Can oral bacteria cause Alzheimer’s disease?
If you have poor oral hygiene then you are probably at a higher risk of a number of oral health issues such as plaque, tartar, tooth decay, cavities and chronic gum disease (periodontal disease). That’s because inadequate oral hygiene opens the door to potentially hundreds of pathogenic oral bacteria to your teeth and gums.
Other health consequences
Oral health issues may be only one of the consequences of allowing pathogenic oral bacteria to develop in your oral cavity. A number of clinical studies in recent years have established links between certain species of oral bacteria and Alzheimer’s disease.
These oral bacteria have the ability to migrate to and colonise your brain tissue. The three main culprits identified so far are Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. Check them out (in order) the top image:
These nasty little critters can infiltrate and infect your gums and even your jawbone – like termites in wood. Additionally, these bacteria can travel around your body and enter your brain on a regular basis.
Oral bacteria that can crawl their way into your brain
In 2014, UK scientists were first able to identify the presence of the three oral bacteria (listed above) in the brain tissue of living Alzheimer’s patients. The researchers established that at least two of the bacteria – once firmly established in the oral cavity – had the ability and versatility to enter the brain via two different pathways.
The first pathway was via the blood stream where they could attach to red blood cells, and travel directly into the brain – where they get off because there are no immune checkpoints. What this means for patients with bleeding gums, is that every time they brush their teeth or eat food, a fresh influx of bacteria can enter the bloodstream and reach the brain in a matter of seconds.
The second pathway came as a surprise to the UK researchers. Since the bacteria are motile (capable of motion), they were able to “crawl” their way to the brain via the nerves that connect tooth roots to the brain – a short distance of a several centimetres.
Only Alzheimer’s patients had the oral bacteria present in their brains
When the UK scientists tested non-Alzheimer’s patients for the bacteria, they discovered that none had the suspect bacteria present in their brain tissue, whereas all of the patients with the disease did.
How might oral bacteria trigger the onset of Alzheimer’s?
More studies need to be conducted to find a causative link between the suspect bacteria and Alzheimer’s disease. However, the UK researchers are working with the theory that if the brain is exposed repeatedly to these oral bacteria and their by-products, the subsequent immune response may result in death of neurons in the brain area associated with memory, as well as nerve cell death.
How can pathogenic oral bacteria be identified & eliminated from your body?
At present, the diagnosis and treatment of pathogenic oral bacteria can only be performed via an oral bacteria DNA test and anti-biotic treatment. Root planing, a dental treatment used to deep clean between the teeth and gums, is a treatment method that can only remove the plaque and calculus in those areas.
Singhrao, S. K., Harding, A., Poole, S., Kesavalu, L., & Crean, S. (2015). Porphyromonas gingivalis Periodontal Infection and Its Putative Links with Alzheimer’s Disease. Mediators of inflammation, 2015, 137357.
Poole, S., Singhrao, S. K., & Crean, S. J. (2014). Emerging evidence for associations between periodontitis and the development of Alzheimer’s disease. Faculty Dental Journal, 5(1), 38-42. doi:10.1308/204268514×13859766312719