Not this K2.
The title article is from MEDSCAPE , a mostly-plain-English news, reference & med-journal repub’n website geared for professionals but FREE to all who register - you’ll get a popup form when you first click on a Medscape link, like the one for the title article.
Which reviews the current state of medical knowledge on Vit K, from & for healthcare professional viewpoint. After exerpting a bit from that, I’ll mention and link another article from another source, and some related information. (For anyone who wants to learn what healthcare professionals think and why about a great range of issues, and how to be equipped to meet that thinking with our own, read the literature they get their info from.)
Some exerpts from the 3 very readable pages at the top link:
Since its discovery nearly 90 years ago, vitamin K has enjoyed the uncomplicated status of an essential nutrient, respected but somewhat overlooked. Guidelines advised that we get our daily recommended intake of vitamin K ... but most likely made no mention that it exists in two variants, K1 and K2.
Beginning in the 21st century, however, researchers started closely scrutinizing the structural differences between K1 and K2, which before had been considered largely irrelevant.[2] Their work has indicated that K2 may deserve special consideration as a treatment for osteoporosis and cardiovascular disease.
How Do Vitamins K1 and K2 Differ?
The umbrella term vitamin K actually describes a family of fat-soluble compounds. The body has limited ability to store the vitamin and amounts are rapidly depleted without regular dietary intake.
Vitamin K1, also known as phylloquinone, is primarily found in green leafy vegetables. K1 accounts for approximately 90% of daily vitamin K consumption in the United States.[3]
A chart at this point in the article shows some food sources for K1, and how much from what, under optimal agricultural conditions ... which are rare...
Vitamin K2, also known as menaquinone (MK), is primarily bacterial in origin. K2 is mostly encountered in fermented foods, meats, and dairy products.[4] It is further subgrouped based on the length of its side chains, from MK-4 to MK-13.[4,5] For example, meat products typically include the MK-4 variants, whereas the traditional Japanese vegetarian dish natto ,made from fermented soybeans, contains MK-7, which provides the highest known vitamin K activity. K2 can also be produced by the human gut's microbiome, though the absorption and transport of K2 produced in this manner is less understood.[1]
A chart with similar information for K2 — ibid.
K2 comes to us primarily through products derived from animals, who can synthesize it from the K1 they ingest from eating grass.
As agricultural practices have shifted animals away from grassy pastures toward grains, K2 levels have decreased.[2] Because K2 is usually present in only modest amounts, and even less so in low-fat and lean animal products, many Western diets are inadequate providers of a nutrient researchers consider increasingly important...
...Bone Health
Vitamin K's bone-building reputation is well earned, as it is necessary for activating proteins secreted by osteoblasts… K2 draws calcium into the bone matrix and can inhibit bone resorption when administered with vitamin D3... The MK-7 form of vitamin K2 has proven particularly adept in this process.
A coupla link-heavy paragraphs next document authoritative research on K2 in osteoporosis.
Cardiovascular Disease
K2 activates matrix Gla protein (MGP), which keeps calcium deposits from forming on vessel walls. Research has shown that adequate K2 intake generally frees calcium up for its more beneficial roles, whereas K2 deficiencies will lead to a buildup of calcifications...
This simple cause-and-effect relationship was on display in the 2004 prospective population-based Rotterdam Study, which included 4807 individuals with no history of myocardial infarction... After following the cohort for up to 7 years, researchers reported that high K2 intake led to significant risk reductions in coronary heart disease, all-cause mortality, and severe aortic calcification when compared with those with the lowest K2 intake. In comparison, K1 intake had no discernible protective benefits.
A cohort study of over 16,000 women free of cardiovascular disease also reported a strong correlation between increased K2 intake and reduced coronary events, but not for K1...
In Japan, the article goes on to report, K2 is standard osteoporosis treatment. Elsewhere (e.g., the Us), studies comparing varying doses of MK-7 at various points in aging women’s lives haven’t nailed down what’s the optimal dose range of K2 for whom and when.
The next paragraph mentions concerns about whether calcium supplements create added cardiovascular disease risk, and if so could K2 rebalance that. Next is the finding that MK-7 is a form shown to interfere with anticoagulation therapy, yet “others like MK-4” don’t, “even at relatively high doses.[11]” so
awareness of the different properties of various K2 supplements is therefore crucial in patients taking anticoagulation therapy.
That’s it on that article. Next, also free, from ScienceDirect: Vitamin K: Redox-modulation, prevention of mitochondrial dysfunction and anticancer effect; Redox Biology, Volume 16, June 2018, Pages 352-358, Donika Ivanovaa, Zhivko Zhelevab. Plamen Getsovc, Biliana, Nikolovab. Ichio, Aokid,e, Tatsuya Higashid, Rumiana Bakalovad,e,f,d, https://doi.org/10.1016/j.redox.2018.03.013 (cf. Free Radical Biology and Medicine -a peer-reviewed scientific journal and official journal of the Society for Redox Biology and Medicine. The journal covers research on redox biology, signaling, biological chemistry and medical implications of free radicals, reactive species, oxidants and antioxidants. and others.) Downloadable pdf available by open access.
Wikipedia links are added in bold — sometimes those articles are clearer than in SciDir (other times not).
Abstract
This review is directed to the redox-modulating properties and anticancer effect of vitamin K. The concept is focused on two aspects: (i) redox-cycle of vitamin K and its effect on the calcium homeostasis [see also wik on that], “oncogenic” and “onco-suppressive” reactive oxygen species and the specific induction of oxidative stress [wik] in cancer; (ii) vitamin K plus C as a powerful redox-system, which forms a bypass between mitochondrial complexes II [wik] and III [wik] and thus prevents mitochondrial dysfunction, restores oxidative phosphorylation [wik] and aerobic glycolysis [wik], modulates the redox-state of endogenous redox-pairs, eliminates the hypoxic environment of cancer cells and induces cell death. The analyzed data suggest that vitamin C&K can sensitize cancer cells to conventional chemotherapy, which allows achievement of a lower effective dose of the drug and minimizing the harmful side-effects. The review is intended for a wide audience of readers - from students to specialists in the field...
,,,Vitamin K is a group of structurally related molecules ... two naturally occurring forms: vitamin K1 (phylloquinone) and vitamin K2 (menaquinone). There is also a synthetic form of vitamin K ... (K3 or menadione), which is classified as a pro-vitamin. Vitamin K1 exists only in one phylloquinone structure, while vitamin K2 exists in multiple structures…
...vitamin K influences the degree of carboxylation of osteocalcin – a small calcium-binding protein, which is secreted by osteoblasts in bones and serves as an integral protein for the synthesis of bone matrix [23], [24], [25]. The biosynthesis of osteocalcin is regulated by hormones and growth factors, but its post-translational modification is regulated by vitamin K….
...decarboxylated osteocalcin cannot bind calcium, which emphasizes the essential role of vitamin K [and in addition], vitamin K inhibits the activity of osteoclasts, thus preventing the breakdown of bones [27], [28]….
...Vitamin K participates in the carboxylation of the matrix Gla-containing protein (MGP) of the arterial walls and plays a crucial role in maintaining their elasticity [7], [8], [29], [30]…. MGP is produced in bones and vascular smooth muscle cells and inhibits vascular calcification [30], [31], [32]. Its function is affected by inflammatory factors [32]. The importance of MGP for vascular homeostasis was demonstrated on MGP-deficient animals – all of them died of massive arterial calcification within 6–8 weeks after birth [5], [33]. It was established that non-carboxylated MGP forms calcium depositions in the vascular walls [8], [27], [34]. The calcium phosphate crystals in the arterial wall directly attract macrophages and induce inflammation [27], [35], [36]. Studies have demonstrated that rats with vitamin K-deficiency and chronic kidney disease have an enhanced vascular calcification, which decreases after vitamin K supplementation [31], [37]. Warfarin, an inhibitor of vitamin K reduction, affects γ-glutamyl carboxylation of MGP and induces vascular calcification in experimental animals [4], [31], [34], [38]. The effect is abolished by vitamin K treatment [4], [31], [38]. These findings suggest that vitamin K-deficiency affects calcium homeostasis, which leads to vascular calcification and bone disorders.
How do I happen to keep an eye out for material like this?
I stumbled into learning to. Granted my previous working-life profession (research librarianship) was a huge plus.
But even before that, since my mid 20’s, I’ve had a weird heart-beat problem that for years only messed up my sleep because it only kicked when I would start to fall asleep anytime I was lying on my left side. The solution was obvious & easy. But it was very strange my Dr at the time didn’t think it was real. Wikipedia suggests to me it’s something to do with some kinda pre-cordial / parasternal heave but after years of monitors, exams, Drs scratching heads, I just don’t care anymore what its name is nor that there’s no Dx in my record because Drs can’t seem to help with it anyway. But taking K2 did!
Before I found K2, though, It got very painful following the car accident that ended up triggering severe disabilities (or maybe the drugs forced on me did, who knows...) A chance Rx for a beta blocker (atenolol) that research supposedly found useful for chronic fatigue syndrome, coincidentally took the pain down as a nice side effect. But with a sedating effect that grew worse and worse.
I’d reached desperation being trapped between on-the-one-hand immobilizing sedation —incapacitation, really, as if the chronic fatigue syndrome & fibro-fatigue weren’t exhausting enuf— or on-the-other-hand severe pain that might be involving very dangerous heart things happening.
Then I noticed that the Vit Kcomplex (of mostly K2) that I’d begun to take for nosebleeds (possibly familial &/or caused by overexposure to herbicides &/or petrochemical air pollution) was helping the thuddy heartbeat problem HUGE! My very respectful & nice but insistently non-specialist FamPrac primary care doctor wouldn’t do anything about finding an explanation except send me to yet another cardiologist or echocardio or sh*t, and I had HAD that (and the costs & exertions involved). So, I tapered off the beta-blocker on my own, done, finished, and stayed on the Vitamin K2 update note: still benefitting from it as of Dec 2020.
The two formal journal articles above clarify matters, but I only found them recently. Wikipedia’s article on calcium channel blockers (CCB) years ago first began to give me a dim notion . . .
...CCBs are ... effective against large vessel stiffness, one of the common causes of elevated systolic blood pressure in elderly patients.[4] CCBs are also frequently used to alter heart rate (especially from atrial fibrillation[thud thud thud thud?]), to prevent peripheral and cerebral vasospasm, and to reduce chest pain caused by angina pectoris.
...CCBs [are] slightly more effective than beta blockers at lowering cardiovascular mortality, but they are associated with more side effects...
. . . that calcium might be part of my heartbeat problem. So, I checked all my meds & nutritional suppls & convenience foods for calcium content, discovered they contained an astonishing amount, and switched to lower-or-zero calcium forms. And got improvement! And found that milk and cheeses, and other diary foods, caused little to zero ‘thud-episodes’, compared to the calcium-mono/di/phosphate chloride hooha this’n’that etc in pills and packaged foods.
But I was still puzzled why Vit K2 would help.
THEN I happened upon kosak <big>wilderness voice</big>’s Kosability diary, Vitamin K: Unsung and Essential several months after it was posted in 2013, and between the total of the information I’d read and that diary, the picture became quite clear. WV later posted two more with Vit K information:
and I recommend them all highly! Thank you, WV!
And now we have these 2 formal/professional articles, too. About time, yeh?
;-)