Videos circulating on social media warn that using mouthwash may increase the risk of high blood pressure and harm heart health because it eliminates the "beneficial" bacteria in the mouth.
Although this message may seem frightening, the truth is more complex than these short clips show, and it does not warrant getting rid of mouthwash permanently.
Our mouths contain more than 700 types of bacteria, found on the hard surfaces of the teeth and in the soft tissues of the oral mucosa, which together form a balanced microbiome. These bacteria help prevent the growth of harmful bacteria, support normal bodily functions, and contribute to the health of the mouth and the body in general.
One of the most important roles of these bacteria is to convert the "nitrates" found in food, especially leafy green vegetables, into "nitrites".
When we ingest nitrite, the body converts it into nitric oxide, a substance that plays a vital role in regulating blood pressure and supporting brain and muscle function. Therefore, anything that affects beneficial bacteria may affect nitric oxide production.
Several small studies have found that using mouthwash can alter the balance of bacteria in the mouth, reducing its ability to convert nitrates into nitrites.
In a study involving 19 healthy volunteers, the use of a wash containing "chlorhexidine" for seven days resulted in a slight increase in blood pressure and a decrease in nitrite levels.
Another study of 27 healthy adults reported that rinsing twice daily with a strong mouthwash for a week significantly increased blood pressure.
In a third trial involving 15 adults already suffering from high blood pressure, using the same type of wash for three days increased their blood pressure.
However, an important detail often overlooked in these videos is that most of these studies used a strong type of mouthwash called chlorhexidine. This type is not for everyday use; it is typically prescribed for gum disease or after oral surgery and is only recommended for short-term use. This means the results may not apply to the milder mouthwashes that most people buy from stores.
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Another study, conducted on 12 adults, compared the effects of three types of mouthwash. It found that water and a mild, non-abrasive mouthwash caused the natural conversion of nitrates to nitrites, while a mouthwash containing cetylpyridinium chloride (a potent antibacterial compound) partially prevented the conversion, and chlorhexidine (the strongest) almost completely stopped it. The stronger types of mouthwash were also associated with an increase in systolic blood pressure
Alcohol is another common ingredient in many mouthwashes, and as an antimicrobial agent, it may affect oral bacteria. Some studies have suggested a possible link between alcohol-based mouthwashes and an increased risk of oral cancer, but there is insufficient research on its direct effects on heart health.
In contrast, long-term studies suggest a different outcome. A 19-year study of 354 adults found that good oral hygiene, such as brushing and flossing, was associated with a reduced risk of death from heart disease. However, regular use of mouthwash, whether mild or strong, showed no effect on heart health. This includes mild mouthwashes containing fluoride and alcohol, as well as strong mouthwashes like chlorhexidine
Ultimately, the type of mouthwash is very important. Stronger types, such as chlorhexidine, can disrupt beneficial bacteria if used for extended periods, so they are reserved for short-term use only when needed by patients with gum disease or oral infections. Milder, alcohol-free mouthwashes or those with gentler ingredients appear to be safer and do not significantly affect nitrate conversion or blood pressure.
However, even mild mouthwashes require attention to their ingredients, as even alcohol-free options may contain antibacterial agents such as cetylpyridinium chloride. Therefore, it's best to choose a mouthwash that suits your needs and use it sparingly, remembering that basic oral hygiene—brushing, flossing, and regular dental checkups—remains far more important than relying solely on mouthwash
