What is vitamin K?
Vitamin K is a fat soluble vitamin best known for its role in blood coagulation. The biological forms of this vitamin include K1 (aka phylloquinone) and Vit K2 (aka the menaquinones). Menaquinones are a family of molecules with the abbreviation MK-n (M=Menaquinone, K=Vitamin K, and n=the particular subtype).
Vitamin K1 is found copiously in green leafy vegetables, due to its role in photosynsynthesis. It is the plant form of vitamin K, but also has biological activity in humans and other animals. Vitamin K1 in animals can also be converted to K2.
Vitamin K2 is the main storage form of vitamin K in animals. The most common subtype of vitamin K2 in the body is MK-4. MK-4 is produced in many tissues in the body (i.e. arterial wall, testes, liver, pancreas, etc) from the conversion of K1 to K2. The other menquinones (especially MK-7 through MK-11) are converted from K1 in the gastro-intestinal tract by gut bacteria. MK-4 and -7 are the most studied subtypes of vitamin K2.
Foods with high amounts of vitamin K2 include: natto (a type of fermented soy), cheese, egg yolks, chicken liver and pate.
There are also synthetic forms of vitamin K (K3 through K5). K3 does have potential toxicity whereas K4 and K5 do not. Most vitamin K supplements contain only the biological forms K1 and K2, and considered very safe. In fact, no known toxcity is found with either K1 or K2.
By the way, this vitamin gets its “K” designation from the German word, Koagulation, where it was first discussed in a German journal as a Koagulation vitamin by its Nobel Prize discoverer, Henrik Dam.
Why is Vitamin K important?
Vitamin K is typically known as a vitamin that assists with blood clotting. However, this vitamin has many more uses in the body then most people realize. Knowing this is important because depending on health status, Vitamin K sufficiency can be a life-saver.
Vitamin K’s best friend in the body is the mineral calcium. It uses calcium to cause a biological effect. Basically, Vitamin K modifies proteins so that they can bind calcium. After this mineral binds, these proteins do various jobs like: reinforce the blood clotting cascade, strengthen bones, prevent vascular calcification, and even reduce cancer risks.
Which conditions and diseases can Vitamin K use effect?
In general, most people make and consume sufficient quantities of vitamin K. There are certain conditions and circumstances, in regard to bone health, that may warrant extra vitamin K.
excessive corticosteroid use
Parkinson’s disease, and others.
It is no secret that corticosteroid use has devastating effects on bone health. Research shows that supplementing with vitamin K mitigates the bone ravaging effects of steroids. Vitamin K’s bone sparing results also positively effect Anorexia and Bulimia Nervosa, two conditions known to weaken bones and have other harmful effects on the body.
People suffering from diseases that compromise liver function may also have need for extra vitamin K. Increased fracture risk with osteoporosis and osteopenia is blunted with extra vitamin K. It is probably fair to say, that any condition involving limited use of skeletal muscles like: disuse from stroke, paralysis, multiple sclerosis, or even a sedentary lifestyle, will benefit with extra vitamin K. People with Alzheimer’s and Parkinson’s disease may also alleviate bone loss with extra vitamin K.
Extra Vitamin K?
People on the blood thinning drug, warfarin aka Coumadin, are usually aware that consuming extra vitamin K, either through supplementation or diet, may put them at risk of clotting. This medication works by creating a deficiency of vitamin K in the body, thus keeping your blood thin. Unfortunately, there is evidence, in animal studies, that long-term use of Coumadin can enhance calcium deposition in the arteries. The good news is, these studies prove regular Vitamin K supplementation reverses this condition. Most doctors are no longer recommending a “white foods” diet in order to keep bleeding times stable. Thus allowing one to eat healthy greens, as long as they are consistent with the amounts on a daily basis. By doing this your healthcare provider can adjust the dose of Coumadin based on your dietary intake of vitamin K.
People on long-term antibiotics may also have an increased need for vitamin K, due the devastating effects these medications have on gut bacteria. Without gut bacteria, vitamin K1 cannot convert to vitamin K2, possibly causing a deficiency. Furthermore, it is likely that any medication or disease that compromises digestion can elicit a need for more vitamin K. This includes Celiac disease, Irritable Bowel Syndrome (IBS), Ulcerative colitis, etc.
Other things that put people at risk for vitamin K deficiency are the following:
- diets low in vegetables and fruit,
- begin elderly due to less efficient conversion K1 to K2,
- chronic kidney disease,
- and having the apoE4 genotype.
Having the apoE4 genotype is highly correlated with Alzheimer’s disease. Carriers of this genotype also have lower levels vitamin K. Research indicates that vitamin K plays a role in preventing nerve damage. As such vitamin K supplementation may help stave off this diseases of dementia, like Alzheimer’s, especially in apoE4 carriers.
The research on vitamin K in regards to cancer seems to connote a powerful anticancer effect. Vitamin K2 proves to be protective against liver cancer through numerous biological mechanisms. Studies show many types of cancers are suppressed, or prevented, by vitamin K2 including: lung, bladder, colorectal, stomach, bile-duct, prostate, non-hodgkin lymphoma and brain cancers. The anti-cancer effects of vitamin K2 occur in a variety of ways throughout all stages of cancer including preventing it in the first place.
Studies show that Vitamin K prevents vascular calcification thus, reducing the risk of atherosclerosis. This makes sense since one of the main jobs of vitamin K in the body is to help direct calcium to the bone, thus preventing it from depositing in vascular tissues. This anti-calcification effect can reduced the risk of myocardial infarction, aortic aneurysms, high blood pressure, and numerous other problems associated with cardiovascular disease (CVD). Evidence shows a strong inverse association between vitamin K2 intake and the risk of developing coronary heart disease. The higher your intake of K2 the lower your risk of coronary heart disease. Another disease strongly associated with CVD, diabetes, and sufferer’s experience benefits with vitamin K intake, specifically K1.
As implied above, maintaining healthy bones requires vitamin K. Vitamin K2, specifically the MK-7 subtype, has been show to stimulate osteoblasts (your bone-building cells) while blunting activity of osteoclasts (your bone-degrading cells) thus helping make bones stronger. MK-4 subtype also has also been show to prevent bone loss in certain situations as stated above. The Ministry of Health in Japan since 1995 has gone so far as recommending MK-4 in the prevention and treatment of osteoporosis. Unfortunately, the conventional medical consensus of using vitamin K for improving bone health as not yet caught up with Japan.
To be fair, there is not copious amounts of evidence to support this; however, taking extra vitamin K for bone health cannot hurt, and probably will help based on the accumulated data. Vitamin K certainly does appear to prevent fractures. Here in the US, vitamin K primarily functions as medicine, to help with blood coagulation in newborns, and as an antidote for over-dosing of 4-hydroxycoumarin, found in Coumadin and certain rat poisons.
It appears that vitamins K1 and K2 have, both, similar and different roles in the body; therefore, both forms should be taken. High quality bone health supplements will usually contain both biological forms, K1 and K2. There are no findings of toxicity with high intake of vitamin K1 and K2. This dispels the myth, that someone not taking Coumadin, and taking high amounts of vitamin K will increase their blood clotting risk.
The research on vitamin K show it affecting the body in numerous beneficial ways. Its safety profile and accumulated evidence warrant its use in many types of conditions and diseases. In fact, its celebrity status should be on par with vitamin D, and both should be taken together since they are partners in helping maintain healthy bones. I am certain that in the future we will find them partnering along with the other fat soluble vitamins E and A in the fight against cancer, osteoporosis and dementia.
In my opinion, based on the current evidence, Vitamin K1 and K2 should definitely be part of osteoporosis prevention and treatment protocol, and be ingredients in any bone building supplement. Furthermore, for people not worried about bone health, there is sound reason to consume vitamin K everyday, either by eating plenty of greens and other vitamin K foods or by supplementing with it.