WARNING!
This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.
By Dr. Mercola
As I've discussed on numerous occasions, vitamin D is a critical nutrient for optimal health and is best obtained from sun exposure or a safe tanning bed.
However, many are taking oral vitamin D, which may become problematic unless you're also getting sufficient amounts of vitamin K2.
Vitamin K2 engages in a delicate dance with vitamin D, and you need both in adequate amounts for optimal health. The importance of this was once again highlighted in a new study…
Vitamin D and Vitamin K2 Slow the Progression of Arterial Calcification
The study was designed to compare the effect of oral administration of vitamin K2 (MK-7) plus vitamin D, or vitamin D alone, on the progression of coronary artery calcification score and carotid intima media thickness (the lining of the main arteries in your neck that feed blood to your brain), which are hallmarks of potentially lethal heart disease and stroke.
The data revealed a slower progression of calcification in those taking both vitamin K2 and vitamin D compared to those taking vitamin D alone.1 The study’s lead author said:
“In this study, the K2 and D protected against cardiovascular calcification, while the D group alone did not. Clearly, this has positive implications for human health."
This makes sense because whereas vitamin D provides improved bone development by helping you absorb calcium, there is new evidence that vitamin K2 directs the calcium to your skeleton, while preventing it from being deposited where you don't want it.
For example, in your organs, joint spaces and arteries. A large part of arterial plaque consists of calcium deposits (atherosclerosis), hence the term "hardening of the arteries."
Moreover, atherosclerosis can progress for many years, even decades, without symptoms, because the opening of the artery (lumen) formed by the arterial lining is still elastic enough to stretch to accommodate a degree of accumulated plaque.
That is, only if the artery has not begun to calcify, as the formation of a calcified fibrous cap on top of the arterial plaque deposit prevents further compensatory luminal expansion and therefore is the final, fatal step in the progression of the fatal disease.
We also know that vitamin K2 activates a protein hormone called osteocalcin, produced by osteoblasts, which is needed to bind calcium into the matrix of your bone. Osteocalcin also appears to help prevent calcium from depositing into your arteries.
In other words, without the help of vitamin K2, the calcium that your vitamin D so effectively lets in might be working AGAINST you -- by building up your coronary arteries rather than your bones.
Calcium and Vitamin D Without Vitamin K2 May Be Dangerous
If you take calcium and vitamin D but are deficient in vitamin K2, you could be worse off than if you were not taking those supplements at all, as demonstrated by one meta-analysis that linked calcium supplements to heart attacks.2
This meta-analysis looked at studies involving people taking calcium in isolation, without complementary nutrients like magnesium, vitamin D and vitamin K2, which help keep your body in balance.
In the absence of those other important cofactors, calcium CAN have adverse effects, such as building up in coronary arteries, initiating excessive clotting and causing heart attacks, which is really what this analysis detected. So if you are going to take calcium, you need to be sure you have balanced it out with vitamin D and vitamin K2.
Vitamin K2 and Matrix GLA Protein (MGP)
The authors of the featured study noted that, in addition to its role with osteocalcin, one of the mechanisms by which vitamin K2 exerts a protective role on the progression of vascular damage may be connected with its impact on Matrix GLA Protein, or MGP.3 MGP is the protein responsible for protecting your blood vessels from calcification.
When your body's soft tissues are damaged, they respond with an inflammatory process that can result in the deposition of calcium into the damaged tissue.
When this occurs in your blood vessels, you have the underlying mechanism of coronary artery disease -- the buildup of plaque -- that can lead you down the path to a heart attack.
Vitamin K2 and vitamin D again work together to increase MGP, which, in healthy arteries, congregates around the elastic fibers of your tunica media (arterial lining), guarding them against calcium crystal formation. According to Professor Cees Vermeer, one of the world’s top vitamin K2 researchers:
"The only mechanism for arteries to protect themselves from calcification is via the vitamin K-dependent protein MGP. MPG is the most powerful inhibitor of soft tissue calcification presently known, but non-supplemented healthy adults are insufficient in vitamin K to a level that 30 percent of their MGP is synthesized in an inactive form.
So, protection against cardiovascular calcification is only 70 percent in the young, healthy population, and this figure decreases at increasing age."
Vitamin K2 as MK-7: What You Should Know
There are several different forms of vitamin K2. MK-8 and MK-9 come primarily from fermented dairy products, like cheese. MK-4 and MK-7 are the two most significant forms of K2 and act very differently in your body.
MK-7, which is the form used in the featured study, is a newer agent with more practical applications because it stays in your body longer; its half-life is three days, meaning you have a much better chance of building up a consistent blood level, compared to MK-4 or vitamin K1.
MK-7 is extracted from the Japanese fermented soy product called natto, and you can obtain all the K2 you’ll need (about 200 micrograms) by eating 15 grams of natto daily, which is half an ounce.
However, natto is generally not appealing to a Westerner’s palate, so you can also find vitamin K2, including MK-7, in other fermented foods, including fermented vegetables made with the proper starter culture (a starter culture of vitamin K2-producing bacteria). Gouda and Brie cheeses each contain about 75 mcg of vitamin K2 per ounce, while scientists have found high levels of MK-7 in a type of cheese called Edam.
Dr. Kate Rheaume-Bleue, a naturopathic physician, estimates that about 80 percent of Americans do not get enough vitamin K2 in their diet to activate their K2 proteins to shuttle the calcium where it needs to be and remove it from the places where it shouldn't be.
The next best thing to dietary vitamin K2 is a vitamin K2 supplement. MK-7 is the form you'll want to look for in supplements, because in a supplement form the MK-4 products are actually synthetic. Although the exact dosing is yet to be determined,
Dr. Vermeer recommends between 45 mcg and 185 mcg daily for adults. You must use caution on the higher doses if you take anticoagulants, but if you are generally healthy and not on these types of medications, I suggest 150 mcg daily.
Remember: If You Take Oral Vitamin D, You Need Vitamin K2
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If you remember only one thing from this article, make it this: if you opt for oral vitamin D, you need to also consume in your food or take supplemental vitamin K2. Dr. Rheaume-Bleue warns:
"There are so many people on the vitamin-D-mega-dose bandwagon, taking more and more of vitamin D. And it could absolutely be causing harm if you are lacking the K2 to complete the job to get the calcium where it's supposed to be. We don't see symptoms of vitamin D toxicity very often. But when we do, those symptoms are inappropriate calcification. That's the symptom of vitamin D toxicity. And it is actually a lack of vitamin K2 that can cause that..."