Sportifs en mouvement au coucher du soleil : énergie et immunité renforcées avec la vitamine D3 K2 MK7

Vitamin D3 K2 MK7: Benefits, Health and Dosage

Written by: Clara B

Published on April 22, 2025

Time to read 5 min

Vitamin D3 and vitamin K2-MK7 form one of the most discussed micronutritional combinations in nutrition. While the biochemical synergy between the two is detailed in our comprehensive guide to vitamin D3 and K2-MK7, this article focuses on a highly practical question: what are the reference serum thresholds, how can dosage be adapted to actual status, and what do leading organizations say about the levels to target?

We review official recommendations, the important nuances that the guidelines themselves add to their own recommendations, and a practical dosage according to profile.

💪 Force Addict Pro Expert Opinion

A blood test for 25(OH)D₃ remains the only reliable way to know where you actually stand before choosing a supplementation dose. Official recommendations themselves are more cautious than is often presented: the Endocrine Society notes, for example, that there is not enough evidence to recommend vitamin D for a cardiovascular protection objective unrelated to calcium, outside its well-established role in bone health. An approach based on individual data is preferable to higher thresholds without sufficient evidence.

What is vitamin D status and how can it be assessed?

Vitamin D status is measured through serum 25-hydroxyvitamin D (25(OH)D), an intermediate metabolite reflecting total body stores — combined dietary intake and skin synthesis. It is this indicator, rather than a theoretical standard dosage, that should guide supplementation.

severe deficiency: generally defined as below 12-20 ng/mL (30-50 nmol/L) depending on the organization;
insufficiency: an intermediate range depending on the thresholds used, generally between 20 and 30 ng/mL;
sufficiency: from 30 ng/mL (75 nmol/L) according to Endocrine Society recommendations;
vitamin D deficiency remains common in the European population in autumn and winter, particularly among people with limited sun exposure;
only a blood test can determine actual status — self-assessment based on symptoms is not reliable.

What official recommendations actually say

The Endocrine Society guideline: more cautious than often presented

Holick et al., in the Endocrine Society's reference guideline, recommend supplementation adapted to age and clinical context for people at risk of deficiency, with serum 25(OH)D testing as the initial diagnostic test for these individuals. An important point, often omitted in popular summaries: the authors explicitly state that there is currently insufficient evidence to recommend systematic screening in people not at risk, or to prescribe vitamin D for the sole purpose of achieving a cardiovascular benefit independent of its role in calcium (Journal of Clinical Endocrinology & Metabolism, DOI). This nuance calls for a more measured interpretation of benefits that are sometimes presented as established.

Vitamin D and immunity: a real but conditional effect

Martineau et al. conducted an individual participant data meta-analysis combining 25 randomized trials (10 933 participants), showing that vitamin D supplementation reduces the risk of acute respiratory infection by an average of 12% across the entire study population. However, the protective effect was markedly greater among those most deficient at baseline (a 70% reduction in risk among those with an initial level <25 nmol/L) than among people who already had sufficient levels. Furthermore, the protective effect was observed only with regular daily or weekly intake, not with high single doses ("bolus") (BMJ, DOI). It is therefore a real benefit, but one that depends heavily on baseline status and method of administration — not a universal guaranteed effect for everyone.

Key takeaways from official recommendations

Available data strongly support the role of vitamin D in bone health and, with important nuances related to baseline status and intake method, in immunity. Non-calcium-related cardiovascular benefits remain insufficiently demonstrated to date according to the reference guidelines themselves — an important point of caution when faced with claims on the subject that can sometimes be overly assertive.

Practical dosage according to profile

General population, unknown status: 1,000 to 2,000 IU/day of D3 in autumn and winter is a reasonable maintenance approach in the absence of a blood test;
Deficiency confirmed by blood test: higher corrective doses over several weeks, to be determined with a healthcare professional based on the specific result;
Athletes with limited sun exposure (indoor training): a blood test is particularly useful for identifying a potential deficiency before adjusting the dose;
Vitamin K2-MK7: 90 to 180 µg/day, a range studied in clinical trials on bone health;
Monitoring: a follow-up blood test after several weeks of correction helps verify that the target has been reached without exceeding safety thresholds.

⚠️ Avoid overdosing

Vitamin D toxicity is rare but real with very high prolonged doses, with a risk of hypercalcemia. Health authorities set upper safety limits beyond which medical supervision becomes necessary. High-dose supplementation without prior blood testing or monitoring is not recommended — this is precisely why testing 25(OH)D before and during correction remains the safest approach.

Comparison of thresholds by context

25(OH)D status	Interpretation	Generally recommended action
< 12 ng/mL (30 nmol/L)	Severe deficiency	Medically supervised correction
12–20 ng/mL (30–50 nmol/L)	Deficiency	Correction recommended
20–30 ng/mL (50–75 nmol/L)	Insufficiency	Maintenance supplementation
> 30 ng/mL (75 nmol/L)	Sufficiency according to the Endocrine Society	Maintenance, no correction needed

What the scientific data say

Holick et al., in the Endocrine Society guideline, establish reference thresholds for vitamin D deficiency and sufficiency and recommend targeted supplementation for people at risk, while highlighting the lack of sufficient evidence for widespread screening or non-calcium-related cardiovascular use (Journal of Clinical Endocrinology & Metabolism, DOI). Martineau et al. confirm a protective effect of vitamin D on respiratory infections, particularly pronounced in deficient individuals and with regular intake rather than bolus dosing (BMJ, DOI). Knapen et al. confirm the relevance of K2-MK7 (180 µg/day) for bone density in postmenopausal women over 3 years (Osteoporosis International). Geleijnse et al. confirm the association between K2 intake and reduced cardiovascular risk in the Rotterdam cohort (Journal of Nutrition).

🛡️ Vitamin D3 + K2-MK7: the Force Addict Pro selection

D3+K2 formulas dosed according to the ranges studied in clinical trials, for supplementation consistent with the available data.

Vitamin D3 + K2 Vitamins & Minerals

To learn more

To further explore essential micronutrients and their role in athletic performance and health:

Scientific references

Holick MF, Binkley NC, Bischoff-Ferrari HA, et al. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. Journal of Clinical Endocrinology & Metabolism. 2011;96(7):1911-1930. https://doi.org/10.1210/jc.2011-0385
Martineau AR, Jolliffe DA, Hooper RL, et al. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. BMJ. 2017;356:i6583. https://doi.org/10.1136/bmj.i6583
Knapen MHJ, Drummen NE, Smit E, Vermeer C, Theuwissen E. Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women. Osteoporosis International. 2013;24(9):2499-2507.
Geleijnse JM, Vermeer C, Grobbee DE, et al. Dietary intake of menaquinone is associated with a reduced risk of coronary heart disease: the Rotterdam Study. Journal of Nutrition. 2004;134(11):3100-3105.

Key takeaways

Actual vitamin D status, determined through a 25(OH)D blood test, remains the most reliable basis for calibrating supplementation — far more so than a standard dose used without verification. Official recommendations themselves (Endocrine Society) are more cautious than some commercial claims suggest, particularly regarding non-calcium-related cardiovascular benefits, for which evidence remains insufficient to date. The effect on immunity is real but depends on baseline status and intake method (daily rather than bolus).

Combined with K2-MK7 at studied doses (90 to 180 µg/day), vitamin D3 remains a relevant micronutritional pillar, provided it is used rigorously — prior assessment, appropriate dosage, and ongoing monitoring. This data-based approach, rather than excessive promises, is what Force Addict Pro supports in its selection of health supplements.

← Go back

Questions fréquentes

Retrouvez les réponses aux questions les plus courantes avant votre achat.

Pourquoi associer la vitamine D3 avec la K2-MK7 plutôt que de prendre la D3 seule ?

La logique repose sur une complémentarité biochimique. La D3 augmente l'absorption intestinale du calcium ; la K2-MK7 contribue à activer les protéines (ostéocalcine, MGP) qui dirigent ce calcium vers les os plutôt que vers les tissus mous. Geleijnse et al. (Journal of Nutrition) ont montré qu'un apport élevé en ménaquinone (K2) était associé à un risque réduit de calcification aortique sévère dans la cohorte Rotterdam. Cette association répond donc à une logique de cohérence physiologique, plus qu'à une nécessité absolue démontrée par des essais combinant directement les deux molécules.

Quelle dose de vitamine D3 est recommandée pour les sportifs selon les recommandations officielles ?

Les recommandations varient selon le statut individuel, ce qui rend un dosage sanguin préalable particulièrement utile. Une insuffisance en vitamine D reste fréquente chez de nombreux sportifs européens, en particulier ceux s'entraînant en intérieur. Holick et al. (Endocrine Society) recommandent une supplémentation adaptée à l'âge et au contexte chez les personnes à risque, avec le dosage sanguin comme test diagnostique de référence plutôt qu'une dose standard appliquée sans vérification.

La forme MK-7 de la vitamine K2 est-elle vraiment supérieure à la forme MK-4 ?

La MK-7 présente une demi-vie nettement plus longue que la MK-4, ce qui permettrait un maintien plus stable des niveaux circulants avec une prise quotidienne unique — c'est l'une des raisons pour lesquelles elle est privilégiée dans les compléments destinés à un usage quotidien simple. Les données comparatives directes entre les deux formes sur des critères cliniques (densité osseuse, santé cardiovasculaire) restent toutefois encore relativement limitées, la MK-7 étant la forme la mieux représentée dans les essais cliniques récents comme celui de Knapen et al.

La vitamine D3 améliore-t-elle réellement la force musculaire et réduit-elle le risque de blessure ?

Les récepteurs VDR (Vitamin D Receptor) présents dans le tissu musculaire suggèrent un rôle physiologique plausible. Plusieurs études observationnelles associent un statut en D3 adéquat à une meilleure force musculaire, en particulier chez les sujets initialement carencés — le bénéfice semble plus marqué lorsque la supplémentation corrige un déficit réel que chez des sportifs déjà bien pourvus, où l'effet additionnel reste moins certain selon les données disponibles à ce jour.

À qui s'adresse prioritairement la supplémentation en vitamine D3 K2-MK7 ?

Principalement aux personnes peu exposées au soleil (entraînement en intérieur, pays nordiques, hiver), aux personnes de plus de 50 ans en lien avec le risque de perte osseuse, et aux personnes ayant un statut carencé confirmé par dosage sanguin. Un dosage préalable de la 25(OH)D reste la démarche la plus rigoureuse pour identifier qui bénéficierait réellement d'une correction, plutôt qu'une supplémentation généralisée sans vérification individuelle.

Peut-on couvrir ses besoins en vitamine D3 et K2 uniquement par l'alimentation ?

C'est difficile pour la D3 et plus difficile encore pour la K2-MK7 spécifiquement. La D3 se trouve dans les poissons gras, les œufs et certains produits enrichis, mais les apports alimentaires courants couvrent rarement les besoins de la majorité des personnes en automne-hiver. La K2-MK7 est présente principalement dans le natto (soja fermenté japonais), aliment peu consommé en Europe ; les fromages et produits laitiers fermentés apportent surtout d'autres formes de K2 en quantités modestes. La supplémentation reste donc une option pertinente pour atteindre les niveaux étudiés dans les essais cliniques.