"Soap Causes Cancer!"

“Soap causes cancer!” screamed numerous news outlets this week. The findings from a study produced by researchers from the University of California have been grossly exaggerated.

The university’s press release, “The Dirty Side of Soap,” misrepresents the study’s results. It claims that triclosan, a common antimicrobial agent in hygiene products, “causes liver fibrosis and cancer in mice.” By exaggerating the scope of the research, the press release misleads readers, including journalists.

Shortly after the press release was published, fear-mongering articles from popular news sources arose. They unduly warned readers that triclosan could harm their health. One source called the research a “cancer scare.” Others falsely reported the findings as conclusive and exaggerated the study’s relevance to humans. Many writers distorted the scope of the research to the extent that the “facts” in their articles barely resemble the study’s conclusions.

Contrary to the university’s press release and several online articles, the researchers did not conclude that triclosan causes cancer in mice. The researchers found that large amounts of ingested triclosan may promote tumour growth in mice. To observe triclosan’s effect on tumour growth, the researchers injected mice with a chemical (diethylnitrosamine) that is capable of inducing liver cancer.

In a separate group of mice, the researchers found that ingested triclosan can lead to liver damage.

The study results cannot be applied to humans. Although mice are used to model human disease, some chemicals that are toxic to mice may not be toxic to humans. As the authors of the study recommend, long-term observational studies in humans must be conducted before triclosan’s effect on humans can be understood. Also, since people do not eat large amounts of triclosan as the mice did in the study, the results observed in the mice are not reasonable to expect in humans.

Although the study does not provide enough evidence to condemn antibacterial soap, consumers may want to reconsider purchasing antibacterial soaps for other reasons. Though triclosan and other antibacterial agents are useful to healthcare workers, Health Canada notes that antibacterial soap is usually unnecessary in the home. Further, when triclosan is washed down the drain, it may cause environmental damage. Triclosan in toothpaste, however, can significantly prevent plaque and gingivitis, according to the Cochrane Review.

The study was published in Proceedings of the National Academy of Sciences, a scientific journal. According to standard practice, to access an article in the journal, one must either belong to an organization or institution that purchases a subscription, or pay for access to the article. Consequently, most people do not have access to articles published in journals.

Even if the public were granted access to journals, articles would still be inaccessible. Few people possess enough scientific literacy to interpret and evaluate a biological study. Most people rely on writers and journalists to identify and publicize important research findings.

It is the responsibility of science correspondents to be scientifically literate and commit to reporting findings accurately. They must critically evaluate a study and understand the significance of findings before they can communicate truthfully. Just as ignorance of the law is not an excuse for committing a crime, lack of scientific literacy is not an excuse for distributing false information.

Shocking and overblown headlines commit a disservice to readers. Exaggerated research findings may serve to boost traffic to websites, increase research funding, or sway consumers to purchase certain products. None of these reasons justify invoking gratuitous fear in readers.

The latest research does not demonstrate whether triclosan negatively affects human health. It is unethical to claim otherwise. The media must uphold the integrity of science to produce ethical journalism. Fear mongering and sensationalizing disrupts the shared foundation of science and journalism: to report truthfully.