Vitamin K2 (MK-7)

What it is

Vitamin K2, or menaquinone, is a fat-soluble vitamin from the K group, a cofactor for key carboxylases involved in activating calcium-binding proteins. It exists in several isoforms: MK-4 (short chain, fast action) and MK-7 (long chain, prolonged action, better bioavailability). MK-7 is synthesised during bacterial fermentation (the soy product natto is the richest dietary source, up to 1000 mcg/100 g) and is found in hard cheeses, egg yolks, and chicken liver.

The discovery of vitamin K2's role in hard tissue mineralisation came in the 1990s: researchers found that mice with the MGP (matrix Gla protein) gene knocked out died within the first weeks of life from massive arterial and cartilage calcification. This proved that MGP is a direct inhibitor of ectopic calcification, and its activation depends entirely on vitamin K2.

How it works

The mechanism of vitamin K2 is effected through gamma-carboxylation of specific proteins (Gla-proteins): osteocalcin (synthesised by osteoblasts and odontoblasts) and matrix Gla-protein (MGP). The carboxylation reaction of glutamate residues in these proteins is only possible with vitamin K2 as cofactor for the relevant carboxylase.

Carboxylated osteocalcin acquires high affinity for hydroxyapatite crystals and integrates into the protein matrix of dentine and bone, facilitating calcium binding specifically in hard tissues. Non-carboxylated osteocalcin (in K2 deficiency) cannot bind apatite — calcium is "lost" into the systemic circulation.

MGP prevents pathological calcification of soft tissues (arteries, cartilage, kidneys). This is why vitamin K2 deficiency is associated with a paradox: simultaneous osteoporosis (insufficient bone mineralisation) and atherosclerosis (arterial calcification).

Efficacy

Beulens et al. (2013), reviewing clinical data, confirmed that MK-7 at 90–180 mcg/day significantly reduces undercarboxylated osteocalcin levels (a biomarker of K2 deficiency) and improves bone mineral density in long-term studies. For teeth specifically: studies of K2 deficiency in children correlate with disturbances in hard dental tissue formation (analogous to hypomineralisation).

Synergy with vitamin D3 is fundamental: D3 increases osteocalcin synthesis, K2 ensures its carboxylation. Without K2, increasing D3 may raise undercarboxylated osteocalcin with no real improvement in mineralisation. The D3 + K2 combination is a clinically validated pair.

Safety

Vitamin K2 (MK-7) is safe at recommended doses. No upper tolerable intake level has been established (no toxicity data at doses up to 1000 mcg/day in clinical observations). The only significant interaction is antagonism with warfarin and other vitamin K antagonist anticoagulants. Patients on warfarin should consult a physician before supplementation.

Role in the QDRO formula

In QDRO toothpastes, vitamin K2 is not included for the same reason as D3: topical application delivers no physiologically meaningful effect. The systemic biochemistry of Gla-protein carboxylation requires oral intake and hepatic metabolic processing.

Strategic conclusion: vitamins D3 and K2 form a natural axis for a nutraceutical complement to the QDRO v.pro product line. The narrative "remineralisation from outside (paste) + remineralisation from within (D3+K2)" is a unique positioning that can occupy a vacant niche in the Russian oral care market.