Vitamin K: What is it and what is its function?
There are so many vitamins and minerals out there—how can you possibly know what’s what? Some nutrients get a lot of attention (we’re looking at you, vitamin D and vitamin C), and there are others that deserve a little more attention than they get. When it comes to heart health specifically, there are a few nutrients that are particularly important, including magnesium, CoQ10, fish oil, and even carnitine. But have you ever heard of vitamin K2? Often overlooked, this may be the top nutrient for heart health.
Vitamin K benefits
Vitamin K is one of the four fat-soluble vitamins: A, E, D, and K. You may be aware that vitamin K guides calcium safely into the bones to strengthen bone mineral density and reduce fractures, but beyond that, it also prevents calcium from accumulating in our vessels and can even remove dangerous calcifications.
So how does this relate to heart disease? If you’ve ever heard of a coronary calcification score, this test checks for calcium buildup in your coronary (heart) arteries. A high score means you’re at high risk of heart disease. Getting the proper amount of vitamin K means you’ll be doing your part in preventing dangerous calcium plaque buildup.
Vitamin K and heart health
Whether your cholesterol is high or low, what really matters is whether calcium plaque is building up in your arteries, leading to potentially fatal blockages. Vitamin K helps direct calcium to the correct and beneficial places for your health, keeping it away from the wrong places that can be detrimental to your health, like the arteries.
How does vitamin K accomplish this? It activates important proteins like matrix GLA protein (MGP). This is where the magic happens, as this protein keeps your calcium from depositing into blood vessels and other soft tissues. In fact, the Rotterdam Study published in the Journal of Nutrition in 2004 showed that individuals with the highest dietary intake of K2 will live on average seven years longer than K2-deficient individuals. Why? Because it reduces the incidence of arterial calcification.
K and K2: The different types of vitamin K
Vitamin K is broken into K1 and K2. Vitamin K1 is known as phylloquinine, and K2 is known as menaquinone. K1 deficiency is actually very rare because you’ll find it in leafy greens like kale, collards, spinach, turnip greens, beet greens, broccoli, and Brussels sprouts. As long as you’re getting greens in your diet regularly, this type of K deficiency is not something to worry about. Vitamin K2, on the other hand, comes from very specific foods and bacterial synthesis. Because of that, many individuals are deficient in K2 and don’t even realise it.
It was previously believed that we didn’t need to supplement K2 because our gut bacteria was able to make it for us. However, the amount produced in your gut varies from person to person. You must have enough healthy bacteria for this process to happen. However, if you have taken antibiotics or have suffered from gut infections and food sensitivities, you may not have ample K2 production in the gut. K2 is not stored in the body, so we need to consume it regularly through the right foods or supplementation.
Foods containing vitamin K2
Vitamin K2 is found in fermented soybeans, as well as the fat, milk, and organs, of grass-fed animals. This includes egg yolk, butter, and even liver. Much of our livestock is no longer grass-fed, which reduces the K2 concentration in foods they produce. When we removed animals from the pasture, we inadvertently removed K2 from our diets. Why, you ask? Chlorophyll is the pigment that makes green plants green, and when cows, for instance, consume these green plants, they are ingesting K1, which is then converted to K2. Only the grass-fed animals have likely converted K1 to K2 for us. This is another example of what makes Michael Pollan’s famous statement, “You are what what you eat eats.” So, so true. Wild game like pheasant, duck, rabbit, venison, elk, boar, and wild turkey eat more green vegetation, which can increase the K2 you get from foods they produce as well.
Heart disease is known as the silent killer, so you may not necessarily experience classic symptoms of a “K2 deficiency.” However, what we know is that many cancers, osteoporosis, infertility, varicose veins, diabetes, wrinkles, dental cavities, Crohn’s disease, heart disease, and kidney stones are associated with a deficiency in K2.
Vitamin K and vitamin D
You may be wondering where vitamin D fits in—and why you sometimes see vitamin K2 in vitamin D supplements. Vitamin D increases the absorption of calcium from the intestines, but unfortunately, once it makes it into our bloodstream, vitamin D has no control over where calcium goes. Although some will end up in the bones, some may also end up in the arteries. Think of vitamin D as the doorman opening the door for calcium to enter the bloodstream. Vitamin K is the usher that takes calcium from the lobby and directs it to its appropriate seat in the bone matrix. K2 helps bind calcium to the bone and synergistically works with vitamin D3 to improve calcium absorption. Taking vitamin D increases the body’s need for vitamin K2 as well. That means if you supplement with vitamin D, your body likely needs K2 as well.
Vitamin K2 supplements and dosing
There are two major categories of K2 supplements, MK4 and MK7. MK4 is typically extracted from the tobacco plant. Its downside is that is has a very short half-life, meaning it doesn’t stay in the body very long (really only a few hours at a time). MK7 is typically sourced from natto (fermented soybeans), geranium, or chickpea. It has a longer half-life, so a single daily dose can provide longer protection. The effective studied dose is at least 90 mcg/day, and many studies will tell you 180 mcg. MK7 at this dose shouldn’t significantly interfere with the blood-thinning benefits of drugs when taken at a similar dose. However, always alert your medical provider to all supplements and medications you are taking, and they can monitor this effect.
If your mind is reeling after reading this, let me break down the key take-aways: Getting enough K2 in your diet all boils down to having proper gut health, eating the K2-rich foods I’ve listed above, and taking K2 supplements—preferably from MK7. Having the right amount of K2 is not only beneficial for your bone health but protects your vessels and your heart. Remember, K2 is essentially the usher that directs calcium to all the right places while avoiding the wrongplaces like our arteries.