We've always known that the mouth is important simply due to its function (after all, how else are you going to eat?), but research is starting to shed light on a previously underappreciated player in overall health: the oral microbiome.
What Is the Oral Microbiome?
The oral microbiome is the ecosystem of bacteria that exists in your oral cavity, which includes your mouth, ears, nose, and throat. While researchers have catalogued over 700 different types of bacteria in the oral microbiome, most people have a mix of about 300 of these species in their mouths.1
Like the gut microbiome, the oral microbiome functions best when it's in balance––the more beneficial bacteria like L. paracasei and S. salivarius, and the fewer not-so-good bacteria like S. mutans, the better. Also, similar to the gut microbiome, the composition of your oral microbiome changes according to your diet, how much water you drink, and your exposure to antibacterial hygiene products. (Many dental health products destroy bacteria indiscriminately, which can sometimes create conditions for undesirable bacteria to thrive.)
How the Oral Microbiome Affects Your Overall Health
It might seem counterintuitive to think that what happens in your mouth can affect your body as a whole, but studies have linked changes in the oral microbiome to everything from the health of your heart to your chances of having problems with your memory.
What's more, it looks like we get our very first exposure to microbes from our mother’s oral microbiome while still in the womb! Researchers have known for a long time that having unhealthy gums tends to correlate with certain types of birth complications, but the reason why is just now becoming clear.2 Studies show that bacteria travels from mom’s mouth to the placenta, giving babies their first exposure to microbes (both good and bad), and setting them up with a foundational microbiome that continues to grow and support them for the rest of their lives.3
How can such a seemingly insignificant part of the body have such a big impact? The oral microbiome affects your overall health in four main ways: by altering the gut microbiome, through the diffusion of bacteria into the bloodstream via the gums, by impacting the composition of saliva (and thereby digestion), and through its direct effects on upper respiratory health.
1. The Oral Microbiome and the Gut Microbiome
Your mouth leads directly into your gastrointestinal system, so some of the bacteria in it naturally pass to your gut as you eat and drink. You also swallow about a liter of saliva a day as part of your normal salivary flow. Higher concentrations of undesirable bacteria in the mouth––like P. gingivalis, associated with challenges to gum health––can increase the amount of unwanted bacteria in the stomach and intestines.4
Since the gut microbiome is the foundation of so many mechanisms of health throughout the body, tipping its scales in favor of the bad guys can have an extended effect on everything from the immune system (80% of which resides in the gut) to how well you sleep.5
2. When Unwanted Bacteria Enters the Bloodstream
Even if you set the gut microbiome aside, the bacteria in the oral microbiome can affect the body via your bloodstream.
To understand how, you need to know a little bit about the physical differences between the surfaces in the mouth and in the rest of the body. Teeth are the only non-shedding surfaces in the body (meaning they don't regularly lose and replenish cells), which allows for a thin layer of bacteria called biofilm to form on them. If undesirable bacteria in biofilm get out of control, it can have serious effects on the teeth and gums, and by extension, the rest of the body.6
It happens like this: when the balance of your oral bacteria tips in favor of the bad guys, they initiate an immune response in your gums which can cause your gum tissue to become delicate and breakable. When this happens, toxins and byproducts from the unwanted bacteria (and even the bacteria themselves!) can enter your bloodstream, giving them access to the rest of your body.7
Your immune system reacts to these substances by initiating temporary inflammation as it tries to get rid of the invaders. If the problem doesn't resolve itself, the immune response can lead to problems throughout the body. Besides the stress the ongoing reaction puts on the immune system, diffusion can also lead to changes in:
• Circulation and heart health.
Undesirable bacteria in the oral microbiome can cause a chain reaction in which your body can't use nitrite appropriately, which challenges the health of your circulatory system.8 Similarly, people who tend to have sudden changes in their heart function or circulation commonly have S. mutans in their heart valves.
• Blood glucose regulation.
Remember the full-body immune response related to bacteria in the bloodstream? That type of response is also one of the precursors to the body becoming unable to manage glucose and insulin correctly. Research shows that this relationship goes both ways: bacteria in the bloodstream can trigger the type of temporary inflammation that can lead to insulin issues, and the body being unable to regulate blood sugar leads to the formation of Advanced Glycation End products (AGEs), which encourage the growth of inhospitable bacteria in the mouth.9
• Memory and brain function.
Increased immune responses also play a key role on the health of your brain. When unwanted bacteria like A. actinomycetemcomitans and P. intermedia make it into the bloodstream, they cause the body to release cytokines as part of its immune response. But when the body releases too many cytokines over too long a period of time, they can start to weaken the the blood-brain barrier, allowing substances to cross into the brain and induce confusion, fogginess, and eventually, permanent changes in memory and brain function.10
3. Impacts on Saliva
Saliva plays a big role in maintaining the oral microbiome’s balance. Ideally, it acts as a buffer, keeping the mouth at a relatively neutral pH, which encourages the growth of beneficial bacteria and inhibits the growth of inhospitable species. It also contains a number of enzymes that are crucial to digestion. (We tend to think of digestion as starting in the stomach, but it actually starts in the mouth as enzymes soften and start to break down food while you chew.)
But when the balance of your oral microbiome gets out of whack, the pH of saliva shifts to the acidic end of the scale and the number of digestive enzymes drops. This means that food enters your digestive system more intact than it should be, making it harder for you to extract all the nutrients from it.11
4. Effects on Upper Respiratory Health
Finally, the beneficial bacteria in your oral microbiome act as the first line of defense against pollen, dust, and other triggers for ear, nose, and throat aggravations by both crowding out the bad guys and producing antimicrobial proteins that can knock out unwanted bacteria before they have a chance to cause trouble.12
But if they're depleted by over-the-top oral hygiene practices, stress, exposure to pollutants, or even spending too much time indoors, they become less able to fight the bad guys, which could mean your system doesn’t have the defenses it needs to keep you well.
How to Support Your Oral Microbiome
Clearly, your mouth microbes do a lot for you. So how can you take care of them in return? It's relatively straightforward: choose a microbe-friendly diet and lifestyle and avoid using products that upend the balance of your microbiome.
A couple of things to put on the "avoid" list include conventional toothpastes (especially those containing triclosan or other antibacterial ingredients), mouthwashes that contain alcohol, sugar, or other bacteria-unfriendly ingredients, and sugary gums or lozenges. Remember, the bad guys in your mouth thrive on sugar, so the more you can avoid it, the better. If you have to use a sweetener, try xylitol instead: it's sweet, so the inhospitable bacteria in your mouth are attracted to it, but it doesn't contain the same molecular components as sugar, which means that the bacteria trying to use it for energy end up starving!13
Once you've gotten rid of potentially damaging products, replace them with natural oral health products, like Hyperbiotics Activated Charcoal Probiotic Toothpaste and bacteria-friendly mouthwash. Even better, give your good guys a boost with a premium oral probiotic like PRO-Dental, which contains several strains of S. Salivarius and L. paracasei shown to effectively crowd out unwanted bacteria, including S. mutans. If you have kids, make sure to teach them healthy brushing habits and give their immune systems full support with PRO-Kids ENT, specifically designed to build up their oral and ENT micro biomes.
As you can see, the oral microbiome has a far greater impact than simply promoting healthy teeth and gums. Research continues to uncover the true ramifications of oral health, but one thing is already abundantly clear: if you take care of the good guys in your mouth, they'll return the favor, and then some.
1. Dewhirst, F.E, Chen, T., Izard, J., Paster, B.J., Tanner, A.C.R. . . . Wade, W.G. (2010). The Human Oral Microbiome. Journal of Bacteriology, 192(19). doi: 10.1128/JB.00542-10
2. Dortbudak, O., Eberhardt, R., Ulm, M., & Persson, G. R. (2005). Periodontitis, a marker of risk in pregnancy for preterm birth. Journal of Clinical Periodontology, 32(1), 45-52.
3. Aagaard, K., Ma, J., Antony, K. M., Ganu, R., Petrosino, J., & Versalovic, J. (2014). The Placenta Harbors a Unique Microbiome. Science Translational Medicine, 6(237).
4.Hajishengallis, G. (2014). The inflammophilic character of the periodontitis-associated microbiota. Molecular Oral Microbiology, 29(6). doi: 10.1111/omi.12065
5. Shreiner, A.B., Kao, J.Y., Young, V.B. (2015). The Gut Microbiome in Health and in Disease. Current Opinion in Gastroenterology, 31(1). doi: 10.1097/MOG.0000000000000139
6. Kilian, M., Chapple, I.C.L., Hannig, M., Marsh, P.D. . . . Zaura, E. (2016). The Oral Microbiome – An Update for Oral Healthcare Professionals. British Dental Journal, 221. doi: 10.1038/sj.bdj.2016.865
7. Han, Y.W., Wang, X. (2013). Mobile Microbiome: Oral Bacteria in Extra-oral Infections and Inflammation. Journal of Dental Research, 92(6). doi: 10.1177/0022034513487559
8. Doel, J.J., Hector, M.P., Amirtham, C.V., Al-Anzan, L.A. . . .Allaker R.P. (2004). Protective Effect of Salivary Nitrate and Microbial Nitrate Reductase Activity Against Caries. European Journal of Oral Sciences, 112(5). doi: 10.1111/j.1600-0722.2004.00153.x
9. Chapple, I.L.C., Genco, R.J. (2013). Diabetes and Periodontal Diseases: Consensus Report of the Joint EFP/AAP Workshop on Periodontitis and Systemic Diseases. Journal Of Clinical Periodontology. doi: 10.1111/jcpe.12077
10. Shoemark D.K., Allen S.J. (2015). The Microbiome and Disease: Reviewing the Links Between the Oral Microbiome, Aging, and Alzheimer's Disease. Journal of Alzheimer's Disease, 43(3). doi: 10.3233/JAD-141170
11. Tiwari, M. (2011). Science Behind Human Saliva. Journal of Natural Science, Biology and Medicine 2(1). doi: 10.4103/0976-9668.82322
12. Pierro, F. D., Donato, G., Fomia, F., Adami, T., Careddu, D., C., & Albera, R. (2012). Preliminary Pediatric Clinical Evaluation of the Oral Probiotic Streptococcus Salivarius K12 in Preventing Recurrent Pharyngitis and/or Tonsillitis Caused by Streptococcus Pyogenes and Recurrent Acute Otitis Media. International Journal of General Medicine, 2012(5). doi: 10.2147/IJGM.S38859
13. Nayak, P.A., Nayak, U.A., Khandelwal, V. (2014). The Effect of Xylitol on Dental Caries and Oral Flora. Clinical, Cosmetic and Investigational Dentistry, 6. doi: 10.2147/CCIDE.S55761
Rachel Allen is a writer at Hyperbiotics who's absolutely obsessed with learning about how our bodies work. She's fascinated by the latest research on bacteria and the role they play in health, and loves to help others learn about how probiotics can help the body get back in balance. For more ideas on how you can benefit from the power of probiotics and live healthier days, be sure to subscribe to our newsletter. To learn more about how a healthy microbiome can enrich your life, subscribe to our newsletter.