INTRODUCTION
There is a great deal of evidence surrounding the benefits of vitamin D3 in our diets and bodies. If you have been my client/reading my articles over the years, you would no doubt be aware that I have been vocal on optimal vitamin D3 consumption (whether it’s from the sun, food, supplementation, or a combination of all of these).
Here are a couple of articles (there are many more just search “vitamin D” on McIsaacHealth.com) to bring you up to speed:
LINK: Vitamin D: Types, Utility, Screening, and Optimal Dosing
LINK: Vitamin D Supplementation: When, How, and Why?
THANKS. BUT YOUR TITLE IS TALKING ABOUT VITAMIN K2 AS WELL. WHY?
It turns out that vitamin D has MANY roles in the body; one of those is to help “pull” calcium (Ca) from your food/intestines across the gut lining and into the blood.1 This sounds like a great thing (of course it is). However, once Ca makes it across into the blood, what then? Keep reading.
VITAMIN K2: THE ULTIMATE CALCIUM TRAFFIC COP
So, Ca is finally in the blood…but that’s not quite good enough. Calcium needs a little guidance and direction in your vessels, like a traffic cop! That “guidance” is where vitamin K2 (not vitamin K1) shines brightly, among other roles…have a look at the link below).
LINK: Vitamin K2 Function
OKAY. VITAMIN K2 DIRECTS CALCIUM….WHERE?
K2 specifically directs calcium towards bone where it is needed most to help develop strong and resilient bones. IF you are low in K2 and consuming vitamin D3, evidence suggests that calcium can build up in your vasculature (your blood vessels and their arrangement in organs they supply).2
NERD ALERT (skip if you want to): Vitamin D3 and vitamin K2 interact with proteins (made of amino acids) which make matrix GLA protein (MGP) and osteocalcin.2(2) “Why is this important” you might say? These proteins help keep your vessels free of calcification! However, MGP and osteocalcin need to have a little part added to them in order to carry out their function properly.2(2) That is, MGP and osteocalcin need to be carboxylated first (i.e., they need a carboxyl group added)…See the image above.
SO I NEED K2 WITH D3. HOW MUCH?
Studies that have been conducted used dosages of K2 anywhere from 90-360 mcg/day.2(9) Furthermore, Iwamato3 noted that higher doses (i.e., 450 mcg/day of K2) appeared to have no toxic effects suggesting its safety and longer-term use. Finally, 90-120 mcg/day (close to the general RDI of vitamin K) successfully promoted osteocalcin carboxylation (the traffic cop).4
SECONDARY NERD ALERT
Certain medications can inhibit the absorption of vitamin K.5 Have a look above infographic.
ALRIGHT. CALCIFIED VESSELS BAD. WHERE IS THIS K2 FOUND?
Great question! K2 can be found in quite a few places actually. For example, eggs contains anywhere between approximately 67-192 mcg of K2 per 100 grams of yolk.6 To get a handle on a 100-gram serving… the average egg yolk is about 17 grams, so you’d need 6 eggs (yolks) a day to get reach these K2 levels.7 The good news, however, is that you don’t HAVE to stuff yourself with just eggs to get K2; you can also get it from a host of other tasty sources too. Liver, meat, and fermented foods (i.e., cheese, natto). See the infographic above for a little more insight!
I’M WORRIED I MIGHT NOT BE GETTING ENOUGH VITAMIN K2 IN MY FOOD
No problem. Remember to do your best and use the internet (reputable places remember) to get a handle on how much K2 is in a serving of a particular food too! But if you are still in doubt, you can certainly supplement with some K2 as well. You can do this especially because there is no known toxicities associated with high doses of K2 (mentioned previously).8Remember to always strive to reach your nutrient goals from real food, and use supplementation as an insurance policy. Having said that, 120 mcg of supplemental K2 with your vitamin D3 is a reasonable choice, and this is a dose often found in stores.
CONCLUSIONS
There you have it. Now you are hopefully a little more informed about the value of vitamin D3 and its synergistic effects with vitamin K2. When you combine this with Exercise/Nutrition/Recovery protocols, you will be well on your way to improving your health and well-being!
References
1. Kumar R. Vitamin D metabolism and mechanisms of calcium transport.J Am Soc Nephrol. 1990;1(1):30-42. doi:10.1681/ASN.V1130.
2. Van Ballegooijen AJ, Pilz S, Tomaschitz A, Grübler MR, Verheyen N. The synergistic interplay between vitamins D and K for bone and cardiovascular health: A narrative review.Int J Endocrinol. 2017;2017:1-12. doi:10.1155/2017/7454376.
3. Iwamoto J. Vitamin K₂ therapy for postmenopausal osteoporosis.Nutrients. 2014;6(5):1971-1980. doi:10.3390/nu6051971.
4. Sato T, Inaba N, Yamashita T. MK-7 and its effects on bone quality and strength.Nutrients. 2020;12(14):1-9. doi:10.3390/nu12040965.
5. Schwalfenberg GK. Vitamins K1 and K2: The emerging group of vitamins required for human health.J Nutr Metab. 2017;2017:1-6. doi:10.1155/2017/6254836.
6. Suziki Y, Okamato M. Production of hen’s eggs rich in vitamin K.Nutr Res. 1997;17(10):1607-1615. https://doi.org/10.1016/S0271-5317(97)00155-3.
7. English MM. The chemical composition of free-range and conventionally-farmed eggs available to Canadians in rural Nova Scotia.Peer J. 2021;9:1-16. doi:10.7717/peerj.11357.
8. Imbrescia K, Moszczynski Z. Vitamin K. StatPearls. Treasure Island, FL: StatPearls Publishing; 2025. https://www.ncbi.nlm.nih.gov/books/NBK551578/. Updated July 10, 2023. Accessed February 20, 2025.
-Michael McIsaac