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The Link Between Small Intestinal Bowel Overgrowth (SIBO) and Cardiovascular Risk

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There is burgeoning evidence that gut health and the microbiome have direct links to artery disease. Arterial disease is the main way we develop cardiovascular problems. When arterial plaque develops it can cause either a stroke or heart attack when it ruptures. The plaque may also become so extensive that it completely blocks the artery over time. Additionally, arterial disease in the brain is a common cause of dementia.

SIBO and Its Association with Other Diseases

Small intestinal bacterial overgrowth (SIBO) is the presence of excess colonic bacteria in the small intestine. In contrast to the large intestine, the concentration of the bacteria in the small intestine rarely exceeds 1,000 organisms/ml. This is because gastric acid secretion and intestinal motility limit the overgrowth of bacteria in the small intestine. When these protective mechanisms against excessive bacterial growth fail, small intestinal bacterial overgrowth (SIBO) can result.

SIBO is associated with several symptoms that typically include gas, abdominal pain, nausea, fatigue, diarrhea, constipation, and bloating. This condition may also irritate the liver. Associations with other diseases have been established and they include rosacea, interstitial cystitis, prostatitis, restless leg syndrome, and fibromyalgia. [1]

Related Post: New Research on the Cause of SIBO

The Effect of SIBO on Vitamin K2 and Arterial Health

Intestinal bacteria are the main source of vitamin K2 in the human body; more than diet. SIBO alters the production of K2, leading to a relative K2 deficiency. The main types of K2 that we are interested in are vitamin K1 and vitamin K2. K2 is most important for arterial health. Vitamin K2 works with the matrix GLA protein to maintain arterial health, flexibility, and prevent arterial calcification.[2]  The GLA protein regulates calcium entry into arteries.

Several studies have established an association, but I find it more interesting looking at the causation.

Another way the microbiome is involved is through the production of a metabolite called trimethyl amine-N-oxide (TMAO). The foods most likely to raise TMAO levels include red meat, eggs, and cheese.  These foods contain carnitine and/or phosphatidylcholine. An imbalanced and unhealthy gut microbiome can turn these substances into TMAO. TMAO is directly linked to arterial disease, heart disease, and kidney disease. [3]  TMAO levels tend to be lower in pure vegetarians (but not always), and tend to be higher the more meat, cheese, and eggs someone eats. Despite this, treatments work without taking the animal food out.

Assessing Your Cardiovascular Risk from SIBO

Are you concerned you may have SIBO? Or, do you already know you have SIBO and would like to assess your associated cardiovascular risk? At NatureMed, we can test your Vitamin K2 levels, perform tests to diagnose SIBO, and check your arterial plaque.

Call our office at 303.884.7557 to schedule an assessment.



[1] Adkins C, Rezaie A. Small Intestinal Bacterial Overgrowth and Coronary Artery Disease: What Is in the CArDs? Dig Dis Sci. 2018 Feb;63(2):271-272.

[2] Ponziani FR, Pompili M, Di Stasio E, Zocco MA, Gasbarrini A, Flore R. Subclinical atherosclerosis is linked to small intestinal bacterial overgrowth via vitamin K2-dependent mechanisms. World J Gastroenterol. 2017 Feb 21;23(7):1241-1249.

[3] Tang WH, Wang Z, Levison BS, et al. Intestinal microbial metabolism of phosphatidylcholine and cardiovascular risk. N Engl J Med. 2013;368:1575–1584.