Products
Vitamin K2 is commercially available as a dietary supplement in the form of capsules and drops, among others. It is also combined with vitamin D3 fix (D3K2). It occurs naturally, for example, in chicken, egg yolks, dairy products, certain cheeses, and liver, and is produced by microorganisms during fermentation. It is also found in Nattō, a Japanese food made from fermented soybeans. More important for nutrition is vitamin K1 (phytomenadione), which is found in green vegetables.
Structure and properties
Vitamin K2 is the name given to a group of 2-methyl-1,4-naphthoquinone derivatives that differ in the length of their side chain or the number of isoprene units. They are also called menaquinones and are formed by bacteria. Typical representatives are menaquinone-7 (abbreviation: MK-7, C46H64O2, Mr = 649.0 g/mol) and menaquinone-4 (MK-4, menatetrenone). Vitamin K2 belongs to the lipophilic (fat-soluble) vitamins and is photosensitive. Vitamin K1 and vitamin K2 differ in the side chain.
Effects
Vitamin K2 is required in the body, on the one hand, as a cofactor of the enzyme gamma-glutamylcarboxylase for blood clotting (K stands for coagulation). On the other hand, it plays an indirect role in promoting bone formation and inhibiting bone resorption. Vitamin K2 is involved in the post-translational modification (gamma-carboxylation) of proteins such as osteocalcin formed by osteoblasts. Osteocalcin binds calcium from the blood and plays an important role in bone formation.
Indications for use
As a dietary supplement for the maintenance of normal bone. In Japan, vitamin K2 is approved for the prevention and treatment of osteoporosis. Several small studies have found positive effects on bone density in postmenopausal women and other patient groups (e.g., glucocorticoid therapy).
Dosage
According to the package insert. Dosage is in the microgram range. Vitamin K2 is taken as a supplement usually once a day. It can be combined with calcium and vitamin D3.
Contraindications
- Hypersensitivity
- Treatment with vitamin K antagonists
For complete precautions, see the drug label.
Interactions
Drug-drug interactions may occur with vitamin K antagonists. High doses of vitamin K may reverse the effects of anticoagulants.
Adverse effects.
Few adverse effects were observed when prescribed doses were taken.
