Most information about vitamin K2 and arterial disease focuses on calcification. The assumption is that K2 moves calcium from arteries into bone, a process that may affect stable plaques. But there may be different mechanisms on how vitamin K2 really works.
The discovery of vitamin K
In 1935, Danish biochemist Carl Peter Henrik Dam described a food additive that reduced blood clotting in chicks fed with an extremely low-fat diet. He named it “vitamin K,” after the first letter for the Danish and German word for coagulation (Shampo, 1998).
A few years later, American biochemist Edward Adelbert Doisy determined vitamin K’s chemical structure and succeeded in synthesizing it. For their work on vitamin K, Dam and Doisy shared a 1943 Nobel Prize in Physiology or Medicine.
Vitamin K1 vs. K2
Vitamin K has since been shown to have 2 forms—vitamin K1 and K2—each with very different contributions to human health.
Vitamin K1 (phylloquinone) was the one discovered by Dam and Doisy. Green, leafy vegetables are rich in this vitamin. It’s the form that’s primarily involved with coagulation.
Vitamin K2 (menaquinone) is sourced from meat, eggs, cheese, and a Japanese food called natto. It has subtypes, from MK4 to MK13. The subtypes differ in chain lengths.
Vitamin K2 was overlooked until it was “rediscovered” to be an important factor in bone and cardiovascular (CV) health. But the prevailing notion is that vitamin K2 reverses coronary artery calcification, which may affect stable, calcified plaques.
That notion creates confusion, and people don’t know if taking vitamin K2 is fine. That’s why vitamin K2 remains a popular topic (although a controversial one) in CV health discussions.
Vitamin K2 and calcification
We know that calcium is important for maintaining healthy bones. But simply adding calcium to the diet does not ensure that calcium will even make into the bones, much less stay there. Other things are required, like hormones and vitamins. This is where vitamin K2 comes in.
Osteoblasts and osteoclasts
In terms of bone health, the first vitamin we usually think of is vitamin D. But there are multiple animal studies showing vitamin K2 suppressing bone loss. How?
First, vitamin K2 acts on osteoblasts and osteoclasts (Myneni, 2017). Vitamin K2 increases the activity of osteoblasts. (Osteoblasts are cells which build up bones.) Vitamin K2 also inhibits osteoclasts. (Osteoclasts are cells that break down bones by removing calcium.)
Osteocalcin and matrix Gla protein
Does vitamin k2 remove calcium deposits from arteries? It appears to do so, and it has something to do with osteocalcin and matrix Gla protein.
Osteocalcin is a protein produced by osteoblasts, with important roles in bone mineralization and calcium homeostasis. It is activated by a carboxylation, a reaction in which vitamin K2 is the essential cofactor. Once activated, osteocalcin binds calcium in the bloodstream for transport into the bone matrix.
Vitamin K2 also activates matrix Gla protein (or MGP) through carboxylation. MGP is another protein that ensures that calcium is used in bones and not deposited in arteries and other tissues.
If you like a deeper look into vitamin K2, MGP, and osteocalcin, check out our other article on vitamin K2.
Vitamin K2, prediabetes, & diabetes
Most of the information you see about vitamin K2 and arterial disease focuses on calcification, as we discussed in the previous sections. Again, there could be a different mechanism, something that involves prediabetes, insulin resistance, and diabetes.
Scientists have noticed that vitamin K2 supplementation prevents the onset of prediabetes or diabetes. One of them is Dr. Joline Buelens, Professor of Lifestyle and Cardiometabolic Disease Epidemiology at the Amsterdam Public Health program. Her research is focused on nutrition, cardiovascular health, and diabetes. She has been involved in several studies demonstrating the preventive impact of vitamin K2 on diabetes (Beulens, 2010).
The work on the association between vitamin K2 and prediabetes or diabetes is still not completely proven. But apart from Beulens’ studies, several meta-analyses support vitamin K2’s effect in this area.
Here’s one good article. It’s titled “Effect of vitamin K2 on type 2 diabetes mellitus: A review” (Li, 2017). Some of the points highlighted in this review are:
- Vitamin K2 has a more significant impact on diabetes than vitamin K1.
- Taking vitamin K2 lowers the risk of type 2 diabetes by 7% per 10 mcg increment.
- Vitamin K2 improves insulin sensitivity through osteocalcin, anti-inflammatory properties, and lipid-lowering effects.
There are aspects of vitamin K2 and plaque removal that we haven’t completely understood yet. But we now know that it plays a role in the calcification/decalcification of arteries and bones. It affects certain cells (osteoblasts and osteoclasts) and proteins (osteocalcin and MGP). More importantly, we also know now that vitamin K2 has a great impact on insulin resistance and diabetes.
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Beulens JW, van der A DL, Grobbee DE, Sluijs I, Spijkerman AM, van der Schouw YT. Dietary phylloquinone and menaquinones intakes and risk of type 2 diabetes. Diabetes Care. 2010;33(8):1699-1705. doi:10.2337/dc09-2302
Li Y, Chen JP, Duan L, Li S. Effect of vitamin K2 on type 2 diabetes mellitus: A review. Diabetes Res Clin Pract. 2018;136:39-51. doi:10.1016/j.diabres.2017.11.020
Myneni VD, Mezey E. Regulation of bone remodeling by vitamin K2. Oral Dis. 2017;23(8):1021-1028. doi:10.1111/odi.12624
PrevMed. What is Vitamin K2? Can It Remove Arterial Plaque? PrevMed website. Accessed September 9, 2020. https://prevmedhealth.com/vitamin-k2-can-it-remove-plaque/
Shampo MA, Kyle RA. Henrik Dam–Discoverer of Vitamin K. Mayo Clin Proc. 1998;73(1):46. doi:10.1016/s0025-6196(11)63617-3
Turck D, Bresson JL, Burlingame B et al. (2017). EFSA Journal. Dietary reference values for vitamin K. 2017;15(5). doi:10.2903/j.efsa.2017.4780