Subclinical atherosclerosis is linked to small intestinal bacterial overgrowth via vitamin K2-dependent mechanisms (Ponziani et al.)
The results of an observational study that have recently been published in the World Journal of Gastroenterology demonstrate that vitamin K2 supplementation may be of great therapeutic value to patients diagnosed with small intestinal bacterial overgrowth (SIBO).1
SIBO is defined as the presence of excessive bacteria in the small intestine, and it is frequently implicated in causing chronic diarrhea and malabsorption. Patients with SIBO may also suffer from unintentional weight loss, nutritional deficiencies, and osteoporosis. Several diseases of the gastrointestinal tract, wherein gut bacteria act in a pathogenic capacity, are associated with vascular dysfunction and increase the risk of atherosclerosis in the host. Moreover, recent studies have highlighted that patients with small intestinal bacterial overgrowth (SIBO) have low circulating levels of vitamin K2.2
The aim of this study was to investigate the rate of MGP carboxylation (the protein, which helps to prevent calcium from accumulating in arterial walls) in patients with SIBO and to decipher its association with the risk of developing subclinical atherosclerosis. To that end, researchers enrolled 39 patients into the study, and 12 of them were diagnosed with SIBO (30.8%). Vascular assessment was carried out by ultrasound examination. Plasma levels of the inactive form of MGP (dp-ucMGP) were measured in blood and vitamin K2 intake was estimated using a food frequency questionnaire. Patients with SIBO presented with a higher concentration of inactive form of MGP. Arterial stiffness was elevated in the SIBO group and this phenomenon was reported to correlate linearly with the levels of inactive MGP. Carotid intima-media thickness and arterial calcifications were not observed to be significantly elevated as compared to controls.
In conclusion, patients affected by SIBO have higher levels of inactive MGP as well as increased arterial stiffness both of which are early markers for vascular dysfunction. Authors of the study suggest that vitamin K2 supplementation and the treatment of intestinal dysbiosis may be therapeutic alternatives of significant utility.
1 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 Journal of Gastroenterology. 2017;23(7):1241-1249. doi:10.3748/wjg.v23.i7.1241.
2 Giuliano V, Bassotti G, Mourvaki E, Castellani D, Filippucci E, Sabatino G, Gizzi S, Palmerini F, Galli F, Morelli O, Baldoni M, Morelli A, Iorio A. Small intestinal bacterial overgrowth and warfarin dose requirement variability. Thromb Res 2010; 126:12-17 [PMID: 20051286 DOI: 10.1016/j.thromres.2009.11.032]