# Vitamin K2 (menaquinone-7, MK-7)

Menaquinone-7 (MK-7) is a long-chain form of vitamin K2. Its side chain has seven isoprene units, which gives it a longer half-life than vitamin K1 (phylloquinone) or MK-4, so it stays in your body longer. Like other vitamin K forms, it acts as a cofactor for the gamma-carboxylation of 'Gla' proteins. Those include osteocalcin (in bone) and matrix Gla protein (in the vascular wall). The dietary sources are limited. By far the richest is natto, a soy food fermented with Bacillus subtilis, with smaller amounts in cheese and fermented dairy. In a 3-year RCT in 244 postmenopausal women, 180 micrograms of MK-7 a day slowed the loss of vertebral height and bone density. The EU has authorized vitamin K claims for normal blood clotting and for maintaining normal bones. But the cardiovascular outcome evidence is still inconsistent.

## Sources

- Knapen MHJ, Drummen NE, Smit E, Vermeer C, Theuwissen E. (2013). Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women. Osteoporosis International. https://doi.org/10.1007/s00198-013-2325-6
- EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). (2009). Scientific opinion on the substantiation of health claims related to vitamin K and maintenance of normal bone and normal blood coagulation. EFSA Journal. https://doi.org/10.2903/j.efsa.2009.1228
- Jadhav N, Ajgaonkar S, Saha P, Gurav P, Pandey A, Basudkar V, Gada Y, et al.. (2022). Molecular pathways and roles for vitamin K2-7 as a health-beneficial nutraceutical: challenges and opportunities. Frontiers in Pharmacology. https://doi.org/10.3389/fphar.2022.896920

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