Oral Health and the Oral Microbiome - AP Nutritional Therapy
Oral Health and the Oral Microbiome

by Alissa Powell

Did you know poor oral health has been linked to colorectal cancer?

The Oral Microbiome and Disease

There is a lot of research and information about the gut microbiome – the collection of bacteria and other microorganisms that live in our gut which amongst many other roles, helps to protect us from foreign invaders and keep us healthy. Did you know that microbiomes exist in other areas of the body as well, including the vagina, skin, lungs, and in our mouths?

The oral microbiome is second to the gut in terms of size and variety of the microbiota, containing over 700 species of bacteria. The bacteria colonise both the hard surfaces (teeth) as well as the soft tissues, including the tongue, cheeks, tonsils, hard and soft palates, and more. The oral microbiome helps to maintain not just our oral health, but the health of our entire bodies. 1

The mouth is constantly in contact with the outside world both airborne and through food, and thereby exposed continuously to potential pathogens. A balanced oral microbiome is our first line of defence against these potentially harmful substances. Imbalances, or dysbiosis, of the oral microbiome allow pathogens to take hold and cause disease.

When dysbiosis in the oral microbiome exists, it can cause problems in the mouth itself, including overgrowth of plaque, bad breath, bleeding and receding gum, gum disease, tooth sensitivity, ulcers, infections, and more. Some bacteria are capable of migrating to other parts of the body as well, and as the mouth is the entryway to the respiratory and digestive systems, this can have systemic implications. 2

In studies on associations between the oral microbiome and systemic disease, bacteria normally found in the oral cavity have been found in higher amounts in individuals presenting with many other diseases, indicating bacterial migration. These diseases include colorectal cancer, pancreatic cancer, cystic fibrosis, cardiovascular disease, rheumatoid arthritis, Alzheimer’s disease and diabetes. Periodontitis (inflammation of the tissue around the teeth, causing receding gums and loosening teeth) has been linked with many types of cancer, in the oral cavity and in other tissues including the oesophagus, the gut, lungs, pancreas, prostate, and breast. 2

How to Look After your Oral Microbiome

It is important to maintain balance in your oral microbiome to help prevent bacteria and pathogens from contributing to disease. Let’s start with things which can be detrimental to the oral microbiome:

What Not To Do

Consume too much alcohol – alcohol, especially when consumed in large quantities, can alter the composition of the oral microbiome. 3

Smoke – smoking affects the composition and abundance of bacteria in the oral microbiome. 4

Use certain mouthwash – Mouthwash doesn’t differentiate between ‘good’ and ‘bad’ bacteria in the mouth, and so long-term use can cause an imbalance in the oral microbiome. Antiseptic chlorhexidine mouthwash has been found to reduce microbial diversity in the mouth, interfere with the conversion of nitrate into nitrite (a key process for reducing blood pressure), and increase acidity in saliva which can lead to damage of the teeth and mucosa. Brand names include Peridex, Hibiclens, Paroex, Periogard. 5

Eat sugar – Diets high in sugar are linked to tooth decay. In a study of pre-school aged children in Scotland, toothbrushing offered some protection but was insufficient in mediating diet-driven tooth decay. 6

Use products with questionable ingredients – Avoid toothpastes and mouthwashes with sodium laurel sulfate, sodium fluoride, artificial sweeteners, artificial colours, and triclosan.

What you Should Do:

Brush your teeth twice a day – brushing for approximately 2 minutes twice a day with a soft bristled brush – or better yet an electric or battery-operated toothbrush – can effectively reduce plaque and help reduce the occurrence of gum disease. Don’t brush your teeth right after eating, especially if you’ve eaten acidic food. Remember to brush your tongue (and the roof of your mouth) or use a tongue scraper. If you are uncertain of the best tooth brushing technique, ask your dentist or dental hygienist.

Floss – using loose floss or dental picks, be sure to guide the floss between each tooth, curving the floss against the tooth into a C-shape. Again, ask your dental professional for tips if you are uncertain.

Oil pull –used extensively in Ayurvedic practice, swishing and gargling oil (particularly coconut oil or sesame oil) can have systemic health benefits. Ayurveda believes that each section of the tongue is connected to other organs of the body (similar to reflexology and Traditional Chinese Medicine). Coconut oil is anti-inflammatory and antimicrobial and can help promote a balanced and healthy oral microbiome. 7

How to oil pull? I recommend keeping a small pot of extra virgin (raw) coconut oil, a teaspoon, and a paper cup in your shower. When you start your shower, place a heaping teaspoon of oil in your mouth and let it dissolve. ‘Pull’ it through your teeth forcefully, and swish it around your mouth for the duration of your shower. When done, spit the used oil into the cup. Dispose of the used oil after you fill the cup. Do not spit the oil down the drain as coconut oil hardens at room temperature and will clog your pipes. (Alternatively, keep swishing as you get dressed and spit the contents into your bin.)

Take an oral probiotic – look for probiotics which are in lozenge, drink, or chewable form, and which specifically state they contain strains beneficial to the oral microbiome.

Eat a diverse, healthy diet – consuming a diet rich in nutrients, including green leafy vegetables, colourful fruits, cruciferous vegetables (broccoli, kale, cauliflower, etc), healthy fats, fermented foods, and well-sourced meats will benefit the oral microbiome. Too much sugar, refined carbohydrates, fizzy drinks, and highly processed foods will promote the growth of non-beneficial bacteria and thereby contribute to tooth and gum-related diseases. Remember to drink plenty of water and herbal teas for good oral health.

Tea tree soak – store your toothbrush head in water with a few drops of tea tree oil to kill any remaining bacteria on your brush. Change the water daily. (don’t do this if your brush is plugged into anything)

Breathe through your nose – breathing through your mouth dries the oral cavity and decreases saliva production. Saliva is needed to balance the pH in the mouth and to flush away bacteria. 8

See your dentist and hygienist regularly – even if you do everything you can to promote a healthy mouth, you should still see your dentist regularly.


  1. Deo, P.N. and Deshmukh, R. (2019). “Oral microbiome: Unveiling the fundamentals”, Journal of Oral Maxillofacial Pathology, 23(1), pp. 122-128.
  2. Willis, J.R. and Gabaldon, T. (2020). “The human oral microbiome in health and disease: From sequences to ecosystems”, Microorganisms, 8(2). doi: 10.3390/microorganisms8020308
  3. Fan, X. Peters, B.A. Jacobs, E.J. et al. (2018). “Drinking alcohol is associated with variation in the human oral microbiome in a large study of American adults”, Microbiome, 6(59).  https://doi.org/10.1186/s40168-018-0448-x
  4. Wu, J. Peters, B.A. Dominjanni, C. et al. (2016). “Cigarette smoking and the oral microbiome in a large study of American adults”, The ISME Journal, 10, pp. 2435-2446.
  5. Bescos, R. Ashworth, A. Cutler, C. et al. (2020). “Effects of chlorhexidine mouthwash on the oral microbiome”, Scientific Reports, 10(1). https://doi.org/10.1038/s41598-020-61912-4
  6. Skafida, V. and Chambers, S. (2014). “Dental decay in preschool children in Scotland – associations with diet and oral hygiene practices”, European Journal of Public Health, 24(supp2), pp. 356.
  7. Singh, A. and Purohit, B. (2011). “Tooth brushing, oil pulling and tissue regeneration: A review of holistic approaches to oral health”, Journal of Ayurveda and Integrative Medicine, 2(2), pp. 64-68.
  8. Tamkin, J. (2020). “Impact of airway dysfunction on dental health”, Bioinformation, 16(1), pp. 26-29.