Did you ever find an old shirt in your closet and think to yourself – “Why did I ever stop wearing this thing?”. Over the next few days and weeks, you find yourself wearing it much more frequently.
I get the same feeling about Vitamin K.
Vitamin K is a bit of a forgotten vitamin. Despite it’s important roles in blood clotting (and a concern for those taking blood thinning medications), I recently pulled it out from the back of the mental closet it’s now one of the vitamins I’m now most excited about.
Vitamin K is a fat-soluble nutrient that comes in a number of forms such as phylloquinone (K1) and menaquinone (K2). Each form of vitamin K is rather similar in its structure. The different forms of vitamin K affect how available they are to different body tissues -giving them overlapping, yet differing effects on the body.
The majority of Americans are vitamin K deficient, especially in the menaquinone variety which is found in foods such as natto (fermented soybeans) that are not eaten regularly in an American diet.
Vitamin K is known in textbooks to help in the blood clotting pathways in the liver. Much of the recommendations on vitamin K are based on levels needed for proper blood clotting – which may be insufficient for all of the other benefits of vitamin K (1).
We are just now starting to appreciate the wide metabolic effects of vitamin K2 on not just blood clotting, but bone health, cardiovascular health, neurological health, cancer development, energy production and more.
Age-related health declines tend to be most felt in cardiovascular, bone and brain health. A complete anti-aging discussion cannot be complete without including Vitamin K
Vitamin K2, and its variants like K2-7, also known as menaquinone-7 is involved in the activation (or “carboxylation” for nerdy types like me) of calcitonin and other vitamin K-dependent protein- notably something called matrix GLA protein which we’ll learn about in just a moment.
Vitamin K and Bone Health
Calcitonin bring calcium out of the blood and into the bone. I remember its function by repeating the saying: “Calcitonin helps to put the bone in”. Vitamin K activates calcitonin to help improve bone mineralization. It also keeps calcium from building up in places you don’t want it – the arteries.
As you increase the dose of Vitamin K2 above 100 ug, the activation of calcitonin increases proportionately (2). The increased action of calcitonin helps to increase bone health which is important for many Americans, most notably, the elderly, post-menopausal women, and other groups such as those with eating disorders.
When you think of bone health, the first thing that comes to mind is Calcium. There are some reports showing that extra calcium intake in the form of supplements may actually cause more harm than good (3). For an indepth discussion, I recommend reading The Calcium Paradox by Kate Rheume-Bleue which currently has 385 raving reviews on Amazon.
When I learned more about Vitamin K2, I realized that the story on calcium health is MUCH deeper than just focusing on calcium intake and Vitamin D. Once the calcium is absorbed properly from our food (and that absorption is enhanced with Vitamin D), it is Vitamin K that helps make sure that calcium ends up in the right place.
Vitamin K and the Prevention of Vitamin D Toxicity
Problems are created by over-supplementing with Vitamin D IF you are also deficient in Vitamin K2, particularly K2-7.
Most Americans are deficient in Vitamin D and will benefit from improving their Vitamin D levels to the 30-45 ng/mL range without a mention of Vitamin K. Many vitamin D supporters have demonstrated further benefits at levels up to 80ng/mL and more.
Although many doctors are comfortable supplementing with very high levels of vitamin D3. Concerns of vitamin D toxicity are still warranted.
While vitamin D has been known as a supervitamin for over a decade, we have learned that as vitamin D levels go above 40-45 ng/mL, that’s when vitamin K status becomes increasingly important to prevent Vitamin D toxicity. So if you’re going to take high doses of vitamin D, it’s likely very important that you ensure ample supply of Vitamin K too.
All of the fat soluble vitamins work in connection with one another. A discussion about Vitamin D and K is not complete without a mention of Vitamin A or Vitamin E. A full discussion of Vitamin A and Vitamin E is beyond the scope of this article.
Chris Masterjohn, PhD is a great resource for learning more about the dynamics of Vitamins A, D, E and K and fat metabolism. He has done a comprehensive job of covering these dynamics in all of its nerdy and scientific details.
Vitamin K2 and Heart Health
Vitamin K helps activate something called a Matrix GLA protein (MGA) which blocks calcium from depositing on arterial walls (3; 4). As we learned earlier, Vitamin K also activates calcitonin which takes calcium out of the blood and safely stores it in bone.
Calcium in the arteries is BAD – and accounts for probably the number one cause of death – cardiovascular disease. In short, vitamin K2 prevents calcium from building up in the arteries.
Under a microscope, arterial plaques can actually look a lot like calcium-rich bone scaffolding. Vitamin K may help stop or even reverse this process.
Without proper vitamin K status, you may literally start laying down bone in your arteries. The vessels stiffen and you increase your risk for atherosclerosis.
Cardiovascular health usually is linked closely to brain and kidney health which suggests enormous implications of ensuring adequate Vitamin K for healthy aging.
A 2015 study showed the K2 supplementation at 180ug per day over 3 years improved measures of arterial stiffness in post-menopausal women (5)
The VitaK-CAC study is a double-blind randomized controlled trial that is set to be completed in 2017. The hypothesis being studied is whether K2 supplementation will slow down or stop the progression of coronary artery calcification over a period of 1-2 years (6). When the media jumps on the results – you’ll know that you heard about Vitamin K here first!
Vitamin K’s ability to manage calcium could save the lives of MANY Americans – simply with its effects on calcium and cardiovascular health.
The benefits do not stop there.
Athletic Performance and Vitamin K2
Athletic performance may be improved with Vitamin D for instance, only when combined with vitamin K supplementation (7) . Many supplements focus on K2-4 which can be synthesized and made more cheaply than K2-7. K2-7 is better absorbed AND better at performing functions outside of the liver as it is able to be carried around in the blood for longer periods of time.
Because K2 has been associated with decreased arterial stiffness, it also increases cardiac output which allows the heart to pump blood more efficiently with each heartbeat. This may improve endurance – but generally is associated with better oxygen delivery to your brain and body.
If Vitamin K2 is confirmed to able to slow or reverse calcium deposits in the arteries, that will also physically clean the vessels out, improve blood flow, and reduce the risk of arterial tears and strokes.
Vitamin K2 and Inflammation
There is early work suggesting that Vitamin K can improve metabolic factors in Rheumatoid Arthritis (8; 9). Vitamin K also helps improve bone mineralization and generally may decrease arthritic and osteoporotic changes that may lead to inflammation.
Vitamin K2 and Cancer
A 2014 article in the Journal of Nutrition showed that Vitamin K1 and K2 intake levels were associated with decreased risk of cancer as well as cardiovascular disease and all-cause mortality (10). A protective role of vitamin K and prostate cancer tends to be the most well-supported association (11). The proposed anti-cancer mechanisms have been suggested by other researchers to be antioxidant and anti-inflammatory in nature, but also by helping to trigger programmed cell death (cancer cells learn how to stay alive longer than they should and vitamin K may stop this process) (12), and promoting the expression of healthy genes (13).
Vitamin K2 and Diabetes – Insulin Resistance
Diabetes often leads to inflammation of the blood vessel walls that can be followed by plaque formation – leading to cardiovascular disease, tissue injury, inadequate blood flow and more.
Vitamin K2 can also increase insulin sensitivity through its effects on calcitonin (14). The mechanism by how calcitonin imporves insulin resistance is not yet fully understood.
The hormonal effects of calcitonin are now understood as going well beyond just promoting healthy bones. K2-7 (menaquinone K2-7) is the best form of vitamin K to activate calcitonin.
Vitamin K2 and Kidney Health
Insulin resistance negatively affects the kidneys as excess sugar is flushed out of the body through the urine – causing damage to tissues along its path.
The first cause of death for those with kidney disease is actually cardiovascular mortality (15)
The kidneys filter the blood largely through specialized arteries. If calcification or stiffening develops in the arterial supply – kidney function can be altered. K2 may improve blood flow, decrease arterial calcification, and improve insulin resistance – thereby improving kidney health each step of the way.
Vitamin K2 and Brain Health
The brain is rich with blood flow – many neurodegenerative changes in the brain can be linked with altered blood flow and nutrient delivery, as well as waste removal.In addition to its pro-circulatory and anti-inflammatory benefits, vitamin K provides some functions that promote healthy membrane structure in the brain. It also may help protect the brain against oxidative stress (16). Cardiovascular disease can cause fatal strokes when clots, calcifications, or tears occur in the direct blood supply to the brain
Vitamin K2 and Healthy Energy Production:
Vitamin K2 is chemically known as menaQUINONE, which sounds a little like UbiQUINONE. We know ubiquinone as a form of Coenzyme Q10.
Bacteria produce K2 because it helps them produce energy like coenzyme Q10 does for us (17). It is possible that we use some of the components of menaquinone to help us produce coenzyme Q10 and therefore help boost antioxidant health and energy production at the cellular level.
At the very least, K2 may help absorb oxidative stressors as a capable electron carrier (18) which by itself is a powerful anti-aging mechanism.
Americans are largely deficient in vitamin K2 and as such are at higher risk for poor bone health and heart disease, independent of their calcium or cholesterol intake.
While it is likely most beneficial to consume a mix of K1, K2-4, K2-7, and some other versions of vitamin K. Vitamin K2-7 is the most bioavailable (19; 20), and is more capable of meeting needs outside of the liver, especially when it comes to the activation of calcitonin.
K2-7 is largely produced by Natto – which is largely nonexistent in American diets. K2-7 has a higher likelihood of being deficient than other forms. Other vitamin K types are found in dark leafy greens as well as fermented cheeses which tend to be more prevalent in American diets – whereas K2-7 largely needs to be consumed via Natto consumption or direct K2 supplementation.
K2-7 is now one of the super-vitamins I take myself and one that I am more actively recommending to my patients.
While there are many products available and you should find out which supplement is best for you and your circumstances (ESPECIALLY if you are on blood thinning medications or have a history of blood coagulation issues).
I personally use and recommend MegaQuinone K2-7.