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| Key points | Details to remember |
|---|---|
| 🧬 Definition | The most active form of vitamin K2, with a long half-life. |
| 💪 Role | Directs calcium to the bones and prevents its deposition in the arteries. |
| ☀️ Synergy | Complements the action of vitamin D3 on the synthesis of bone proteins. |
| ⚖️ Dosage | MK-7: 100–200 µg/day, D3: 1,000–4,000 IU/day. |
| 🥬 Sources | Natto, aged cheeses and dedicated supplements. |
| 🔗 Absorption | Requires sufficient intake of lipids and minerals such as magnesium. |
When discussing bone health, vitamin D3 has stolen the spotlight for years. However, in the absence of vitamin K2, and more precisely its MK-7 form, the activation of proteins that ensure a strong skeleton remains incomplete. From this perspective, understanding the combined intake of these two nutrients proves essential for anyone wishing to optimize their bone capital and preserve mobility in the long term.
Sommaire
What is vitamin K2 MK-7 ?
Vitamin K2 comes in several menaquinones (MK-4 to MK-13), of which MK-7 is the most studied for its properties. Of microbiological origin, it differs from K1 (phylloquinone) found in green vegetables, both in its bioavailability and its prolonged half-life, which can exceed 72 hours. This characteristic allows for daily administration without major fluctuations in blood levels, unlike MK-4 which requires more frequent dosages.
Biological role and mechanism of action
Activation of vitamin K-dependent proteins
At the heart of K2 MK-7’s action is the activation of prothrombin and especially osteocalcin, a protein synthesized by osteoblasts. Without sufficient MK-7 intake, osteocalcin remains undercarboxylated and unable to bind calcium in the bone matrix. By stimulating γ-carboxylation, K2 ensures that calcium is captured where it is needed, rather than accumulating undesirably in soft tissues or arteries.
Targeted calcium transport
The true strength of the K2-D3 association lies in a dual mechanism: D3 increases intestinal calcium absorption and osteocalcin production, while MK-7 directs this calcium to the bone. In the absence of this “guiding agent,” arterial calcium deposits are sometimes observed, a factor in vascular stiffening. Clinical studies show a significant reduction in arterial calcification in subjects simultaneously supplemented with D3 and MK-7.
Why avoid isolated intake of vitamin D3 ?
Exclusive intake of D3, even at high doses, does not guarantee that all absorbed calcium is directed to the skeleton. Some patients develop hypercalcemia or even fibrous calcifications if the vitamin K level is insufficient. Hence the importance of a balance between these two nutrients to limit side effects and maximize bone density.
Dosages and practical recommendations
Dosages vary according to age, hormonal status, and weight. As a general rule, for an adult, it is recommended:
- 100 µg to 200 µg of MK-7 per day
- 1,000 IU to 4,000 IU of D3 per day
This range takes into account variable dietary intakes and adapts in case of diagnosed deficiency. It is preferable to spread the intake at each meal containing fats to promote optimal lipid absorption.
Dietary sources and supplementation options
Japanese natto remains the reference for MK-7, with several hundred micrograms per 100 g. Some aged farmhouse cheeses, gorgonzola or brie, also contain it. For D3, sun exposure and fatty fish remain the most effective, but concentrations vary according to season and latitude. Hence the importance of standardized supplements, guaranteeing both quantitative intake and regularity of intake.
Integrating K2 MK-7 and D3 into a global routine
Beyond these two vitamins, other factors such as sufficient magnesium intake and microbiota quality condition assimilation. For example, the bioavailability of magnesium can modulate the conversion of vitamin D into its active form. A complete program will therefore include a balanced mineral profile, a varied diet, and regular physical activity to stimulate bone turnover.
FAQ
What is the difference between vitamin K1 and K2 MK-7 ?
K1, derived from green vegetables, mainly participates in blood clotting. K2 MK-7, of bacterial origin, focuses on activating bone and vascular proteins, with a longer half-life.
Why combine vitamins K2 MK-7 and D3 ?
D3 promotes calcium absorption, while MK-7 directs this calcium to the bones, preventing its deposition in the arteries. Their synergy optimizes bone and vascular health.
What dosage of MK-7 and D3 should be chosen ?
Generally, 100–200 µg of MK-7 and 1,000–4,000 IU of D3 per day are recommended, ideally taken with meals rich in lipids.
Are side effects possible ?
Both vitamins are well tolerated. At high doses and in cases of imbalance between D3 and MK-7, hypercalcemia or digestive disorders may occur. Always follow the recommendations.
Where is the MK-7 form naturally found ?
Japanese natto remains the most concentrated source. Some aged cheeses and fermented liver also provide MK-7, but to a lesser extent.
