Researchers from the Institute of Tropical Medicine in Antwerp, Belgium, have identified significant changes in the composition and abundance of bacteria in study participants’ oral microbiomes after using a popular brand of alcohol-based mouthwash.
The oral microbiome, the community of bacteria that live in the mouth, plays a crucial role in digesting food and maintaining oral health. The study, published in the Journal of Medical Microbiology, is a follow-up to a larger investigation exploring the use of mouthwash as a method to reduce the transmission of sexually transmitted diseases in men who have sex with men.
The researchers found that two species of opportunistic bacteria, Fusobacterium nucleatum and Streptococcus anginosus, were significantly more abundant in the mouth after three months of daily use of the alcohol-based mouthwash. These two bacteria have been previously linked to gum disease, oesophageal and colorectal cancers. Additionally, the researchers observed a decrease in a group of bacteria called Actinobacteria, which are crucial contributors to the regulation of blood pressure.
Implications for Daily Mouthwash Users
Dr Jolein Laumen, first author of the study and researcher at ITM’s Unit of Sexually Transmitted Infections, cautioned, “Alcohol-based mouthwashes are widely available. The public may use them daily to tackle bad breath or prevent periodontitis, but they should be aware of the potential implications. Ideally, long-term usage should be guided by healthcare professionals”.
Professor Chris Kenyon, an author of the study and Head of the Unit of Sexually Transmitted Infections, added, “Up to half of men who have sex with men report using mouthwash for oral hygiene. This study adds to the literature that this is likely having an adverse effect on their oral microbiomes”.
Limitations and Future Research
While the results link the daily use of alcohol-based mouthwash to alterations of the oral microbiome, the researchers are reluctant to draw substantial conclusions from the data. Information on dietary habits and smoking was not collected, so researchers were unable to account for this in the analysis. Additionally, as the small sample group was taken from the initial study, the results of this study may not be representative of the population as a whole.
Further research should examine how the detected changes affect clinical outcomes on larger and more representative sample groups. This will help to better understand the potential long-term effects of daily alcohol-based mouthwash use on oral health and overall well-being.
As the public continues to use alcohol-based mouthwashes for oral hygiene, it is essential to raise awareness about the potential implications of long-term use. Healthcare professionals should guide patients in making informed decisions about their oral care routines, taking into account the latest research findings. While this study raises important questions about the impact of alcohol-based mouthwash on the oral microbiome, more comprehensive research is needed to fully understand the risks and benefits associated with daily use.
The paper ‘The effect of daily usage of Listerine Cool Mint mouthwash on the oropharyngeal microbiome: a substudy of the PReGo trial’ by J.G.E. Laumen, C. Van Dijck, S.S. Manoharan-Basil, T. de Block, S. Abdellati, B.B. Xavier, S. Malhotra-Kumar and C. Kenyon, published in Journal of Medical Microbiology .
