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What Is the Oral Microbiome? How to Balance It to Improve Overall Health

By Jillian Levy, CHHC

October 10, 2020

Original article and page source found here.

The mouth (aka the oral cavity) is considered to be a major gateway to the rest of the body. Oftentimes, what’s happening in the oral microbiome is representative of what’s happening elsewhere in the body.

It’s believed there are between 300 and 700 different microbial species living in the average human’s mouth. According to an article published in the Journal of Oral and Maxillofacial Pathology, the oral microbiome is the second largest microbial community in humans second to the gut, which is often simply called “the microbiome.”

Microbes populating the mouth play an important role in functions such as digestion, metabolism, blood pressure regulation and maintenance of the structure of the teeth.

How can you take care of the community of organisms living in your mouth? As you’ll learn below, practicing the right type of oral hygiene, eating a healthy diet and consuming probiotics are some of the best strategies.

What Is the Oral Microbiome?

What exactly is a “human oral microbiome”? The oral microbiome refers to the hundreds of billions of microorganisms that live inside of the oral cavity (the mouth).

Most of these microorganisms are bacteria, both the “good” types and the “bad,” while some are yeast, viruses and fungi. Examples of microbes that live in the oral cavity include Streptococcus and Corynebacteria species.

As defined by the Human Microbiome Project, the oral cavity has nine sites spanning the inside of the mouth:

  • tongue

  • palate

  • tonsils

  • sub- and supra-gingival plaque on teeth

  • keratinized gingiva

  • buccal mucosa

  • throat

  • saliva

Together these microbes form an “ecosystem” that operates similarly to the human gut.

Each part of the mouth has a unique surface and therefore tends to contain its own array of microbes. For example, the tongue contains a different community from what’s on the gums or teeth, due to how their surfaces sustain the life of different microbes.

Dental plaque and the surface of the tongue are especially dense with microbes. They are considered to be “among the densest microbial habitats on Earth.”

How It Relates to Health

Microbiomes (communities of tiny organisms) actually exist everywhere in nature, and they play an important role in dictating human health and sustaining various ecosystems.

The Human Oral Microbiome Database catalogs the genomes of hundreds of bacterial species found in the human mouth. Within one’s mouth there are some bacteria that contribute to overall health, such as by facilitating digestion, and others that can contribute to problems such as gum disease, infections and potentially even cancer.

Some of the positive roles that microorganisms living in the oral microbiome have include:

  • Carrying out digestive and metabolic processes, which support a normal metabolism — for example, some bacteria participate in nitrate metabolism, which helps support healthy blood pressure

  • Facilitating the process of breaking down foods via saliva and turning nutrients from food into energy

  • Transporting ionic minerals from saliva around the mouth

  • Supporting remineralization of the teeth

  • Carrying oxygen to the gums and soft tissues

  • Fighting infections by protecting us from harmful environmental organisms

  • Preventing oxidative stress and inflammation

  • Removing waste products from the mouth’s surface

Signs of Issues

Certain bacteria, viruses and fungi that populate the oral cavity are linked to health concerns that affect various parts of the body, including some you wouldn’t expect, such as the heart disease and reproductive issues. That’s because some bacteria are capable of making their way from the mouth into other parts of the body, including the blood vessels and gut.

How do you know if you’re experiencing an imbalance in microbes living in your mouth (also called dysbiosis)?

Signs and conditions linked to an unbalanced/unhealthy oral microbiome can include:

  • Increased plaque on the teeth that is thick, sticky, smelly and off-white (it can form a film on your teeth in the morning)

  • Bad breath

  • Bleeding gums and receding gums

  • Sensitive teeth

  • Mouth ulcers

  • Oral thrush, or oral candidiasis, is a fungal condition in which candida fungus (usually C. albicans) overgrows

  • Gum disease (periodontitis)

  • Cavities and tooth decay (caries)

  • Endodontic infections (root canal) and alveolar osteitis (dry socket)

  • Tonsillitis

  • Respiratory infections

  • Heart disease and stroke

  • Certain types of cancer

How do cavities relate to your microbiome?

Many people are under the impression that certain harmful bacteria cause cavities, but it’s now understood that the causes of tooth decay, cavities and gum disease, such as gingivitis, are actually related to imbalances in the oral microbiome, rather than the presence of bacteria itself. In other words, certain “pathogenic” bacteria won’t cause problems for someone who has an overall healthy microbiome — however they can trigger disease in others who lack enough healthy bacteria to counteract the pathogens’ effects.

Experts now believe that when the microbiome shifts from being composed of mostly aerobic bacteria to more anaerobic bacteria (such as Streptococcus mutans and Porphymonas gingervali), this creates a hypertrophic biofilm inside the mouth, which makes tooth erosion and gum disease more likely to develop.

Why is there a connection between the oral microbiome and cancer?

Oral cancer is thought to develop in part due to the effects of harmful bacteria in the mouth. Some studies suggest that a common type of mouth bacterium known as Fusobacterium nucleatum may also be involved in the development of colon cancer.

This type of bacteria seems capable of penetrating the cheeks and invading the immune system, most of which is located in the gastrointestinal tract. By contributing to inflammation and free radical damage, bacteria like Fusobacterium nucleatum may play a role in the development of cancer.

How to Balance Oral Microbiome

Maintaining homeostasis in the oral microbiome can help prevent some types of bacteria and microbes from “behaving badly” and contributing to disease.

Wondering, “How can I improve my oral microbiome?” Here are steps you can take to help improve the health of your second largest microbiome:

1. Practice Smart Oral Hygiene

While cleaning the inside of the mouth too much can actually contribute to problems, proper “interdental cleansing”— which includes flossing, brushing with natural toothpaste and sometimes the use of picks — is thought to help support balance within the oral environment.

Certain harsh products used in the mouth, such as some toothpastes and mouthwashes, can eliminate beneficial bacteria in the mouth, contributing to dysfunction of the microbiome. Experts recommend avoiding products such as detergent-based toothpastes and alcohol-containing/antiseptic mouthwashes, including those that are made with these questionable ingredients:

  • Sodium laurel sulfate (SLS)

  • Sodium fluoride

  • Triclosan

  • Artificial sweeteners (such as sodium saccharin, aspartame, xylitol and erythritol)

  • Artificial color dyes (often made from coal tar)

  • Propylene glycol

  • Diethanolamine (DEA)

  • Microbeads (tiny solid plastic particles)

2. Consume Probiotics

Probiotic supplements and foods can help populate the mouth with friendly bacteria, much in the same way as how they support gut health. They work by creating a protective biofilm that supports the health of teeth and gums and reduce inflammation, while blocking bad bacteria from reaching enamel or vulnerable tissues.

They may also help alter the pH of the mouth to stop cavity growth and improve saliva quality to support remineralization of enamel.

What is the best oral probiotic to take? Dentists believe that oral microbiome probiotics are most effective when delivered directly to the mouth in lozenge, milk or chewable form.

Oral microbiome probiotic strains considered most beneficial to oral health (which should be taken for at least two to three months) include:

  • Lactobacillus salivarius

  • L. reuteri

  • Streptococcus salivarius K12 and M18

  • L. sakei

  • L. brevis

  • L. acidophilus

  • L. rhamnosus

  • L. reuteri

  • L. casei

  • Bifidobacillus