Introduction 

This article unpacks current research linking gum disease with Alzheimer’s. Currently, scientific evidence and clinical studies have offered credible insight into how oral health is connected to your brain health more than we think. Hopefully, by the end of this article, you’ll understand the risks, science, and preventative actions you can take to protect both your gums and brain. 

Emerging evidence has shown a strong link between Periodontal disease and Alzheimer's, with research suggesting that people with chronic gum disease have approximately a 70% higher risk compared to those who have healthy gums.^1,2

Additionally, gum disease is associated with accelerated memory decline, particularly in individuals with present early-stage Alzheimer’s or mild cognitive impairment. 

Oral bacteria like Porphyromonas gingivalis, found in gum disease, can enter the bloodstream and potentially reach the brain.

With more to explore, keep reading to understand the connection between oral health and the brain to safeguard both your gums and memory.

What is periodontal disease?

Periodontal disease, also known as gum disease, is a chronic inflammatory condition that affects the tissue surrounding the teeth. It starts with gingivitis, a disease which is characterised by red, swollen gums which bleed, and progresses into periodontitis. Periodontitis is where the gums start to recede, forming pockets within the gums that are able to become infected and cause damage to the bone and connective tissues.³ 

This condition is primarily caused by poor oral hygiene, allowing plaque, a film of bacteria, to accumulate on the surface of the teeth and harden into tartar. If this is left untreated, periodontal disease can lead to tooth loss and has been increasingly recognised for its role in systemic inflammation and its impact on overall health.⁴

What is alzheimer's disease?

Alzheimer's disease is a progressive neurodegenerative disorder which primarily affects memory and cognitive behaviour. It is one of the most common causes of dementia, which is a syndrome and not a disease like Alzheimer's, and typically starts with memory loss, which eventually advances to severe cognitive impairment and a loss of independence.⁵ 

The main feature of Alzheimer's is the accumulation of amyloid-beta plaque and tau tangles in the brain.⁶ Amyloid-beta plaques are clusters of protein that form in the brain alongside degenerating neurons and other cells in the brain, whereas Tau tangles are filaments which are found to tangle around neurons.⁷ This disrupts regular neuronal signalling and leads to cell death. While age, genetics, and certain lifestyle factors are known contributors, attention has been shifted to risk factors like inflammation and chronic infections, including those originating in the mouth.⁸

The link between periodontal disease and alzheimer’s

Many observational studies have demonstrated that individuals with chronic periodontitis are significantly more likely to develop Alzheimer's disease.⁹ A research database found that patients who have had chronic periodontitis for ten years or more have a 70% increased risk of Alzheimer's. Other studies have detected DNA of oral bacteria, like Porphyromonas gingivalis, in the brains of individuals with Alzheimer's, which suggests that periodontal pathogens can contribute directly to neurodegenerative processes.¹⁰

Inflammation & microbacterial invasion 

The link between Periodontal disease and Alzheimer's is understood through systemic inflammation and microbial invasion. The pathogens in periodontitis release bacterial membrane vesicles, which are small particles that have virulence factors, which help bacteria invade the immune system and damage tissue. These factors include lipopolysaccharides, gingipains, and inflammatory RNAs, all of which trigger immune responses, promote tissue degradation, and drive chronic inflammation, which are linked to diseases like Alzheimer's and periodontitis. 

Unlike whole bacteria, these small, fragmented pieces can enter the bloodstream, cross the blood-brain barrier, and deposit in the brain.¹²

P.ginigivalis vesicles have been found to disrupt proteins in the blood-brain barrier and stimulate neuroinflammatory responses, which increase the expression of proinflammatory cytokines, proteins which signal an immune response, and phosphorylation of tau. When tau is phosphorylated, the process of phosphorylation can change the chemical formation of the protein and cause complications by turning its function on or off. These are both hallmarks seen in Alzheimer's.¹¹

Overall, research supports the idea that chronic oral infections act as a source of neuroinflammation, contributing to the onset and progression of Alzheimer's disease. 

Can treating gum disease reduce the risk of alzheimer’s?

Some studies indicate that treating periodontal disease can lower systemic inflammatory responses in the body and can reduce the risk or progression of Alzheimer's disease. Some interventional studies have indicated that resting periodontal disease can lower systemic inflammation, which is linked with slower cognitive decline.^8,10

Oral care habits 

Practising good oral hygiene is not only about preserving your teeth but also your gums and bodily function. Effective cleaning habits like brushing twice daily, flossing, going for regular dental check-ups and seeing a hygienist can help maintain good oral hygiene. Also, avoiding tobacco and limiting sugar intake also supports healthy gums.

Investing in an electric toothbrush, rather than a manual one, can help with effective cleaning, and coupling this with an antimicrobial mouthwash can be helpful.¹³ Importantly, recognising and treating gum disease in its early stages can prevent further inflammation and reduce the risk of having a systemic effect, especially related to the brain. 

Summary

Scientific research increasingly supports a strong connection between Periodontal disease and Alzheimer's disease, with chronic gum infections being a main contributor to systemic inflammation and microbial invasion of the blood-brain barrier. 

Gum disease is driven by poor oral hygiene and harmful bacteria, like Porphyromonas gingivalis, which can lead to the release of bacterial membrane vesicles that cross the blood-brain barrier and trigger neuroinflammation, which is the key process involved in the pathology of Alzheimer's. Evidence has shown that patients with chronic inflammation of the gums have a 70% higher risk of Alzheimer’s. Thus, it is imperative that one maintains good oral hygiene, significantly lowering the chances of both diseases.