Vitamin K2 (Menaquinone)

Vitamin K2 (Menaquinone) is distinct from Vitamin K1 (found in leafy greens and involved in blood clotting). K2 is found primarily in fermented foods like natto, aged cheeses, and fermented dairy — foods largely absent from modern Western diets.

The most effective supplemental form is MK-7 (menaquinone-7), derived from natto fermentation. MK-7 has a much longer half-life than MK-4 — staying active in the body for days rather than hours — making it the preferred form for supplementation.

Vitamin K2 activates two critical proteins through a process called carboxylation:

1. Osteocalcin — a protein in bone that binds calcium and incorporates it into the bone matrix, supporting bone density and strength.

2. Matrix Gla Protein (MGP) — a protein found in blood vessel walls that prevents calcium from depositing in arteries. Without adequate K2, MGP remains inactive and calcium accumulates in arterial walls — contributing to arterial stiffness and cardiovascular disease.

This is why D3 and K2 are considered essential partners — D3 increases calcium absorption and K2 ensures that calcium goes to the right places (bones) rather than the wrong places (arteries).

Vitamin K2 MK-7 has an excellent safety profile:

- Very well tolerated with no known toxicity at standard supplemental doses
- Individuals taking warfarin (blood thinner) must consult their doctor — K2 affects clotting pathways
- Other blood thinning medications may also be affected — medical supervision advised
- Generally considered safe during pregnancy at food-equivalent doses
- Fat-soluble — take with a meal containing dietary fat
- May interact with some antibiotics that affect gut bacteria

- Geleijnse et al. (2004) — Rotterdam Study published in Journal of Nutrition found high dietary K2 intake associated with 57% reduction in death from cardiovascular disease and 26% reduction in all-cause mortality.

- Knapen et al. (2013) — Three-year RCT published in Osteoporosis International found MK-7 supplementation significantly improved bone strength and reduced bone loss in postmenopausal women.

- Vermeer et al. (2004) — Research in Thrombosis and Haemostasis demonstrated K2's role in preventing arterial calcification through MGP activation.

- Maresz (2015) — Review in Integrative Medicine concluded that K2 supplementation alongside D3 represents an important strategy for cardiovascular disease prevention.