K2 MK-7 is commonly available as a dietary supplement, often in softgel or capsule form, dissolved in oil to enhance absorption given its fat-soluble nature. Supplements may vary in dosage and formulation. No specific comparative data on supplement forms, bioavailability, or dosing were provided.

Potential Benefits: What Does the Evidence Say?

Research into vitamin K2 MK-7 suggests it may influence blood coagulation and calcium-related pathways similar to other vitamin K forms. Some studies have investigated MK-7’s role in bone and cardiovascular health, but no detailed evidence summaries were provided here to confirm or quantify such benefits definitively.

EU-authorized health claims: No authorized health claims specific to vitamin K2 MK-7 are currently in place.

Overall, evidence remains insufficient to support claims beyond the known general roles of vitamin K in supporting normal blood clotting and bone health.

Side Effects and Toxicity

Vitamin K2 MK-7 supplements are generally considered safe when consumed within typical dietary supplement ranges. No specific side effects or toxicity data were supplied. No tolerable upper intake level has been formally established for MK-7 or vitamin K in general, although high doses may interact with anticoagulant medications.

Drug and Nutrient Interactions

Supplemental vitamin K can interact with certain medications, especially anticoagulants (e.g., warfarin), potentially reducing their effectiveness by promoting clotting. This interaction applies broadly to vitamin K forms, including MK-7. People using such medications should manage vitamin K intake carefully under medical supervision.

No additional nutrient or drug interactions specific to MK-7 were provided.

Who Should Be Careful?

  • Individuals on anticoagulant or blood-thinning medications should consult healthcare professionals before using MK-7 supplements.
  • People who are pregnant or breastfeeding should seek advice before supplementing, as safety data are not well established.
  • Those with medical conditions or using other medications should discuss vitamin K2 MK-7 supplementation with their healthcare provider.

Frequently Asked Questions

  • Is vitamin K2 MK-7 the same as vitamin K1?

    No. Vitamin K1 (phylloquinone) and K2 (menaquinones) are chemically related but differ in side chain length and sources. MK-7 is a longer-chain form of vitamin K2 with distinct absorption and half-life profiles.

  • Can I get enough MK-7 from diet alone?

    While MK-7 is present mainly in fermented foods like natto, typical Western diets may provide only small amounts. Total vitamin K intake usually comes largely from vitamin K1 in leafy greens and some vitamin K2 forms from various foods.

  • Are MK-7 supplements necessary?

    Supplements may be considered by those looking to support their vitamin K intake, but evidence supporting specific extra benefits of MK-7 supplementation over dietary vitamin K intake is currently limited.

  • Can taking MK-7 supplements cause harm?

    Adverse effects at typical supplemental doses are uncommon, but high intake can interact with blood-thinning medications. Consultation with a healthcare professional is advised before starting supplementation.

Evidence Limitations

  • No detailed study abstracts or official source excerpts with specific clinical or nutritional evidence were provided to establish functions, dosing, food sources, deficiency details, supplementation benefits, or safety profile for Vitamin K2 MK-7.
  • No EU authorized health claims related to Vitamin K2 MK-7 were supplied.
  • Data on recommended intake, deficiency, and supplement forms specific to MK-7 are currently limited or lacking.

Disclaimer

This page provides general information about vitamin K2 MK-7 based on currently available evidence and should not be considered medical advice. Nutritional needs and health conditions vary by individual. People who are pregnant, breastfeeding, have medical conditions, or use medications should consult a healthcare professional before using vitamin K2 MK-7 supplements or making significant dietary changes.

References

Last Reviewed

June 2024