Brushing twice a day, flossing every day, and seeing your dentist a couple times a year always made oral health sense. And, we already knew that chronic infections were a risk factor for heart disease and stroke and that one’s dental well-being was connected to one’s overall health. So, in the spring of 2019 when the Journal of the American Heart Association published the first study to ever show the presence of oral bacteria in brain blood clots, we shouldn’t have been shocked. But when 84% of stroke victims have streptococcal bacteria (oral bacteria) show up in aspired thrombi (brain blood clots), the data slaps you across the face as if to say, “Wake up.”
The research group from Finland who announced the new findings has been collecting data for 10 years. The study looked for bacteria in blood clots removed from 75 patients who were treated for an ischemic stroke—a blockage in a blood vessel in the brain—over a recent four-year period. Ischemic stroke accounts for about 87% of all strokes. The study found that 63 of the people studied had bacterial DNA in their blood clot. Specifically, 59 had a strain commonly found in the mouth known to cause infections if it gets into the bloodstream.
Researchers have long known that high blood pressure, high cholesterol, physical inactivity, diabetes, smoking and obesity are risk factors for heart disease and stroke. Systematic reviews of medical literature had already investigated the potential link between oral health and acquired brain injury. As recently as 2018, studies showed a high correlation, but correlation is not causation. In fact, back in 2012, an expert panel of the American Heart Association said there was at that time not enough evidence to show gum disease caused by bacteria was a direct cause of heart disease or stroke. Therefore, the panel added it was not known whether treating gum disease would prevent heart disease.
The work of the Finnish team has helped put a finish to that notion.
Improving oral health to reduce risk of stroke
There’s no magic bullet here. Rather, preventing gum disease comes back to old-fashioned mouth hygiene: brushing and flossing regularly, and visiting your dentist regularly to get a thorough cleaning and dental exam. Most dentists recommend X-rays once a year, too. These are the simple actions one can take to stay ahead of periodontal disease and to keep bacteria at bay.
Then there’s the trickier stuff you can do.
What ought not to get lost in this new understanding of the connection between bacteria and brain blood clots is the older understanding of how smoking is related to heart disease and stroke.
The Maryland Department of Health puts it this way:
“Smoking weakens your body’s immune system. This makes it harder to fight off a gum infection. Once you have gum damage, smoking also makes it harder for your gums to heal.
Nicotine in tobacco causes blood vessels to constrict. As vessels narrow, blood pressure rises.
Undetected or uncontrolled high blood pressure leads to heart disease, stroke, kidney failure and premature death. Quitting smoking and maintaining a healthy blood pressure through diet, exercise and nutrition may reduce the risk of developing heart disease and stroke. Additional research needs to be conducted on the relationship between oral health and heart disease and stroke. However, it is important to note that people with good oral health generally have fewer chronic diseases, including heart disease and stroke.”
Put another way, that old adage “You are what you eat” has a parentheses: “You are what you eat (and smoke). And that means—if you haven’t already—you need to take a serious look at more than how well you clean your mouth. You also need to look at what you’re putting into it. We dentists aren’t the nutritionists or psychologists you may need to tap for help with that, but we can certainly support your efforts to make positive change. It starts with your next visit.