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This article is the second of an ongoing series on fat-soluble vitamins, covering those that are integral to health and healing from chronic illness but often lacking in the modern diet. Check out my article on the importance of vitamin D, and Angie’s articles on vitamin A and vitamin E.
You have most likely heard more about the other fat-soluble vitamins, D, A, and E, but what about the lesser-known vitamin K? This nutrient flew onto my radar a few years ago when I started getting serious about healing my tooth decay that resulted from a decade of Veganism (more on that topic in another blog post!). I faced some early misconceptions about the K vitamins since I have a genetic blood clotting disorder that runs in my family — my grandmother can’t have any greens since she is on blood thinners, and would always lecture me about the clotting effects of Vitamin K. it wasn’t until I started looking into the specifics that I learned that there were two forms of vitamin K, each with different effects on coagulation, and K2 having many additional functions that I was unaware of. If you find yourself in the same boat, read on to find out more!
What is Vitamin K?
Vitamin K actually refers to a group fat-soluble vitamins, K1 and K2, found in leafy greens as well as animal products that are best known for their role in blood clotting. vitamin K1 is found in abundance in the diet in green leafy vegetables. Vitamin K2 is produced by bacteria as a byproduct of fermentation. Although K1 is easy to obtain in the diet, its absorption is low, around 10%, while K2 is much more difficult to obtain, but readily absorbed. It was only recently that the differences and functions of these two types of vitamin K became more understood.
What do vitamins K1 and K2 do in the body?
While most people are familiar with the role both vitamins K1 and K2 share in blood clotting (through the activation of coagulation factors in blood), not as many are aware that the important role K2 plays in cardiovascular health. Vitamin K2 also plays a role in depositing calcium in the correct locations throughout the body, like the bones, teeth, instead of the soft tissues. This article suggests that vitamin K2 has a role in cancer prevention (prostate) as well as skin and brain health, as well as suggests that the functions of K1 and K2 are so different that they be considered two separate vitamins entirely.
How does K2 promote cardiovascular, bone, and dental health? Its job is to make sure calcium gets to where it needs to go, and keep it out of the soft tissues like the kidneys and joints. An adequate source of K2 encourages the body to build strong bones and teeth.
What does deficiency look like?
Vitamin K1 deficiency causes symptoms associated with lack of blood clotting, like easy bruising, bloody nose, excessive bleeding, and heavy periods. Since vitamin K1 is so abundant in leafy green vegetables, most people don’t need to worry about becoming deficient or taking a supplement. Just eat your veggies!
Vitamin K2 deficiency causes the opposite of what we talked about in the previous section — weak bones, teeth, and calcification of the arteries, as well as other soft tissues. Not good, and unfortunately this type of deficiency is more common!
Just like vitamin D, vitamins K1 and K2 levels can be measured, although it is difficult to obtain an accurate result due to diet’s quick-acting effect on your levels. Results change rapidly one day to the next, making the results unreliable.
If you suffer from cardiovascular disease, osteoporosis, tooth decay, or calcification of soft tissues, it is safe to assume you should be better prioritizing your K2 intake, and talking to your doctor about supplementation.
How do you get vitamin K1 and K2?
Vitamin K1 is quite easy to obtain in the diet, especially for someone on the Autoimmune Protocol — it is found with abundance in leafy green vegetables like kale, chard, spinach, collard greens, parsley, broccoli, and brussels sprouts. You can pretty much bet that if it is a vibrant green color, there is going to be plenty of vitamin K1 contained within!
Vitamin K2, on the other hand, is a little more difficult to come by, especially on the elimination diet. Organ meats (especially liver) as well as fermented foods (meats as well as vegetables) are a good source of K2 while on the Autoimmune Protocol. It is found in lesser quantities in grass-fed or pastured meats. For those who have successfully reintroduced foods, both hard and soft cheeses, butter, and egg yolks can be good sources of K2.
While it was once thought that vitamin K2 was produced by our gut flora, recent research has shown that any K2 produced is not available to be absorbed by our bodies, making it necessary to obtain in the diet.
If I need to take a K2 supplement, which kind should I choose?
Since vitamin K2 is less abundant on the Autoimmune Protocol due to the exclusion of eggs and dairy in the diet, it might be wise to talk to your doctor about a K2 supplement if you are going to be on the elimination diet long-term, or if you suffer from related conditions (cardiovascular disease, osteoporosis, or tooth decay). While the Autoimmune Protocol is an incredibly nutrient-dense way of eating, I believe that those who do not tolerate reintroductions or have poor gut health should consider a high-quality supplement. I take this one because I do not tolerate dairy of any kind, and I do not eat eggs often. Look for a product that is carried in fat (as K2 is fat soluble) and free from additives or other ingredients.
It is important to note that anyone on blood thinning medication should speak to their doctor before changing their intake of vitamin K, either through diet or supplementation, as this can quickly change the effects of medication.