top of page

Gut Link: SIBO and Vascular Disease

The fascinating association between dysbiosis and vitamin K2, and how this influences the health of your blood vessels.

Could a messed-up microbiome be on of the major sources of stiff blood vessels and a harbinger of future vascular disease?

On the cutting edge of health research

It has been estimated that clinical practice (in the U.S. at least) is somewhere around 12 to 17 years behind the leading research. One of the great aspects of Functional Medicine is that many of its practitioners do their best at staying on top the latest research and trying, as much as possible, to incorporate these findings into the way they treat their patients. The articles in this website are written in an effort to synthesize the latest research into a form that is usable to my readers with the hope of enabling them to achieve optimal health, beginning with the gut and extending to every other aspect of their person: body, mind, and soul. Below is a summary of gut-related research and the way it demonstrates what I call the "Gut Link." Hippocrates wasn't far off when he stated centuries ago: "All disease begins in the gut." Research is showing, more and more, that many diseases DO begin with a messed up gastrointestinal system that may not show up as typical GI symptoms like diarrhea, constipation, bloating, abdominal pain, and the like. Instead it may be quietly promoting the development of mood disorders, autoimmune disease, skin problems...and the list goes on and on. In the study reviewed below we see more evidence for the "Gut Link" between a dysfunctional GI tract and vascular disease, and it brings in the fascinating aspect of vitamin K2--a nutrient that is gaining importance as we learn more about its function in the health of blood vessels. For more topics on gut health, GI conditions, and the "Gut Link," see my website at

What's so great about vitamin K2?

There is an increasing amount of data that shows the importance of vitamin K2. Did anyone hear much, if anything, about K2 before about 10 years ago? Even then most of the research was still in the lab. It turns out that since western diets are relatively deficient in K2 that we rely largely on our gut bacteria to make the forms of vitamin K that our bodies need--especially for the health of our blood vessels. Don't get me wrong, there are a lot of other functions in which K2 plays an important role such as bone health, testosterone regulation, insulin utilization, energy production, and possibly even cancer suppression. This article, however, focuses on the link between the health of your gut and the health of your blood vessels. Please see my other articles explaining the importance of K2 at

The link between SIBO and subclinical atherosclerosis

There are two forms of vitamin K: K1 and K2. Research has shown that K2 is important in preventing calcium deposition in your blood vessels and promoting proper maintenance of calcium in the bones.

One of the many important functions of the bacteria in our gastrointestinal tract (otherwise known as our gut microbiome) is to synthesize nutrients that may not be adequately supplied by our diets. Vitamin K is one of those nutrients. Research shows that western diets are significantly deficient in K2 so we rely largely on our gut bacteria to synthesize the K2 that we need. Even then it may not be enough. But what if our gut microbiome is messed up? Would that impair the ability of the gut bacteria to make K2? Would we then be even more deficient in K2 and even more susceptible to vascular disease such as atherosclerosis, hypertension, and the like?

What the research shows

Researchers in Italy set out to at least begin to answer this question and they published their findings in the World Journal of Gastroenterology [2017 February 21; 23(7):1241-1249]. In order to not bore you with the design and methods of the study, I will greatly summarize the results. Since calcium deposition in the walls of blood vessels is, to a certain degree, prevented by K2 it is reasonable to assume that those deficient in K2 would have a greater degree of arterial stiffness. The researchers measured the inactive form of matrix Gla-protein (MGP) which is a surrogate marker for K2 deficiency. They also measured the velocity of blood flow in major arteries since "stiffer" blood vessels have greater velocity of flow. They then compared measurements in 2 groups: those with SIBO and those who didn't have SIBO. When the results from the 2 groups were analyzed, it showed that the SIBO group had a greater degree of K2 deficiency and evidence of less compliant (greater stiffness in) carotid arteries. This is important because arterial stiffening is an early marker of blood vessel dysfunction which then potentially leads to greater problems in the future. Though this was a relatively small study, it at least gives us greater impetus to forge ahead in clinical practice to emphasize the need for gut health as well as K2 supplementation in many cases. It also gives greater urgency to the proper treatment of SIBO. Yes, SIBO causes a lot of discomfort and impairs quality of life. But it's much more than just a functional bowel problem (as many have said). It's a real risk to overall health and requires REAL treatment--at the root cause.

Get more insight on the latest GI research at


bottom of page