Could dental infection put you at risk of more serious illnesses including Alzheimer's? If so, what are the main risk factors – and how can we reduce the risks?

Could dental infection lead to other health risks?

Gum infection has been linked to an increased risk of diseases such as obesity, type 2 diabetes and gastrointestinal and pancreatic cancers – although how exactly this happens still isn’t clear. That’s the conclusion of a 2015 article in Mediators of Inflammation.  

It had also been suggested that periodontitis (inflammation of the gums) might play a part in the onset of cardiovascular diseases (such as heart attack, angina and stroke). However, the American Heart Association has concluded that there isn’t yet evidence that gum inflammation causes cardiovascular disease.

What are the main risk factors for gum disease?

Despite our best efforts the UK prevalence of chronic periodontitis has remained at 45%. The NHS advises that plaque is a significant cause of gum disease. Plaque is a sticky substance which forms on the teeth when you eat and drink sugary and starchy food in particular. Initially this causes gingivitis (a milder form of gum disease with possible symptoms including bleeding when you brush your teeth and bad breath). If not treated this can lead to periodontitis (more severe, affecting the tissues that support teeth and hold them in place). If untreated this can lead the bone in the jaw to decay and teeth to become loose and eventually fall out.

Is there a link between Gum Disease and Alzheimer's? 

In January 2019, it was reported that bacteria associated with chronic gum disease, Porphyromonas gingivalis, in the brains of people with Alzheimer's. Brain tissue, spinal fluid, and saliva from dead and living patients with diagnosed and suspected Alzheimer's were analysed. Tests on mice confirmed the bacteria could travel from the mouth to the brain and showed the toxic protein they secrete, called gingipain, destroyed brain neurons. The bacteria also increased production of amyloid beta, a component of the amyloid plaques commonly associated with Alzheimer's. 

According to the American Academy of Periodontology other risk factors include:

Smoking - which may be one of the most significant risk factors for developing and encouraging periodontal (gum) disease.

GeneticsResearch indicates that some people may be genetically more susceptible to gum disease.

StressStress is known to make it more difficult for the body to fight off infection, including gum disease.

MediationsSome drugs, such as oral contraceptives, anti-depressants, and certain heart medicines, can affect your oral health. So let your dentist know what medicines you are taking.

Cleaning or Grinding Your Teeth – This  can put excessive force on the supporting tissues of the teeth and speed up their destruction. 

Diabetes, Cardiovascular Disease and Rheumatoid Arthritis - systemic diseases like these, that interfere with the body's inflammatory system, may worsen the condition of the gums.

Poor Poor Nutrition and Obesity - A diet low in important nutrients (such as vitamins and minerals) can compromise the body's immune system and  the body’s ability to fight infection. Because gum disease begins as an infection, poor nutrition can worsen the condition of your gums. Research has also shown that obesity may increase the risk of gum disease.

Do the risksrise as we grow older?

Yes, that’s partly because, as we grow older, our immune systems weaken and become more vulnerable to diseases - including mouth and gum infections.

A non systematic review in 2015 in Clinical Interventions in Ageing suggested a number of reasons why the risk of tooth decay (another dental health problem) rises as we grow older. These included: age-related reductions in the amount of (antibacterial) saliva our mouths produce; a poor diet; medications which reduce saliva as a side effect; and exposure of the root surface by gum recession.

Osteoporosis and periodontal diseases are bone destructive diseases. So it has been suggested that osteoporosis (which is more of a risk as we get older) could also be a risk factor for gum disease, although more research is needed here.

Can bacteria in your mouth get into your bloodstream?

Yes, most commonly this is through the gums. Healthy gums, like healthy skin, keep infection out of your system. However, if you don’t keep your mouth clean,then bacteria begin to grow and your gums become inflamed. Hencethey become a less effective barrier and can let bacteria through.

Bacteria can also get into your bloodstream through your teeth. When dental decay becomes so severe that it gets into the central pulp of the tooth, bacteria can get into the blood vessels in the pulp and from there be carried around the body.  

How to reduce the risk of gum disease?

  • Avoid preventable risks like sugary food, fizzy drinks, smoking and snacking between meals. The more frequently you eat sugary food the greater the problem, because the bacteria that live in your mouth only need a small amount of sugar to make the acid that starts the process of decay and it takes your saliva at least 30 minutes to neutralize the acid.
  • Brush your teeth twice a day but not aggressively (using a fluoride toothpaste to strengthen the enamel on your teeth) and also floss/use an interdental brush nightly – to reduce plaque and bacterial infection.
  • Visit your Dentist and Oral hygienist on a regular basis, to ensure any decay is found and treated before it can get into the pulp (and from there into the bloodstream).
  • Rinse your mouth with salted water. There haven’t been any scientific studies of the benefits of salted water but many dentists recommend this and most patients with infections find it helpful.
  • Or use a mouthwash to help keep your mouth free of harmful bacteria and make the enamel on your teeth more resistant to acid attack. There has been debate as to whether mouthwashes containing alcohol increase the risk of oral cancer and also dry the mouth, reducing the antibacterial effect of saliva, so you may prefer to buy ones without alcohol.
  • Saliva helps counter bacteria, so encourage the flow of saliva by chewing your food well and also chewing sugar free gum after meals. 


  • Gum disease and tooth decay may lead to more serious health conditions – like type 2 diabetes and some cancers.
  • So ensuring good dental health isn’t just good for our teeth and gums – it is good for our overall health.
  • The risk of gum disease increases as we get older, partly because our immune system gets weaker.
  • Other risk factors include sugary food and drink, smoking, stress, some medications, grinding your teeth, poor nutrition, some chronic illnesses (like type 2 diabetes and cardiovascular disease) and obesity.
  • To reduce the risk - avoid sugary food and drink, don’t smoke, eat healthily, maintain a healthy weight and ensure good oral hygiene.  

Reviewed and updated by Kayhan Nouri-Aria, July 2019. Next review date July 2023.