Social media videos are circulating alarming claims that using mouthwash can elevate the risk of high blood pressure and heart disease by eliminating beneficial oral bacteria crucial for cardiovascular health. However, an expert clarifies that the reality is considerably more nuanced and complex than these viral assertions suggest.
The Role of Oral Bacteria in Cardiovascular Health
Our mouths host a diverse community of bacteria that play vital roles in preventing disease, supporting normal bodily functions, and promoting overall health. Joanna L'Heureux, a Postdoctoral Researcher in Public Health and Sport Sciences at the University of Exeter, explains one critical function: "One of the important roles these oral bacteria have is converting the nitrate in our food—typically from sources like leafy greens—into nitrite. When we swallow nitrite, the body transforms it into nitric oxide." She emphasizes, "This is a prime example of how bacteria contribute to maintaining bodily health."
Nitric oxide is essential for regulating blood pressure and supporting brain and muscle function, making the oral microbiome's role in its production significant for cardiovascular well-being.
How Different Mouthwashes Affect Oral Bacteria
Joanna notes that several small studies have demonstrated that mouthwash can alter the balance of bacteria in the mouth. This disruption may impair the bacteria's ability to convert dietary nitrate into nitrite, thereby reducing the body's production of nitric oxide. However, she highlights a crucial detail often omitted from social media videos: the specific type of mouthwash used in these studies.
Many studies linking mouthwash use to blood pressure changes involved participants using chlorhexidine. This is a potent over-the-counter antiseptic mouthwash recommended only for short-term use in individuals with gum disease or following dental procedures, where its antimicrobial properties are beneficial. Chlorhexidine disrupts oral bacteria to aid infection control, including the bacteria responsible for nitrate-to-nitrite conversion. This makes it an ideal choice for researchers studying the nitrate-nitrite-nitric oxide pathway, but it also means the findings may not apply to milder, everyday mouthwashes.
Evidence from Clinical Trials
A trial involving 12 healthy adults examined the effects of three different mouthwashes—along with gargling water as a control—on oral bacteria. After consuming a nitrate-rich juice, researchers measured how much nitrate was converted to nitrite by oral bacteria. Water and a mild mouthwash without harsh ingredients like chlorhexidine produced a typical response, with nitrate successfully converted into nitrite.
In contrast, a mouthwash containing cetylpyridinium chloride, which also has strong antibacterial effects, partially blocked this conversion. The most potent chlorhexidine mouthwash nearly halted the process entirely, consistent with its robust antimicrobial properties. These stronger mouthwashes were also associated with higher systolic blood pressure readings.
Alcohol (ethanol) is another common ingredient in many mouthwashes and, as an antimicrobial, may influence the oral microbiome. However, Joanna points out, "There are currently no studies that have specifically examined the effects of ethanol-only mouth rinses on the oral microbiome or cardiovascular health."
Choosing the Right Mouthwash for Your Health
Overall, evidence indicates that mild, over-the-counter mouthwashes—the type most people purchase—are less likely to significantly interfere with nitrate-to-nitrite conversion or affect blood pressure. Joanna advises, "Together, these studies suggest that some types of mouthwash, such as chlorhexidine, disrupt beneficial oral bacteria and the nitrate-nitrite-nitric oxide pathway when used long term. But more research is needed to fully understand the long-term effects of other mouthwash types on cardiovascular health, including mild everyday brands and those containing alcohol."
Mouthwashes vary widely in formulation and purpose, so it is essential to check the active ingredients on the packaging. Alcohol-free and milder options appear to have less impact on heart-healthy bacteria compared to stronger varieties. However, even alcohol-free mouthwashes can contain antibacterial agents like cetylpyridinium chloride, so careful ingredient scrutiny is advised. Strong mouthwashes with chlorhexidine are best reserved for addressing gum disease or oral infections.
The Broader Context of Oral and Heart Health
It is also important to recognize that poor oral health and untreated infections can contribute to heart disease more broadly. For instance, a systematic review of 82 studies concluded that chronic oral disease and tooth loss were associated with an increased risk of heart problems. This underscores why maintaining a healthy balance of mouth bacteria matters beyond dental health alone.
To safeguard both oral and overall health, maintain consistent brushing and flossing routines, schedule regular dental visits, and select a mouthwash that aligns with your specific needs, using it in moderation.
