Good oral hygiene isn’t just for the mouth: It benefits brain health too

02/12/2020 / By Evangelyn Rodriguez

Heart disease and cerebrovascular diseases (e.g., stroke) are the leading causes of death in western countries. These diseases are caused by several factors, such as hypertension, high blood cholesterol, diabetes mellitus, smoking and obesity. However, recent studies have found that there is another unexpected contributor to the development of atherosclerosis and atherothrombosis (blood clot formation): inflammation caused by bacterial infection.

In a study published in the Journal of the American Heart Association, researchers from Tampere University in Finland investigated the presence of oral bacterial DNA in the thrombus aspirates of patients with acute ischemic stroke treated with mechanical thrombectomy. Thrombectomy is a procedure used for the removal of a thrombus or blood clot inside an artery. The researchers found oral streptococcal bacteria in more than half of the samples they tested, suggesting that these microorganisms may play a role in the progression of cerebrovascular diseases, as well as thrombotic events.

The connection between oral health, heart health and brain health

According to a study by Indian researchers, severe periodontitis — inflammation of the gums caused by bacteria — is a stronger risk factor for ischemic stroke than hypertension and smoking. Another study found that the disease also increases the risk of stroke in middle-aged men. When scientists looked at the levels of C-reactive protein (CRP), a marker of inflammation, they found a correlation with the incidence of cardiovascular events and stroke. In fact, inflammation of atherosclerotic plaque affects plaque growth and contributes to plaque rupture, the main cause of thrombosis.

In their previous study, the Finnish researchers reported the presence of DNA from the viridans streptococci group in the thrombus aspirates of heart attack patients. These bacteria can cause infective endocarditis (infection of the heart chambers’ inner lining) and thrombosis. The researchers also found that the amount of streptococcal DNA in the patients’ thrombus samples was higher than the amount present in their blood samples.

When they looked at ruptured and non-ruptured cerebral aneurysm samples as well as thrombus aspirates from patients with lower limb vascular disorders, the researchers detected the presence of the same oral bacteria. This led them to hypothesize that oral bacterial DNA can be found in the cerebral arterial thrombi of stroke patients.

To test their hypothesis, the researchers took thrombus and arterial blood samples from 75 patients and used quantitative polymerase chain reaction to confirm the presence of viridans streptococci, mainly Streptococcus mitis, as well as Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. S. mitis is a known inhabitant of the human mouth. P. gingivalis is involved in periodontitis, while A. actinomycetemcomitans is associated with localized aggressive periodontitis.

The researchers detected bacterial DNA in 84 percent of the thrombus samples. DNA from the S. mitis group was present in 79 percent of the samples. The researchers also found that the amount of Streptococcus species DNA in the samples was 5.10-fold higher than the amount found in the control blood samples from the same patients. On the other hand, all thrombi tested negative for P. gingivalis and A. actinomycetemcomitans.

Based on these results, the researchers concluded that oral streptococcal bacteria contribute to the progression and thrombotic events associated with cerebrovascular diseases. (Related: Brush your teeth every day to keep brain disease away: Study links gingivitis bacteria to increased risk of Alzheimer’s.)

Natural ways to maintain good oral health

The health of your mouth is a good indication of your physical health. Your oral cavity is one of the first to show signs of poor nutrition, infection and systemic diseases. Oral problems, on the other hand, are not only painful and embarrassing, but they can also affect your everyday activities. To avoid these, here are some tips on how to keep your mouth healthy naturally. (h/t to Earth911.com)