How can the functional synergy between vitamins D3 and K2 have a positive impact on health?

| By Celine Torres-Moon

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How can the functional synergy between vitamins D3 and K2 have a positive impact on health?

Important news: With so many people taking vitamin D, they may be short-changing themselves by not taking a vital companion nutrient that’s less in the limelight—vitamin K. Here are some little-known facts about their interactions from our friends at Protocol for Life Balance . . . 

—Dr. Hoffman

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Vitamins D and K are both fat-soluble vitamins that play central roles in calcium metabolism.* Vitamin D promotes the production of vitamin K-dependent proteins, which require activation by vitamin K  in order to function properly.*1

In regards to bone health, in experimental models, the interactions between vitamins D and K are being extensively studied and our current understanding is that vitamin D enhances vitamin K-dependent bone protein concentrations and induces bone formation by stimulating cells in charge of the production of new bone tissue.* Furthermore, it appears that vitamin K can interact with the vitamin D receptors present inside cells and affect vitamin D-related functions within cells.* More fundamental research is needed, however, to fully understand the relationship between vitamins D and K within cells with respect to the support of healthy bone tissue metabolism.* Some clinical studies comparing the effect of a combined vitamin D and K supplementation to either vitamin alone have shown better results than expected on bone mass density for the combined supplementation than either vitamin given separately, especially for postmenopausal women.* However, the exact ratio of vitamin D to K and the best form of vitamin K to be used to obtain the best results on bone health is still open for debate. 1

When it comes to cardiovascular health, the combination of vitamins D and K has also triggered a lot of attention from the scientific research community. Vitamins D and K are also interrelated through the regulation of proteins that are powerful regulators of vascular calcification.* While it is not fully understood how vitamins D and K affect cardiovascular health at the cellular level, observational population studies have indicated that the combination of low serum vitamin D and low serum vitamin K was associated with higher systolic and diastolic blood pressure (while remaining within normal range).* This observation gives a valuable insight on how both vitamin D and K could be involved in cardiovascular health.*2

Furthermore, in an interventional study investigating the combined effect of vitamins D and K on vascular function and calcification in healthy postmenopausal women, after 3 years of supplementation with 1000 μg/d vitamin K1 + 320 IU vitamin D, the vitamin D+K group maintained vessel wall characteristics of a healthy carotid artery, whereas the control group and the vitamin D-only group did not show any positive effect on the structure of carotid arteries.* These few studies show some potential for the combined effect of vitamins D and K versus vitamin D alone. However, it should be noted that, so far, very few clinical studies have been conducted in this field and that there is still a lot to discover – most notably, what is the optimal vitamin D to K ratio, and what is the best form of vitamin K to be used to achieve the cardiovascular benefits of combined vitamin D and K supplementation.* 1

Other health benefits related to vitamin D and K supplementation are under investigation, especially their combined effect on insulin metabolism, endocrine function, and oxidative stress.* 1 

Lastly, recently published pre-clinical data suggest that high-dose vitamin D depletes extrahepatic vitamin K stores by strongly increasing the production of specific vitamin K-dependent proteins, leading to the acceleration of elastin fiber calcification and degradation.* Vitamin D administration in a state of vitamin K functional deficiency may thereby alter pulmonary and vascular tissues, since these tissues are naturally rich in elastin fibers.* These observations from laboratory experiments seem to correlate with observations in humans, which indicate that vitamin D supplementation could negatively impact the health of vitamin K-insufficient individuals.* It may therefore be prudent to first supplement with vitamin K before introducing vitamin D supplementation in those who are vitamin D-deficient, and only add vitamin D when extrahepatic vitamin K status has been restored.

Current evidence supports the notion that joint supplementation with vitamins D and K might be more effective than the consumption of either alone for bone and cardiovascular health.* As more is discovered about the powerful combination of vitamins D and K, it gives a renewed reason to supplement your diet with both vitamin D3 and K2 alongside a healthy diet including a variety of foods such as vegetables and fermented dairy for bone and cardiovascular health.*1 However, many questions remain open when it comes to supplementation:  the right vitamin D and K ratio and which forms of vitamin K will generate the best results for cardiovascular and bone health.*

Protocol For Life Balance®, a brand of high-quality dietary supplements, offers several vitamin D and K combinations as well as several potencies of stand-alone vitamins D and K; plus several forms of vitamin K, including menaquinone-4 and -7 (MK-4 and MK-7). This wide range of products allows for customized supplementation to meet the needs of each individual seeking to support both bone and cardiovascular health.* Consulting a healthcare professional to tailor vitamin D and K supplementation is recommended to optimize the health benefits of vitamin D and K combinations.


  1. van Ballegooijen AJ, Pilz S, Tomaschitz A, Grübler MR, Verheyen N. International Journal of Endocrinology. 2017;2017.
  2. Mayer O, Jr., Seidlerova J, Wohlfahrt P, et al. J Nutr Biochem. 2017;46:83-89.

* These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.


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