How Veterinarians Can Harness the Microbiome To Treat Bad Breath in Dogs

How Veterinarians Can Use the Microbiome To Treat Bad Breath in Dogs

Dental health concerns, particularly bad breath, are one of the most common issues seen in veterinary practices. In fact, bad breath is the third most searched topic amongst pet parents, after GI and skin issues. This is clearly an important topic for your clients and we want to support you with current information and resources to bring dental health to the forefront of your practice.

So, what causes bad breath? Periodontal disease is a common cause of bad breath, which affects approximately 80% of dogs by age three according to AVMA estimates. Bad breath can also be a symptom of serious underlying conditions originating outside of the mouth, such as liver disease, kidney disease, and diabetes mellitus. Lastly, a growing body of scientific evidence shows that bad breath can be a symptom of an imbalance in the oral microbiome and/or the gut microbiome.

Regardless of whether or not you have ruled out periodontal disease for a patient who has bad breath, it is important to understand the intricate ways the oral microbiome and gut microbiome influence dental health. In the article, we will cover how the oral microbiome and the gut microbiome affect dental health. We will also address how supporting both the oral and gut microbiomes can be used as a periodontal disease treatment or preventative treatment.

The Role Of The Microbiomes In Dental Health

Illustration of Porphyromonas gingivalis, a known dental pathogen, it negatively affects the gut microbiome

An Imbalanced Oral Microbiome Can Cause Bad Breath

One misconception is that particular bacteria are responsible for bad breath. While certain bacteria are associated with halitosis (chronic bad breath), that doesn't necessarily mean they are the true culprits of bad breath. These implicated bacteria live in low abundances on the tongue or in pockets in the gums of healthy pets, suggesting that an imbalanced oral microbiome is more likely the root cause of dental health issues.

The bacteria that make up the oral microbiome fill many different beneficial roles - from aerobic bacteria in biofilms that aid in remineralization of tooth surfaces to protecting against pathogens. An imbalanced oral microbiome may not be able to fulfill all of its functions, causing a self-perpetuating cycle of bad breath.

Left untreated, an imbalanced oral microbiome can lead to the progression of persistent inflammation of the mouth’s mucous membranes (stomatitis), destruction of the teeth and supporting bone (periodontal disease), and even oral cancer. It is important to note that good oral hygiene practices play a big role in creating an environment that promotes a healthy, balanced oral microbiome.

For example, some of the bacteria that thrive in the anaerobic environment of pockets caused by periodontal disease can produce sulfurous compounds that lead to a foul odor in a dog or cat’s mouth. A buildup of these bacteria can be prevented with routine dental check ups, subgingival scaling as needed, and regular teeth brushing.

The Oral Microbiome Influences The Gut Microbiome

Studies using next-generation sequencing methods have highlighted that oral and gut bacteria are much more similar than previously thought. And this makes sense: cats and dogs swallow a lot of saliva that has oral bacteria in it; inevitably some of those bacteria survive the stomach acid and end up in the gastrointestinal (GI) tract. In the case of periodontal disease, bacteria can also move from the mouth into the bloodstream, which could then result in gut dysbiosis due to chronic systemic inflammation.

Human medical research provides insights into the numerous ways that oral health can have profound impacts on the gut microbiome, and therefore overall health. For instance, researchers from the Virginia Commonwealth University found in their study that periodontal treatment positively altered the oral microbiome and gut microbiome. The subjects in that study had an improvement in symptoms of liver cirrhosis, a microbiome-associated disease.

Another study published in Nature’s Scientific Reports found that orally administered Porphyromonas gingivalis, a known dental pathogen, negatively affected the gut microbiome and exacerbated symptoms of rheumatoid arthritis, another microbiome-associated, immune mediated disease.

It’s A Two-Way Street: The Gut Microbiome Affects The Oral Microbiome

Recent studies in human medicine are beginning to identify ways in which the gut microbiome indirectly influences the oral microbiome. This 2020 study, for example, outlines how a dysbiotic gut microbiome in a state of chronic inflammation can trigger inflammation in many areas of the body. Systemic inflammation subsequently alters the makeup of other local microbial communities, including the oral microbiome.

We know from research on the gut-brain axis that gut microbes communicate with other areas of the body through neural, endocrine, cell-mediated immune, humoral, and metabolic mechanisms. While presently understudied, the gut microbiome and oral microbiome are likely connected in such ways; dysbiosis in one will likely trigger dysbiosis in the other. Furthermore, the progression of gut microbiome-associated diseases can have adverse, albeit indirect, effects on the oral microbiome by impacting lifestyle choices, such as diet and exercise.

In rare cases, the gut microbiome can directly cause bad breath too: volatile organic compounds caused by an overgrowth of bacteria in the small intestine can be absorbed into the bloodstream and exhaled, causing bad breath.

Microbiome Support Can Be An Effective Treatment And Prevention Tool For Dental Health

Halitosis in Dogs and Cats - Diet has significant impacts on the cat and dog gut microbiomes.

In addition to good dental hygiene practices, oral and gut microbiome support can be an effective intervention and preventative treatment for the root causes of bad breath. Current research points to dental health as a whole body approach, microbes included.

A balanced oral and gut microbiome is critical for combating and preventing bad breath in your patients. Here we discuss three main ways you can help support the dental health of cats and dogs from the perspective of the microbiome.


The diet has significant impacts on the microbial communities in cats and dogs. In some cases, a simple diet change can resolve microbiome imbalances. Talk to your clients about their pets' food, treats, and supplements while keeping in mind how they may affect dental health.

Nutrition impacts dental health in several ways. First, some vitamin and mineral deficienciesare associated with the progression of periodontal disease. Second, nutrient imbalances,such as too many carbohydrates, can cause inflammation in the gut microbiome which can lead to bad breath. Lastly, some animals are allergic to ingredients found in pet food and treats, which can have negative consequences for the gut microbiome.

There are additions you can suggest to pet parents to promote dental health as well. For example, dietary prebiotic supplements like TEEF, which is added directly to a dog’s water bowl, promote the growth of beneficial oral bacteria. This is a great recommendation for pet parents of cats and dogs who are unlikely to accept teeth brushing. While TEEF is currently customized for dogs, it is still safe for use in cats and the company is working on a supplement for cats.

Supervised chewing on bones helps reduce tartar buildup, which positively impacts the oral microbiome. While cats don’t chew bones like dogs do, the raw food community advocates for feeding cats whole carcasses (including tendons and bones), which serves the same purpose.

Microbiome Testing

Microbiome testing is a very helpful tool for both treatment and prevention strategies. Oral microbiome and gut microbiome tests for dogs are an invaluable tool for guiding treatment because they can identify dysbiosis, missing beneficial bacteria, existing pathogenic bacteria, and diet-induced dysbiosis. We also offer a Gut Health Test Bulk Pack for veterinarians.

Regular diagnostic testing is also a great prevention strategy because it can catch issues early, sometimes even before any symptoms arise. Testing healthy patients has it’s benefits too; it can give you a baseline for their microbiome, so it is easier for you to address microbiome-associated issues if they come up in the future.

Microbiome Restoration

In this article we have established that imbalances in the oral and gut microbiomes are not only connected, but have significant impacts on dental health. Although still a relatively new field of study, manipulating the oral microbiome is showing promise as a possible novel intervention for disease treatment and prevention.

A mounting body of scientific evidence over the last decade points to fecal microbiota transplants (FMTs) as a safe and effective way to resolve gut microbiome imbalances. Bad breath, GI symptoms, and skin problems are the top three most searched issues for pet parents, all three of which have been shown to be improved with a FMT.

Our Gut Restoration Supplements are an FMT in a capsule; they introduce a complete and balanced microbial community native to the GI tracts of cats or dogs.

Key Takeaways

  • Good dental hygiene practices are the first line of defense for oral health, but the oral and gut microbiomes play an important role too.
  • Bad breath is caused by “bad” bacteria’ is a myth. Rather, imbalances in the oral microbiome are likely to blame.
  • Chronic imbalances in the oral microbiome can lead to several diseases, especially periodontal disease.
  • The health of the oral microbiome can directly and indirectly impact the health of the gut microbiome, and vice versa.
  • Nutrition, food allergies, treats, and pre/probiotics are important to consider for a healthy oral microbiome.
  • Gut and oral microbiome testing can pay dividends as both a preventative tool and diagnostic tool for your patients.
  • FMTs are an effective way to restore microbiome health.

Two Oral Health Tests and a 30-day supply of TEEF.

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Two Gut Health Tests plus 60 Capsules of Gut Restore Supplement.

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Two Gut Health Tests plus 60 Capsules of Gut Restore Supplement.

Sold out