Research suggests that there may be an association between an unhealthy oral microbiome and adverse effects on the cardiovascular system. Specifically, poor dental hygiene practices, periodontal disease, dental caries, or tooth loss may be associated with an increased risk of cardiovascular disease. Daily brushing, flossing, and annual dental examinations support optimal oral health and may potentially promote heart health. However, could twice-daily mouthwash also play a role?

Unmasking the potential hidden risks of mouthwash 

Over-the-counter (OTC) mouthwashes are commonly used to freshen breath or leave a pleasant taste. Most contain antibacterial ingredients, such as chlorhexidine, triclosan, cetylpyridinium chloride, alcohol, essential oils, fluoride, and peroxide. Depending on the concentration, these ingredients may be either bacteriostatic or bactericidal. They target a broad spectrum of bacteria rather than specific pathogens. Cosmetic mouthwashes offer only temporary benefits with no known chemical or biological applications beyond freshness. While antibacterial mouthwashes may support those with dental plaque or gingivitis, their effectiveness against severe forms of periodontal disease and dental caries is unclear. 

The oral microbiome comprises over 700 bacterial species. In addition to targeting pathogenic bacteria, mouthwashes may harm beneficial commensal bacteria vital for local and systemic health. One of the major roles of commensal oral bacteria for systemic health is supporting healthy nitric oxide (NO) production and bioavailability. 

Nitric oxide is needed for normal blood pressure and circulation. During what is known as the “enterosalivary pathway,” the body is able to convert dietary intake of nitrates from food or supplements into NO. However, a crucial step in the enterosalivary pathway requires a healthy oral microbiome, allowing the reduction of salivary nitrate to nitrite by nitrate reductases found in certain commensal oral bacteria. Even with ample dietary nitrate intake, this pathway can only proceed with the presence of these commensal oral bacteria. Although the body has an alternative NO production pathway (endogenously in the endothelium), this pathway may be insufficient in certain individuals due to increased age, cardiovascular health conditions, or endothelial dysfunction.

The silent microbiome destroyer 

An in vitro study shows that mouthwashes containing 0.12% chlorhexidine may destroy over 90% of the oral-nitrate-reducing bacteria, leading to an 85% reduction in reduced nitrate. Several small clinical studies have observed an association between frequent mouthwash use (containing chlorhexidine or alcohol-free mouthwash) with increased blood pressure and decreased nitrite levels. 

A longitudinal 3-year study (n = 1,206) observed that participants who used OTC mouthwash more than twice daily at baseline had a 55% significantly elevated risk of prediabetes and diabetes compared to less frequent users and non-mouthwash users. Interestingly, mouthwash use less than twice daily had no association, suggesting a potential threshold effect. However, the study lacked details on mouthwash types or antibacterial agents, necessitating further investigation.

Conclusion and other related articles 

Current research suggests that indiscriminate use of antibacterial mouthwashes may cause more harm than good regarding heart health, as it may disrupt the oral microbiome and healthy NO production and bioavailability. However, further research is needed to draw definitive conclusions.   

Learn more about the growing connection between the oral microbiome and cardiovascular health 

Find out how the oral microbiome is necessary for healthy NO status and blood pressure 

Explore the dual pathways and nutrients needed for enhanced NO production 

By Danielle Moyer Male, MS, CNS, LDN