Vitamin K was discovered in 1929, according to Wedman-St Louis (2015), “and named for the German word koagulation, with Henrik Dam and Edward A. Doisy receiving the Nobel Prize for their research in 1943. But vitamin K is a multifunctional nutrient.
“Vitamin K-1, or phylloquinone, is found in green leafy vegetables and used by the liver for blood coagulation in 10 hours.
“Vitamin K-2, also known as MK-7 or menaquinone, comes from natto (fermented soybeans), organ meats, egg yolks and raw milk cheeses. It circulates throughout the body over a 24-hour period.”
Rotterdam Study
The Rotterdam Study in the 2004 Journal of Nutrition focused on the role of K-2 as an inhibitor of calcification in the arteries and the major contributor to bone-rebuilding osteocalcin. The study reported that K-2 resulted in a 50 percent reduction in arterial calcification, a 50 percent reduction in cardiovascular deaths and a 25 percent reduction in all causes of mortality. K-1 had no effect on cardiovascular health (Wedman-St Louis, 2015).
In fact, Rotterdam Study findings suggest a protective effect of menaquinone (Vitamin K-2) intake against chronic heart disease congenital heart defect coronary heart disease (CHD), which could be mediated by inhibition of arterial calcification. Adequate intake of foods rich in menaquinones, such as curds and (low-fat) cheese, may contribute to CHD prevention (Geleijnse et al., 2004).
Multiple Forms
Vitamin K-2 is not a single vitamin, but rather is a form of vitamin K itself, which is composed of a number of different forms. Vitamin K-1, for example, is found primarily in leafy green vegetables and its main function is in the production of blood clotting proteins. All are considered to be fat-soluble vitamins and are required by the body for a number of different biochemical reactions including blood clotting, calcium balance, energy production and the creation of powerful antioxidants. Vitamin K-2 can be made from vitamin K-1 by many different organs in the body. It is also made in several different forms by the bacteria in the bowel (Massey, 2017).
Vitamin K-3 is no
longer used to treat vitamin K deficiency because of associated
toxicities (Massey, 2017).
Also, there are many different forms of vitamin K-2. The best food sources of Vitamin K-2 are grass-fed dairy products, emu oil, gouda and brie cheese, and natto, a very strong tasting fermented soy product with roots in Japan. Vitamin K-2 from animal sources is known as MK-4, while Vitamin K-2 from natto, produced by bacterial fermentation, is known as MK-7. Vitamin K-2 from animal sources is known as MK-4 while Vitamin K-2 produced by bacterial fermentation as found in natto is known as MK-7 (Pope, 2017). Of the two forms, MK-7 is preferred. It lasts longer in the body and has a greater physiological effect (Wiggy, 2016).
Calcium Regulation
It is well documented, according to Pizzorno (2008), “that vitamin K-2 (menaquinone) is the essential cofactor for the carboxylation (activation) of the (gamma-carboxyglutamic acid) Gla-containing proteins involved in calcium regulation.”
Numerous peer-reviewed studies have shown that vitamin K-2 — given either as the (vitamin store) synthetic form MK-4 (a short-chain version called menatetrenone) at a dosage of 45 mg/day, or as the natural form, MK-7 (a long-chain menaquinone derived from natto) at a dosage of 45 mcg/day — is a highly effective activator of osteocalcin, the Gla-containing protein integral to calcium deposition in bone. This body of research conclusively demonstrates that vitamin K2 not only lessens fracture incidence and improves bone density but also, via the carboxylation of another Gla protein (matrix Gla protein), inhibits arterial calcification (Pizzorno, 2008).
Statins and Heart Health
Interestingly, a recent study suggests that statin medication use, instead of reducing the risk of coronary heart disease, may indirectly increase it. The reason is because of the interactions of statins with various metabolic pathways involving vitamin K-2. This is important because low levels of vitamin K-2 are associated with an increased risk of not only severe coronary artery disease (CAD) but also type II diabetes and mortality (Massey, 2017).
Statin-induced suppression of prenyl intermediates in the cholesterol biosynthetic pathway has been linked to stimulated atherosclerosis and heart failure. On the other hand, certain types of vegetable oil and hydrogenated oil shortened the survival of stroke-prone spontaneously hypertensive rats by decreasing platelet number, increasing hemorrhagic tendency and damaging kidney functions, which could not be accounted for by their fatty acid and phytosterol compositions. These vegetable oils and medicines such as statin and warfarin share, in part, a common mechanism to inhibit vitamin K2-dependent processes, which was interpreted to lead to increased onset of CVD, DM, chronic kidney disease, bone fracture and even mental disorder (Okuyama, et al., 2016).
The article was published in the medical journal Pharmacology in 2016, Massey (2017) said. “A large group of researchers from several universities in Japan explained that many of the mechanisms associated with the prevention of coronary artery disease (CAD) are vitamin K-2 dependent. That means that low a level of vitamin K-2 may increase the risk of severe coronary artery disease.
“They also discussed the fact that statin medications inhibit the production of vitamin K-2. It is well-known that statin medications reduce the production of a very specific compound called coenzyme Q 10. However they also reduce the production of other coenzyme Q 10 look-a-like compounds that are essential for vitamin K-2 to reduce the risk of severe CAD.”
In addition, statin medications directly inhibit the conversion of vitamin K-1 to vitamin K-2. The end result is a significant increase in the risk of both the development and severity of CAD (Massey, 2017).
Refined Oils
The vegetable oils, found at most grocery stores, should also be mentioned. They are clear, tasteless, highly refined and processed oils — most commonly sunflower, soybean, canola, safflower and corn oils (Landers, 2016). Olive oil is the best oil to use, but this has not been confirmed. (The original study has yet to be read in its entirety.)
Best Source of Vitamin K-2
According to Day (2017), “the very best way to prevent a vitamin K-2 deficiency, is to eat a large serving of green leafy vegetables every day. Green leafy vegetables are sky high in vitamin K-1. Your body will then convert vitamin K-1 to vitamin K-2.
“Fermented foods, like fermented soybeans, sauerkraut, and some cheeses, such as brie or gouda, can all be good sources of vitamin K-2. Even though yogurt and kefir are also fermented foods, the grocery store variety contains the wrong bacteria for vitamin K-2.
“Other good sources of vitamin K-2 include liver and grass fed chicken eggs. Of all these sources, nothing even comes close to the amount of vitamin K-2 found in natto or fermented soybeans. Indeed, one serving of natto has enough vitamin K-2 for an entire week. Not only is natto loaded with vitamin K-2, but this fermented food may also help your gut flora.”
Natto is a delicacy in Japan. Unfortunately, most Westerners cannot tolerate the taste (Day, 2017).
Caution
Very high doses of vitamin K-2 have proved remarkably safe in large clinical trials, according to Masterjohn (2016), “but there are safety concerns for people taking prescription anticoagulants, and there are reasons to be cautious about high doses even for healthy people.
“As a class, these drugs act as vitamin K antagonists, and it is
absolutely critical that anyone taking them avoid making any changes
to their diet or supplements that would be expected to change their
vitamin K intake except under the strict supervision of the physician
who prescribed the medication.”
Smaller Dose Ideal
Long-term use of 45 mg per day of MK-4 has not revealed any established toxicity syndrome or risk of serious side effects. This is 225 times the dose I recommend (this is a recommendation of 200 mcg, or 20 percent of 1 mg). Nevertheless, the biochemistry of vitamin K suggests that unnecessarily high doses could rob the body of antioxidants or interfere with blood sugar regulation, insulin sensitivity, and hormonal health (Masterjohn, 2016).
References
Day, J. (2017). Nine signs you may have vitamin k-2 deficiency.
The Longevity Plan. Retrieved July 11, 2017 from
http://drjohnday.com/9-signs-you-may-have-vitamin-k2-deficiency/
Geleijnse, J.M., et al. (2004).
Dietary intake of menaquinone is associated with a reduced risk of
coronary heart disease: the rotterdam study. The Journal of
Nutrition. Retrieved July 11, 2017 from http://jn.nutrition.org/content/134/11/3100.full.pdf
Massey, P. (2017, May 22). Vitamin K plays a role when taking
statin medications. Chicago Daily Herald, p. 0.
Masterjohn, C. (2016, December 9). The Ultimate Vitamin
K-2Resource. Chris Masterjohn PhD. Retrieved July, 12, 2017 from https://chrismasterjohnphd.com/2016/12/09/the-ultimate-vitamin-k2-resource/
Okuyama, H., et al. (2016, June 2). Medicines and vegetable oils
as hidden causes of cardiovascular disease and diabetes.
Pharmacology, 98(3-4), 134-70. (Abstract). Retrieved July
11, 2017 from https://www.ncbi.nlm.nih.gov/pubmed/27251151
Pizzorno, J. (2008, October 27). Vitamin k2, but not vitamin k1,
is helpful for bone density. WebMD. Retrieved July 11, 2017
from http://blogs.webmd.com/integrative-medicine-wellness/2008/10/vitamin-k2-but-not-vitamin-k1-is-helpful-for-bone-density.html
Pope, S. (2017). Which Vitamin K2 Supplement is Best: MK-4 or
MK-7? The Healthy Home Economist.
Retrieved July 11, 2017 from http://www.thehealthyhomeeconomist.com/which-vitamin-k2-supplement-is-best-mk-4-or-mk-7/
Wedman-St Louis, B. (2015, October 15). The strength of vitamin
k-2. Tampa Bay Times, p. 5.
Wiggy. (2016, March 22). Different types
of vitamin K (k1/k2/mk-4/mk-7) explained. (Online Video Recording).
Videos: Health As It Ought To Be. Retrieved July 11, 2017 from https://www.youtube.com/watch?v=o7BUBeCQev4
