For many health enthusiasts, mouthwash could be a regular part of everyday oral hygiene. However, some of the latest research indicates that this, at times seemingly innocuous, practice does more harm than good particularly when it comes to preserving alcohol-based mouth washes such as Listerine Cool Mint.
The findings of this study by researchers from the Institute of Tropical Medicine in Antwerp, Belgium, raise some serious concerns about exposure. Researchers took a look at the oral microbiome changes after using Listerine daily for three consecutive months. It was found that users had increased amounts of two species of bacteria: Fusobacterium nucleatum and Streptococcus anginosus. Links to severe health risks exist with these two bacteria, such as esophageal and colorectal cancers.
The lead author of the research, Professor Chris Kenyon, said, “Both organisms can cause severe invasive infections and have been linked to various types of cancer, such as esophageal and colorectal cancer.” He warned, “Most people should not be using it and if they do use it, they should use the preparations without alcohol and limit the use to a couple of days.”
The study had 59 volunteers switch between Listerine Cool Mint and a placebo mouthwash for three months at a time. And on top of that, the rise of the bad bacteria was coupled with a corresponding decrease in good bacteria in particular, Actinobacteria. These are microbes that help keep blood pressure in check and also have anti-cancer properties, so their loss is quite worrying in particular.
Dr. Jolein Laumen, corresponding author of the study, commented, “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.”
This study, however, had some major limitations: dietary habits and smoking data of the participants were not recorded, in which case it cannot establish mouthwash use as a predisposing factor. The second point to consider is its generalizability in view of the fact that only men who have s*x with men were involved in the study.
Even the study authors have called for caution despite the various limitations of the research. “These findings suggest that the regular use of Listerine mouthwash should be carefully considered,” wrote the authors in their paper published in the Journal of Medical Microbiology.
“Based on our initial review, the published trial lacks several important design controls and adequate rigour to make any conclusions about potential impact to human health,” said Kenvue, the owner of Listerine. On their part, the company added that “Studies on the impact of LISTERINE® on oral health have been published in hundreds of peer-reviewed publications for more than a century, making it one of the most extensively tested oral mouthwash brands in the world. We continuously evaluate the latest science. There is no evidence that LISTERINE® causes cancer.”
Although this study raises some important questions, one should remember that this is not a new concern to have alcohol in mouthwash. As stated by Alliance Dental, “The alcohol destroys almost all the bacteria in the mouth both the good and the bad. Alcohol-free mouthwash does not destroy all the bacteria but creates a new balance of bacteria in the mouth.” This thing probably can explain the risks observed, but more research is required to draw some definite conclusions.
In view of these findings, health experts advise consumers to switch to non-alcoholic variants of mouthwash products and, of course, consult one’s doctor for more specific advice. As always, a healthy diet, good dental hygiene by way of regular checkups and avoiding known risk factors such as smoking and excessive drinking can go a long way toward keeping you safe.
In summary, while this study failed to establish that alcohol-based mouthwash is the only cause of cancer, it does raise how it should be used with caution and foresight. Being more informed in everyday products like mouthwash could potentially help minimize the risk as new discoveries about the oral microbiome and its relationship with systemic health come about.