Why Vitamin K2 Deserves More Attention Than It Gets

Most people have heard they should be taking vitamin D. Fewer have heard much about vitamin K2 - and that's a problem.

Because if you're taking vitamin D3 without K2, you may not be getting the full picture.

You may have seen vitamin D3 supplements often being paired with vitamin K, and it can even be found in our ImmunoDrops which pairs vitamin D3 (cholecalciferol) with vitamin K2 (i.e. MK-7).

But why is that?

Together, vitamin D3 and K2 support bone strength, heart health, immune function, and inflammation regulation.

What is Vitamin K? 

Vitamin K has long been associated with normal blood clotting - that's actually how it got its name, from the German word for coagulation. But vitamin K impacts many systems throughout the body other than just blood clotting.  

Research from the University of Guelph's immunology team confirms that vitamin K plays critical roles in bone health, cardiovascular protection, brain function, immune modulation, inflammation control, and more.¹  Vitamin K allows an enzyme called γ-glutamylcarboxylase (VKDC) to activate Gal proteins that help bind calcium, and regulate blood clotting and immune system activity including inflammation. Additionally, there are various forms of vitamin K, and not all of them are equal as different forms vary in their level of absorption and distribution. 

The most bioavailable and potent form of vitamin K is vitamin K2, the best being MK-7, which can be made by bacteria found in our gut and fermented foods like natto². Additionally, there is currently no established upper limit for vitamin K1 or K2 due to its low potential for toxicity in humans^3,4. 

Vitamin K2 is also safer than synthetic forms like vitamin K3 (menadione), which are not used in human supplements due to their reported adverse effects of hemolysis and liver toxicity⁵. Other forms such as vitamin K1 (phylloquinone) are synthesized by cyanobacteria, which are naturally found in dark leafy greens, but have low bioavailability. 

Overall, while many forms of vitamin K exist, vitamin K2 forms stand to be most utilized in supplements due to their high bioavailability, potency and safety in humans. 

How Vitamin K2 Improves Calcium Utilization 

Vitamin D3 and K2 are often paired together because they work synergistically. Vitamin D3 alone increases how much calcium your body absorbs from food by getting it into your bloodstream. However, without Vitamin K2, excess calcium can build up in the bloodstream, leading to vascular calcification and the risk of atherosclerosis⁶. 

On the other hand, with vitamin K2, it facilitates activation matrix Gla Protein (MGP), a large complex molecule that binds to calcium, preventing coronary calcification⁷. In fact, studies have shown that those with high intake of Vitamin K2 have reduced risk of coronary calcification and cardiovascular disease, while those with Vitamin K deficiency had reduced levels of activated MGP, and therefore, increased incidences of arterial calcification^8,9. Like MGP, osteocalcin is another Gla protein activated by vitamin K2, which binds to calcium to pull it into bone tissue¹. Interestingly, both MGP and osteocalcin genes contain vitamin D response elements, which means optimal vitamin D levels are also required for MGP and osteocalcin synthesis.

So, you could be getting enough vitamin D3, but without K2, this could result in simultaneously having weaker bones and calcified arteries. Likewise, without optimal vitamin D3 levels, several Gal proteins can't effectively function to regulate calcium transport.

Combined D3 and K2 supplementation has shown measurable improvements in bone mineral density and bone strength compared to D3 alone¹⁰. A three-year study found that K2 supplementation reduced arterial stiffness - something D3 alone didn't accomplish¹¹. 

Vitamin K also qualifies as an immunoceutical - a naturally occurring compound that directly supports immune competence. Research from ImmunoCeutica's scientists at the University of Guelph places vitamin K2 in this category alongside vitamin D3, selenium, and other key micronutrients¹².

How Vitamin K3 Influences Inflammation 

Vitamin K3 can help with calcium utilization when paired with vitamin D3, but did you know it has also been associated with helping reduce inflammatory markers? 

A recent 2022 study showed that supplementation with MK-7 reduced inflammatory markers in those with type 2 diabetes¹³. Also, an in vitro study, meaning research done with cells, pre-treatment with MK-7 on cells resulted in a reduction of inflammatory biomarker expression, such as TNFα, IL-1α, and IL-1β¹⁴. Together, these findings point to an interesting area of research - how vitamin K2 forms might interact with the body’s inflammation pathways and overall metabolic balance.

The Form Matters

Not all vitamin K2 is the same. MK-7 is the preferred form for supplementation - it stays in circulation longer than MK-4, which means more consistent levels throughout the day with once-daily dosing.

Typical daily amounts

These are general ranges - the right vitamin D dosage depends on your current levels. A vitamin D blood test is the most reliable way to know where you stand.

• Vitamin D3: 2,000–4,000 IU (ideally guided by a blood test)
• Vitamin K2 as MK-7: 100–200 mcg

If you're taking blood thinners like warfarin or Coumadin, speak with your healthcare provider before adding K2. Even low doses of MK-7 can interfere with anticoagulant therapy.¹

Who Should Pay Attention

The D3+K2 pairing matters most for:

• Older adults, since both vitamin D and K2 levels tend to decline with age
• Postmenopausal women facing higher osteoporosis risk
• Anyone taking higher-dose vitamin D (4,000 IU or more)
• People with cardiovascular concerns
• Anyone already supplementing with calcium

You may also want to pay attention if you're experiencing vitamin D deficiency symptoms like fatigue, bone pain, or frequent illness. In Canada, most adults fall short of recommended vitamin D intake - especially through winter months, with deficiency rates particularly high in Ontario, Alberta, and BC.

Beyond Bones and Heart Health

The benefits don't stop at the skeleton and circulatory system. 

Both vitamin D3 and K2 have roles in immune regulation, and research increasingly suggests that the two nutrients support  each other's effects - particularly for the circulatory and skeletal systems.¹ There's also emerging evidence pointing to benefits for dental health, insulin sensitivity, and inflammatory regulation.

The short version is vitamin D3 gets calcium into your body. Vitamin K2 makes sure it ends up where it belongs. They work together — and taking one without the other leaves something on the table.

If you're looking for the best vitamin D supplement in Canada that pairs both nutrients at clinically relevant doses, our ImmunoDrops D3+K2 combines cholecalciferol and MK-7 - immunologist-formulated and available across Canada.

Shop D3+K2 here

Reviewed by Nancy Gao, M.Sc., Animal Biosciences

References

1. Sadler RA, Shoveller AK, Shandilya UK, Charchoglyan A, Wagter-Lesperance L, Bridle BW, Mallard BA, Karrow NA. (2024). Beyond the Coagulation Cascade: Vitamin K and Its Multifaceted Impact on Human and Domesticated Animal Health. Current Issues in Molecular Biology, 46(7), 7001–7031. https://doi.org/10.3390/cimb46070418
2. Bus, K., & Szterk, A. (2021). Relationship between Structure and Biological Activity of Various Vitamin K Forms. Foods, 10(12), 3136. https://doi.org/10.3390/foods10123136
3. Hwang, S., Choi, M., Lee, H., & Han, J. (2024). Safety evaluation of vitamin K2 (menaquinone-7) via toxicological tests. Scientific Reports, 14(1), 5440. https://doi.org/10.1038/s41598-024-56151-w
4. National Institutes of Health (NIH) Office of Dietary Supplements (ODS). (2021). Vitamin K [Fact sheet]. https://ods.od.nih.gov/factsheets/VitaminK-HealthProfessional/#h14
5. Marles, R. J., Roe, A. L., & Oketch-Rabah, H. A. (2017). US Pharmacopeial Convention safety evaluation of menaquinone-7, a form of vitamin K. Nutrition Reviews, 75(7), 553–578. https://doi.org/10.1093/nutrit/nux022
6. Tang, F. T., Chen, S. R., Wu, X. Q., Wang, T. Q., Chen, J. W., Li, J., Bao, L. P., Huang, H. Q., & Liu, P. Q. (2006). Hypercholesterolemia Accelerates Vascular Calcification Induced by Excessive Vitamin D via Oxidative Stress. Calcified Tissue International, 79(5), 326–339. https://doi.org/10.1007/s00223-006-0004-8
7. Beulens, J. W. J., Booth, S. L., Van Den Heuvel, E. G. H. M., Stoecklin, E., Baka, A., & Vermeer, C. (2013). The role of menaquinones (vitamin K2 ) in human health. British Journal of Nutrition, 110(8), 1357–1368. https://doi.org/10.1017/S0007114513001013
8. Beulens, J. W. J., Bots, M. L., Atsma, F., Bartelink, M.-L. E. L., Prokop, M., Geleijnse, J. M., Witteman, J. C. M., Grobbee, D. E., & Van Der Schouw, Y. T. (2009). High dietary menaquinone intake is associated with reduced coronary calcification. Atherosclerosis, 203(2), 489–493. https://doi.org/10.1016/j.atherosclerosis.2008.07.010
9. Cranenburg, E. C. M., Vermeer, C., Koos, R., Boumans, M.-L., Hackeng, T. M., Bouwman, F. G., Kwaijtaal, M., Brandenburg, V. M., Ketteler, M., & Schurgers, L. J. (2008). The Circulating Inactive Form of Matrix Gla Protein (ucMGP) as a Biomarker for Cardiovascular Calcification. Journal of Vascular Research, 45(5), 427–436. https://doi.org/10.1159/000124863
10. Knapen, M. H. J., Drummen, N. E., Smit, E., Vermeer, C., & Theuwissen, E. (2013). Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women. Osteoporosis International, 24(9), 2499–2507. https://doi.org/10.1007/s00198-013-2325-6
11. Theuwissen, E., Cranenburg, E. C., Knapen, M. H., Magdeleyns, E. J., Teunissen, K. J., Schurgers, L. J., Smit, E., & Vermeer, C. (2012). Low-dose menaquinone-7 supplementation improved extra-hepatic vitamin K status, but had no effect on thrombin generation in healthy subjects. British Journal of Nutrition, 108(9), 1652–1657. https://doi.org/10.1017/S0007114511007185
12. Tieu S, Charchoglyan A, Wagter-Lesperance L, Karimi K, Bridle BW, Karrow NA, Mallard BA. (2022). Immunoceuticals: Harnessing Their Immunomodulatory Potential to Promote Health and Wellness. Nutrients, 14(19), 4075. https://doi.org/10.3390/nu14194075
13. Karamzad, N., Faraji, E., Adeli, S., Sullman, M. J. M., & Pourghassem Gargari, B. (2022). The effect of menaquinone-7 supplementation on dp-ucMGP, PIVKAII, inflammatory markers, and body composition in type 2 diabetes patients: A randomized clinical trial. Nutrition & Diabetes, 12(1), 15. https://doi.org/10.1038/s41387-022-00192-5
14. Pan, M.-H., Maresz, K., Lee, P.-S., Wu, J.-C., Ho, C.-T., Popko, J., Mehta, D. S., Stohs, S. J., & Badmaev, V. (2016). Inhibition of TNF-α, IL-1α, and IL-1β by Pretreatment of Human Monocyte-Derived Macrophages with Menaquinone-7 and Cell Activation with TLR Agonists In Vitro. Journal of Medicinal Food, 19(7), 663–669. https://doi.org/10.1089/jmf.2016.0030

This article is for educational purposes and does not constitute medical advice. Consult a healthcare professional before making changes to your supplement routine.