Vitamin D has been getting a ton of press for the last decade. It seems like every study is touting its benefits. As with many natural medicines, vitamin D is certainly a “cure-all” especially when one is deficient. Unfortunately, most of are deficient or at the lower end of normal on a blood lab. In all my years of practicing medicine, it seems I have only seen a hand full of people that have had optimal vitamin D levels. Many doctors, including myself, are now recommending testing and vitamin D to almost everyone. I think this is good medicine with what we know thus far about vitamin D. However, the biggest problem I see is that doctors are only recommending vit D without vit K or any of the other fat soluble vitamins. Taking vitamin D with calcium and without vitamin K has the potential to create health problems.
Firstly, I feel it is important that one should always take vitamin K when supplementing with vitamin D. The only possible exception to not taking vitamin K with vitamin D is when someone is on blood thinners. Vitamin K helps with blood coagulation so it may offset the blood thinning effects of medicines like warfarin or coumadin. Not taking vitamin K or not eating your greens (green leafies contain vit K) while on a blood thinner is another blog on to itself; as you can probably tell from my tone there is some controversy on this subject. Anyway, assuming one is not on a blood thinner, one should always supplement with vit K and even the other fat soluble vitamins like vit E and A.
Why would this be? What is so important about vit K in relation to vit D and calcium?
First of all there are a few different forms of vit K (Vit K1, Vit K2, and Vit K3) and each does something a little different for your body. Believe it or not, there are actually 14 subtypes of Vit K2, two of the most important for bone are Vit K2 (MK-4) and (MK-7).
Vit K1 – is the naturally occurring vit K found in vegetables. In regards to bone it helps to direct calcium to bone. It has many other uses in the body, the most well-known is helping with coagulation.
Vit K2 (MK-4) and (MK-7) – is the most bio-available form of vit K. It is considered by many to be the most active form of vit K in the body. This form of vit K is converted from vit K1 by your gut bacteria and your cells. Vit K2 (MK-7) is found mostly in fermented foods like cheese, natto, sauerkraut, and kimchi. Taking antibiotics or just being a poor a converter of vit K1 can decrease the amount of vit K2 you get.
Vit K3 - Is produced from both vit K1 and vit K2 in the intestinal wall. It is not found in any foods in significant amount.
So how does vit K work in helping build strong bones? In bone there is a very important protein called osteocalcin. Osteocalcin is actually produced by your bone building cells called osteoblasts. Osteocalcin helps to direct calcium to the hydroxyappatite structure of bone, thus support mineralization of bone. In other words, osteocalcin takes calcium in the body and puts it in bone where it belongs. Vit K causes bone to increase it’s production of osteocalcin and collagen. Collagen is another protein that helps to give elasticity to bone. So vit K boost bone collagen too.
Vit K Þ Osteocalcin and collagen Þ calcium in bone Þ stronger and denser bones
Think goodness for vitamin K helping to direct calcium to the bone. Without it calcium would deposit in the soft tissues of the body like arteries, vein, and skin; and this is not a good thing. Because if you think about it you realize that osteoblasts, the cells the produce osteocalcin, reside in the bone. What if the calcium is floating around somewhere else other than beside the bone where osteocalcin cannot grab it and utilize it to build bone? What is preventing the calcium from depositing in the soft tissues instead?
Well there is another vitamin K dependent protein called Matrix Gla protein (MGP) that is found in the soft tissues of the body. It’s main function is to keep calcium from depositing in the soft tissues. Cardiovascular problems like hardening of the arteries is in part due to MGP not having vitamin K to optimize it function. MGP, like osteocalcin, requires vitamin K to do it’s job of keeping the soft tissues soft.
So how do the other other fat soluble vitamins (A and E) help out. Without going into too much detail just know that for vit K and vit D to do a good job, both vitamins A and E should be hanging out with them too.
There is some overlap with the physiological roles of vit K and D; however the easiest way to remember their roles in relationship to bone health is the following:
Vit D helps take calcium from the gut to blood and Vit K helps to direct calcium away from soft tissues while directing it to the bone.
So what is the message here? Take your vit D with vit K especially when you are supplementing with calcium too. Oh yes, please talk with your doctor about supplementing with vit K if you are on a blood thinner.
Keoni Teta