Is Your Mouth Affecting Your Brain?

Our bodies contain many bacterial communities that live and grow in various niches, such as the gut, the urinary tract, the surface of the skin as well as the oral cavity.

These communities are termed the microbiome.

We have an agreement in place with these microbes, we host and feed them, and in return they work for us by producing vitamins, supporting the immune system, digesting our food and producing neurotransmitters to keep our brains healthy.

Most people are aware of the gut microbiome, but the mouth is also an especially important host for many microbes which play a critical role in keeping our gums and teeth healthy. As we age, we naturally lose some of the more important protective species in the mouth, which can then lead to the growth of undesirable microbes, some of which will trigger an inflammatory response within the mouth.

For years now, scientists have recognised that cognitive decline including conditions such as Alzheimer’s disease result from inflammatory processes in the brain. More recently though, research has shown a direct link between certain oral bacteria and brain health and specifically Alzheimer’s (AD) and Parkinson’s disease.

Scientists found that bleeding gums, tooth loss and periodontal issues were associated with worse cognitive function. Certain microbes were linked as being more problematic.

The Blood Brain Barrier (BBB) is a semi-permeable membrane that protects the brain from toxins and infection while selectively allowing critical nutrients to enter the brain. In some cases of inflammation, this barrier can become “leaky” allowing microbes to cross into the brain that should never be found there. One troublemaker, Porphyromonas gingivalis, is known to cause gum disease but has also been found to colonise the brains of people with AD.

What happens in the oral cavity, is strongly linked with body health, including brain functioning. This is one of the reasons we now test the oral microbiomes of all our patients with cognitive decline.

What is more interesting is that it isn’t only infection that affects brain health. Certain microbes play a role in signalling directly to the neurotransmitter pathways in the brain that increase brain-derived neurotropic factor which directly stimulates the growth of new nerve cells.

‍

What affects our oral microbiome?

Environmental disruptions such as antibiotic use, mouthwashes or smoking can dramatically affect oral health by affecting the microbial ecosystem in the mouth. This can lead to periodontitis and subsequently affect overall health.

In one study, investigators found that smokers harboured more harmful bacteria in the mouth than non-smokers. This happens primarily because the good populations of microbes are also wiped out, leaving the mouth vulnerable to more aggressive, harmful species. Saliva samples and MRI scans from 60 individuals showed a marked influence of smoking on neurologicalsignalling and this correlated with changes in the oral microbiome. Bottom line - smoking can affect brain health indirectly through impacting changes in the oral microbiome.

What can you do to keep the oral microbiome healthy?

Oral hygiene Oral hygiene is probably the most important thing you can do to keep the mouth healthy, but perhaps not in the way that you have been told. Many of the harsh dental products that we use create further harm to our dental microbes, perpetuating the disruption to this sensitive ecosystem.  Mouth washes, by killing bacteria, will initially help by clearing out those pesky microbes that cause bad breath. But they erode the good bacteria too, leading to a more imbalanced microbiome in the long-run.

Here are some of the simple things that you can do to keep the oral cavity healthy:

• If you are diabetic, keeping blood sugar levels stable and well-managed is important.  Oral bacteria are disturbed not only by sugary foods that we eat, but also by blood glucose levels

• Quit smoking. The importance of giving up smoking has further justification when it comes to mouth bacteria. Smoking harms the delicate balance of oral microorganisms; another great reason to put out that cigarette
• Eliminate sugar. Sugar impacts the oral bacteria, encouraging the growth of acid-loving bacteria which contribute towards inhibiting good bacteria and the subsequent development of periodontal disease
• Avoid acidic drinks. Acidic drinks again encourage the growth of problematic bacteria, even when they are sugar free. This includes all carbonated drinks as well as orange juice
• Interdental brushes can help to reduce the growth of colonies of plaque.  This could be combined with a toothpaste that supports the oral microbiome, such as Zendium

What to do if you have periodontal disease or bad breath?

• Keep regular hygienist appointments
• Considerusing Dentalcidin, a powerful antimicrobial for the mouth that does not affect the good microbes.  Use a tiny amount of the Dentalicidin on interdental brushes to get deep into the gum pockets between teeth
• Follow on after cleaning with an oral probiotic lozenge that recolonises good bacteria
• Consideroral microbiome testing (Invivo Laboratories) to track and monitor progress

‍

If you arealready suffering from cognitive decline, do not wait to get tested. If detected early, cognitive decline due to oral dysbiosis is easily treatable. Given all the good things that our microbes do for us, and with so many simple ways to boost the growth of good bacteria in our mouths within our reach, it is time to act.

‍

References:

Luca Vigano.,et al. “The Oral Microbiome in the Context of Aging and CognitiveImpairment”. Acta Scientific Microbiology 1.8 (2018): 17-22.

Shoemark DK andAllen SJ. “The Microbiome and Disease: Reviewing theLinks between the OralMicrobiome, Aging,and Alzheimer’s Disease”. Journal of Alzheimer’s Disease 43.3(2015) 725-738.

Aragón F., etal. “A Oral health in Alzheimer’s disease: a multicenter case-controlstudy”. Clinical Oral Investigations (2018).

FriedlanderAH., et al. “Alzheimer’s disease Psychopathology, medical management anddental implications” JADA 137.9 (2006): 1240-1251.

SudhakaraP., et al. “Oral Dysbiotic Communities and Their Implications in SystemicDiseases”. Dentistry Journal 6 (2018): 10.

OlsenI and Singhrao SK. “Can oral infection be a risk factor for Alzheimer’sdisease?”. Journal of Oral Microbiology 7 (2015): 29143.

SparksSteina P., et al. “Serum antibodies to periodontal pathogens are a riskfactor for Alzheimer’s disease”. Alzheimers Dement 8.3 (2012): 196-203.

PritchardAB., et al. “Periodontitis, Microbiomes and their Role in Alzheimer’sDisease”. Front Aging Neurosci 9 (2017): 336

HardingA., et al. “Exploring the Association between Alzheimer’s Disease, OralHealth, Microbial Endocrinology and Nutrition”. Front Aging Neurosci 9(2017): 398.

NobleJM et al. “Periodontitis is associated with cognitive impairment amongolder adults: analysis of NHANES-III”. Journal of Neurology, Neurosurgery,and Psychiatry 80.11 (2009):1206-1211.

StewartR., et al. “Associations Between Oral Health and Risk of Dementia in a37-Year Follow-Up Study: The Prospective Population Study of Women inGothenburg”. Journal of the American Geriatrics Society 63.1 (2015):100-105.

Noble JM., et al. “Serum IgG Antibody Levels to Periodontal Microbiota AreAssociated with Incident Alzheimer Disease”. PLoS One 9.12 (2014):e114959.

SochockaM et al. “Association between Periodontal Health Status and CognitiveAbilities. The Role of Cytokine Profile

andSystemic Inflammation”. Current Alzheimer Research 14.9(2017): 978-990.

‍