There is far too often a mentality to jump out of the frying pan and into the fire with vitamin dosages.
Vitamin K, as many vitamins can, represents an excellent example of this principle. First, vitamin K activates or builds proteins to participate in coagulating blood, especially when injured or cut. The body adapts this mechanism to deal with a wide variation in vitamin K levels. This issue will be discussed below with vitamin E influence. The issue here is with some other functions of vitamin K. 
Vitamin K is involved in activating a vitamin D built protein called Osteocalcin. One of the functions of this protein is to bind calcium into bone mineral crystals. For this function to progress, vitamin K is needed to activate, or carboylate osteocalcin. ref At any one time in the blood, some osteocalcin is carboxylated by vitamin K and some is not. ref Doctors have for quite some time been measuring the amount of osteocalcin that is carboxylated to represent bone building activity, but never mentioned what they were really testing was vitamin K activity level.
Osteocalcin forms are also involved in blood sugar control, insulin production by beta cells, as well as immune system activation against certain cancers. Research found that in test tube studies, the different forms of osteocalcin showed opposite actions on prostate cancer growth. The proper balance is needed to limit cancer growth.
NOTE: Studies looking at the association between blood sugar control and vitamin K have to also check the ratio of cOC to ucOC in subjects since it is this balance that really regulates glucose insulin in blood and not vitamin K directly. Studies that do not could and have arrived at nil or opposite results.
Another important function for vitamin K is to activate proteins in the arteries called matrix GLA that function to limit calcium build up in the artery wall. Please read this Cardiologist blog on K2. ref
Seems logical to just load up on vitamin K if heart health or bone density are issues. But it is not that easy. Vitamin K comes in 3 forms, K1, K2 as MK4, and K2 as MK7. Plus, subforms of each also exist as cis and all-trans forms, just like beta carotene. All vitamin K forms function to build coagulation proteins, but only K2 appears to do the other functions. Since MK4 only has a short shelf life in the body, about 8 hours, large dosages are needed, while MK7 stays active in the body for 3 days, and thus very low dosages will suffice. Some vitamin K1 from dietary greens converts into K2 as MK4 in the body to help build bone, plus provide another vital function of carboxylated osteocalcin, directing, ref , the regulation of blood sugar levels controlling insulin resistance. ref The exact amount of vitamin K and the ideal form or forms to supplement that are most effective to maintain all functions optimally is still under study, and it should be a high priority. But, evidently, it is not judged by the lack of quality research. This new 2022 study has great insights about vitamin K and who should especially consume it. ref Odd that so much research comes out of Europe rather than the USA.
CAUTION: Most research on Osteocalcin (OC) occurs with mice. Osteocalcin is involved in bone building and in preventing the bone building process occurring in soft tissues where it should not happen. Early results from these mouse studies provided theories for later human testing. BUT, the human testing revealed vast differences in how the involved elements functioned. Osteocalcin was found to form at least 12 different forms. The two major forms are the un-caboxylated (unOC, GluOC) and the vitamin K carboxylated (cOC, or GlaOC). In mouse studies, the unOC form regulated blood sugar while in humans it appears that the cOC may be the active form. Very confusing since most scientific articles talk about the mouse study results like they apply to humans. The human issue is not yet completely solved as disease states can also influence OC levels. ref
CRITICAL: Now another issue has surfaced. It was discovered that bone issues are involved with prostate cancer. Bone is more than just a structure for support. It is also a regulator of immune functions. OC appears to have hormone functions in these areas as well. A study found that a balance was needed between unOC and cOC. The OC form unOC inhibited prostate cancer cell growth while cOC promoted. ref While the two forms overlap some in these areas, the exact roles and ratios between the two forms that is needed to control and normalize prostate cell growth is still unknown. This is very new. While this finding is from a test tube study on prostate cancer cell lines, it highlights the balanced approach needed to optimize vitamin functions for maximum health maintenance. Even beneficial nutrients for one function, like vitamin K on bone, have to be evaluated for other functions like K on artery calcification inhibition and prostate cell growth regulation.
For more information on vitamin K, read this article. For a Doctor's take. <Caution, this Doctor is associated with selling products described.
Vitamin D presents another example of a nutrient with many of these vitamin issues.
The precautionary approach takes front seat for vitamin K as well as vitamin D. Better to error slightly on the low side rather than go too high. The new vitamin criteria mentions it might be prudent to take vitamin K2 as MK7 at 45 or 90 mcg every day for about 10 days, and then just every other day or even every third day for the 90 mcg size, unless under medical care. Since both forms of Osteocalcin, unOC and cOC, are involved in many functions, the exact ratio between the two for proper actions in all functions is still to be determined. Check foods consumed for dietary amounts to get an idea for supplement amounts or even if supplements are needed at all. Your intestinal bacteria make some vitamin K2. Another reason to feed these little bugs the right foods that they like. article
VITAMIN K METABOLITE on LOW BONE DENSITY
There are processes that can convert vitamin K into different forms. In foods that contain partially hydrogenated fats, another term for trans-fats, another form of vitamin K is often produced by the hydrogenation process. This form is called dihydrophylloquinone. Consuming foods with this vitamin K form increase dihydrophylloqinone levels in the body and have become associated with low bone density. ref ref
FYI VITAL: New joint study out of USA and China found higher K2 as MK form was associated with slightly higher risk and mortality of breast cancers. ref This needs immediate verification. If MK was just from food, were the foods in any way a factor. MK form of vitamin K2 foods include cheeses, meats, butter, etc. Would using a low dose K2 as MK7 from natto or chickpeas bypas this risk and still give bone and blood sugar control???
About Trans Fats
It could be that this unique form of vitamin K interferes with the actions of the regular vitamin K form for building strong bones. Research indeed does reveal lower levels of regular vitamin K in tissues when dihydrophylloquione vitamin K form is present.
OF INTEREST: A remarkable aspect of this research is that there appears to be a lack of follow up studies to either verify or negate the findings, or expand on the significance and consequences of lower bone density related to this vitamin K metabolite presence. Here* is one many years later. This article simplifies the issue. Dihydrophylloquinone is ONLY found in foods with partially hydrogenated fats.There may be a another direction to look for related research following Trans Fat links to bone health.
* This study is rather interesting in comparing canola oil, to regular soy oil versus hydrogenated soy oil on a particular bone marker. This marker is found in greater amounts when vitamin K2 is deficient. Even though the results showed increased bone growth, the ectopic bone that is formed is not a desirable bone process and leads to increased cardiovascular disease. ref Ectopic bone formation after hip surgery is a result of lack of motion early enough to overcome the ectopic bone formation process. ref
NOTE on Trans versus Cis forms of MK7
Vitamin K2 exists in many forms throughout the animal kingdom. In Humans, vitamin K2 has two significant forms, MK4, and MK7. In the body, MK4 is the dominate K2 form found and it is naturally produced from K1 by intestinal bacteria. MK7 is found in fermented soy food called natto and in fermented cheeses. ref MK4 is also found in meats and dairy. Plus, these forms also exist in the Cis form and the Trans form. You will see mentioned that the Trans form is the only active form. This is simple not true. The Cis form of MK7 does has some activity, but not nealy as much as the Trans form. ref It is the opinion of this author that Mother Nature may have a special plan for putting some Cis in with a lot of Trans MK7 form in foods. The Cis form might serve a balancing effect to not let the Trans form overcook the carboxylation of certain proteins. This is similar to how the two forms of vitamin D behave.
VITAMIN K, Vitamin E, and Coagulation
Since Vitamin E and Vitamin K have similar compositions, with nearly identical side structures, they can block out one another for some processes that impact the side structures. Supplement protocols need to consider both nutrients when determining dosages to limit any interference. Consuming at separate meals will help eliminate this interference as well. Vitamin E as only alpha tocopherol is supplemented more than vitamin K
. Thus, the influence of vitamin E blocking out vitamin K absorption is well documented by research and deserves more study. New discoveries now know that vitamin E also can interfere with the vitamin K function of activating proteins to be used in the coagulation process.