Does using Listerine mouthwash increase the risk of cancer?
Fresh Air and a Clean Feeling in the Mouth - that's what mouthwash promises. But according to a study, a specific type might not only harm the mouth flora but also be carcinogenic. How real is the danger? An expert explains.
Mouth rinsing is a daily hygiene routine for many people. However, according to a Belgian study, there is a possible link between a certain mouthwash and the development of colon- or rectal cancer. It is "Listerine Cool Mint," which has been sold in Germany since 1995.
The authors of the study, published in the scientific journal "Journal of Microbiology Society," aimed to find out "if the daily use of Listerine Cool Mint influences the composition of the oral microbiome." To date, it had been unclear whether the antimicrobial mouthwash from Listerine "promotes a healthy mouth microbiome or undermines it."
According to the study, 59 participants used "Listerine daily for three months, followed by three months of placebo mouth rinsing or vice versa." The researchers then found that the composition of the oral microbiome had "significantly differed." This means that after three months of daily Listerine use, the microbiome of the participants had changed in such a way that there were more bacteria present that were reportedly associated with "periodontal diseases, colon- or rectal cancer, and systemic diseases."
Do these results mean that regular use of antibacterial mouthwashes can promote cancer?
Bacteria in the Mouth Don't Have to be Bad
No, says General Practitioner and Medical Journalist Dr. Christoph Specht. Based on the study results, one cannot say that Listerine causes cancer - "that would be completely wrong," he explains in an interview with RTL/ntv.
However, the study results highlight another important aspect, according to the medical expert. Excessive hygiene can destroy necessary microbiomes, which in turn can have negative health consequences in the long term. Contrary to popular belief, bacteria in the mouth are not only something bad.
People also have a microbiome in their mouth - "a specific composition that is good for us," says Specht. Regular use of antibacterial agents, such as mouthwash, could potentially kill not only harmful but also beneficial bacteria. Studies from previous years, according to Specht, have shown that it is not the best idea to use mouthwash every day. "We need bacteria. Without bacteria, we wouldn't have any digestion and no defense," says Specht. They also play a role in the mouth in maintaining a functioning flora. "If we intervene too strongly, we disrupt a functioning system, which is not good."
More Harm Than Good
Specht's appeal is therefore to all those who tend towards excessive hygiene: "Occasional use of mouthwash is certainly a good idea and can also make sense." But: "The idea that we have to live germ-free or that there should be no germs in our body is completely wrong." By doing so, one would harm one's health more than help it.
The company Kenvue, to which Listerine belongs, responded to an inquiry from RTL/ntv as follows: "There is no evidence that Listerine causes cancer." The mouthwash is safe if used as indicated on the label.
Furthermore, the company criticizes that "the study has several methodological weaknesses, which could question the validity of the results." According to Kenvue, "important controls in the study design are missing, as well as sufficient robustness [...], to make conclusions about potential effects on human health."
This article first appeared on RTL.de.
The study suggests that long-term use of Listerine Cool Mint, a specific antimicrobial mouthwash, could alter the oral microbiome, leading to an increase in bacteria linked to periodontal diseases, colon- or rectal cancer, and systemic diseases. Though Dr. Christoph Specht, a General Practitioner and Medical Journalist, emphasizes that the study does not prove that Listerine causes cancer, he stresses the importance of preserving the oral microbiome for overall health, advising against excessive use of antibacterial agents like mouthwash.
