gut microbiome

It’s well-known that oral health greatly impacts gut health. But just how connected is dental health to gut microbiome? Discover just how deeply linked the oral health of pets is to the health of their gut, and why it’s so important to understand this process to help your dog thrive.

The gut and how it functions

The gut is a tube that starts in the mouth, travels through the body and ends at the anus – both ends are exposed to the environment. The gut comprises numerous habitats that range in acidity, oxygen and mucus concentrations, percentage of moisture and nutrient availability.

The entire tube is colonized by microbiota, the composition of which varies significantly, with the highest diversity and burdens located towards each end of the tube. The durable mucosal lining of the tube serves as a semipermeable barrier, allowing for absorption of individual nutrients and water but blocking the transit of microbiota into the body. With the exception of leaky gut (inflammatory bowel disease) and leaky gums (gingivitis), this tube has amazing repair properties, if left to heal.

In human and veterinary medicine, the microbiota of the gut is held in the highest importance, and it is treated in a manner that is separate from the oral microbiota…but is it really that distinct? Evidence suggests the microbes from one end of the tube may actually affect the microbiota from the other end of the tube, and that dysbiosis towards one end correlates with dysbiosis towards the other end, as well as the presence of inflammation.

Research has shown that hosts with systemic diseases, such as inflammatory bowel disease and arthritis have altered oral microbiota. [1,2] Similarly, orally-derived microbes have been reported to be enriched in the lower gut of hosts with systemic disease. [3,4,8] Studies have shown that the most commonly found orally-derived microbiota present in the gut are members of the Prevotella, Veillonella, Streptococcus, Fusobacterium genera. [4] Interestingly, recent studies have shown that Porphyromonas gingivalis, a periodontal pathogen, can alter the composition of the microbiota in the lower gut and orally-derived Klebsiella can colonize and induce mucosal inflammation in the gut. [5-7]

Indeed, in our own studies, we have observed a significantly high abundance of enterics, such as Klebsiella, Enterobactericiae and others in the oral microbiota of dogs with periodontal disease, and high amounts of Fusobacterium and Prevotella in fecal samples from the same dogs.

The question we are wrestling with is: does dysbiosis at one end of the tube drive dysbiosis at the other end of the tube?

Veterinarians report that dogs on our dental prebiotic, Protektin42, which is designed to improve the oral microbiome in dogs with dental dysbiosis, not only have improved gingival health but also experience better bowel movements. We are currently looking to validate these observations with clinical studies which will be designed to begin to address the question: if we can eradicate dysbiosis on the oral side of the tube using Protektin42, can we also eradicate dysbiosis towards the other end of the tube?


1. Said, HS. Et al. 2014. Dysbiosis of salivary microbiota in inflammatory bowel
disease and its association with oral immunological biomarkers. DNA Res. 21, 15-25.
2. Zhang, X. Et al. 2015. The oral and gut microbiomes are perturbed in rheumatoid
arthritis and partly normalized after treatment. Nat. Med. 21, 895-905.
3. Kostic, AD. Et al. 2013. Fusobacterium nucleate potentiates intestinal tumorigenesis
and modulates the tumor-immune microenvironment. Cell Host Microbe. 14, 207-
4. Lira-Junior, R. And Bostrom, EA. 2018. Oral-gut connection: one step closer to an
integrated view of the gastrointestinal tract? Muc. Immunol. 11, 316-318.
5. Atarashi, K. et al. 2017. Ectopic colonization of the era bacteria in the intestine
drives a Th1 cell induction and inflammation. Science. 358, 359-365.
6. Arimatsu, K. Et al. 2014. Oral pathobiont induces systemic inflammation and
metabolic changes associated with alteration of gut microbiota. Sci. Rep. 4, 4828.
7. Olsen, I. And Yamazaki K. 2019. Can oral bacteria affect the microbiome of the
gut? J Oral Microbiol. 11:1586422.
8. Benahmed, AG. Et al. 2021. Association between the gut and oral microbiome with
obesity. Anaerobe. 70:102248.

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Emily Stein, Ph.D. founded Primal Health (TEEF for Life) in 2017 to focus on improving the dental health of both humans and animals by producing oral microbiome modulation products. She has spent 12 years developing Selective Microbial Metabolism Regulation Technology (SMMRT™) at Primal Therapies, Inc., which is focused on using metabolic influencers to re-engineer disease-causing bacterial biofilms into those that are health-promoting, to decrease inflammation and to improve outcomes. Prior to that, she spent 7 years as a research fellow at Stanford University in Rheumatology and Immunology focused on the neuro-endocrine-immune axis in autoimmune and chronic inflammatory diseases. She holds a Ph.D. in Microbiology from the University of California at Berkeley where she studied inter- and intra-cellular signaling pathways involved in stress response and community development in bacteria and received her B.S. in Microbiology and Immunology at the University of Iowa where she studied the interaction between M. tuberculosis and innate immune cells.


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