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3 connections every dental hygienist should know about gut and oral health

June 21, 2023
There's a lot of buzz about "gut health" these days. But do patients really understand what it is? We can step in to explain it and how it relates to diet and oral health.

Gut health is a trending topic. With all the new information about the bacteria that inhabits our colons (the gut microbiome) and how they impact our overall health and inflammatory responses, it’s no wonder dental hygienists are intrigued by this topic. But how exactly does the gut microbiome relate to oral health and vice versa? What exactly should we, as oral disease prevention specialists, know about the connection between oral and gut health? 

While oral bacteria and gut bacteria are their own entities with varying differences at polar ends of the digestive tract, they impact people on a systemic level.1 Here are three simple facts every hygienist should know about gut health, and how we can talk to our patients about improving their overall health.

You might also be interested in: Understanding probiotics and the oral-gut axis: It's a gut feeling

Gut health impacts oral health

Our gut microbiome is comprised of trillions of microorganisms that impact the overall immune response.1 When gut bacteria are in a state of dysbiosis (imbalance), chronic inflammation often results. With a heightened immune response, oral pathogens are more likely set off by heightened gingival reactors, leading to the presence of gingivitis or a periodontal autoimmune response.1

While not flossing at home is a key element of gum disease, we’re frequently faced with patients who have great home care and little plaque or calculus, yet they can’t seem to shake the bleeding gums. The appearance of gum disease in these patients may be a result of leaky gut and/or dysbiosis of the gut microbiome.1

Oral bacteria contribute to leaky gut

Under healthy circumstances, the oral microbiome and the gut microbiome do not interact. In healthy individuals, the bacteria from the oral cavity are killed by strong gastric acids in the stomach.1 However, when periodontal pathogens are present in the oral cavity, they create inflammatory signals that are released, leaving way for these pathogens to circulate systemically.2 These periodontal pathogens have been found to inhabit the outer layer of the gut.1,2 When enough of these bacteria are present, holes or breaks form in the thin and absorbent lining of the gut.1

P. gingivalis has been shown to be acid-resistant, which allows the bacteria to pass through the GI tract unharmed.1,3 This introduction of pathogens into the colon contributes to dysbiosis of the gut microbiome, causing similar tears in the gut lining from the inside.2 These tears are commonly referred to as leaky gut.4 This allows bacteria to enter the bloodstream, inducing a state of chronic inflammation and an array of chronic diseases such as diabetes, auto-immune disease, and even some forms of cancer.1,3,4

How nutrition can positively impact oral and gut health

Nutrition is an easy topic to discuss with patients when it comes to oral and gut health. These have a synergistic effect, and often when seeking to create a healthy gut microbiome, one can also create a healthy oral microbiome and vice versa. There are several ways to improve through nutrition, and here are my top three.

Fiber: Fiber is the portion of plant-based foods that is indigestible in the GI tract. It helps regulate digestion and provides food for the good bacteria in our gut. The more food provided to the good guys, the faster they multiply and spread.1,4,5 On the other hand, foods such as sugar and hydrogenated oils can lead to the overgrowth of bad gut bacteria.4 Fiber also enriches the oral microbiome and aids in cleaning teeth by helping remove plaque and bacteria from the tooth surfaces.

Omega 3: Omega 3 is an essential fatty acid and a well-known anti-inflammatory. Omega 3 has been shown in several studies to improve the outcomes of periodontal therapy when taken as an adjunct supplement.2,6,7 The same thing is true for the gut microbiome. Omega 3 has been shown to aid in the overall reduction of inflammatory responses, aid in the improvement of insulin resistance, and promote the growth of positive gut bacteria.4,8

Reducing sugar: Sugar, which we are very familiar with as dental hygienists, is the key element when initially addressing caries prevention. However, there are other reasons why sugar should be significantly reduced. When sugar is introduced to the oral cavity, it creates an acidic response and leads to the growth of harmful bacteria in the mouth.1,2 The same thing holds true for the bacteria found in the gut. Sugar promotes the bad guys, leading to dysbiosis.1 Reducing sugar intake can benefit the oral and gut microbiomes.

While the research on the human microbiome is just getting started, the evidence of both oral microbes and gut microbes on chronic inflammation and systemic health is abundant. As dental hygienists, we know the importance of a healthy immune system in optimizing oral health. Thinking outside the box regarding what might be enhancing the host response to oral pathogens can help our patients heal. We are prevention specialists who help develop not just healthy gums, but overall healthy humans. Remember, in many cases our patients see us more than they see their physicians. Start the conversation about ways to develop overall health!


  1. Khor B, Snow M, Herrman E, Ray N, Mansukhani K, Patel KA, Said-Al-Naief N, Maier T, Machida CA. Interconnections between the oral and gut microbiomes: reversal of microbial dysbiosis and the balance between systemic health and disease. Microorganisms. 2021;9(3):496. org/10.3390/microorganisms9030496
  2. Lu M, Xuan S, Wang Z. Oral microbiota: A new view of body gealth. Food Sci Human Wellness. 2019;8(1):8-15. doi:10.1016/j.fshw.2018.12.001
  3. Van Dyke TE, Bartold PM, Reynolds EC. The nexus between periodontal inflammation and dysbiosis. Frontiers in Immunology. 2020;11. doi:10.3389/fimmu.2020.00511
  4. Usuda H, Okamoto T, Wada K. Leaky gut: effect of dietary fiber and fats on microbiome and intestinal barrier. Int J Moled Sci. 2021; 22(14):7613. https://doi.org/10.3390/ijms22147613
  5. Tennert C, Reinmuth AC, Bremer K, et al. An oral health optimized diet reduces the load of potential cariogenic and periodontal bacterial species in the supragingival oral plaque: A randomized controlled pilot study. Microbiol Open. 2020;9(8). doi:10.1002/mbo3.1056
  6. Chatterjee D, Chatterjee A, Kalra D, Kapoor A, Vijay S, Jain S. Role of adjunct use of omega 3 fatty acids in periodontal therapy of periodontitis. A systematic review and meta-analysis. J Oral Biol Craniofacial Res. 2022;12(1):55-62. doi:10.1016/j.jobcr.2021.10.005
  7. Heo H, Bae JH, Amano A, Park T, Choi YH. Supplemental or dietary intake of omega‐3 fatty acids for the treatment of periodontitis: A meta‐analysis. J Clin Periodont. 2022;49(4):362-377. doi:10.1111/jcpe.13603
  8. Noriega BS, Sanchez-Gonzalez MA, Salyakina D, Coffman J. Understanding the impact of omega-3 rich diet on the gut microbiota. Case Reports in Medicine. Volume 2016. Article ID 3089303. 10.1155/2016/3089303

About the Author

Christina Eggleston-McKenzie, MSFN, RDH

Christina Eggleston-McKenzie, MSFN, RDH, has been a practicing dental hygienist in Atlanta, Georgia, for 10 years. She holds a master’s degree in functional nutrition and has a nutrition coaching business in which she specializes in gut health. Christina loves to bring the world of nutrition to her hygiene patients and understands the powerful role of prevention in achieving optimal health.