A new study on mice populations suggests that long-term exposure to an antimicrobial – triclosan- commonly found in many personal hygiene products could cause cancer and liver fibrosis.
The study was conducted by Prof. Robert H. Tukey of the University of California-San Diego and Prof. Bruce D. Hammock of the University of California-Davis and was recently published in the Proceedings of the National Academy of Sciences.
Triclosan is frequently added to liquid hand soap, shampoo and other personal hygiene products in order to slow down or prevent bacteria, fungi or mildew proliferation.
Triclosan can be also found in toothpaste and antiperspirants and it is commonly used as an agent to preserve sport shoes, clothing articles, sealants and several household products.
Some other studies suggest that the agent might promote bacterial resistance or alter hormone regulation in mice.
The Food and Drug Administration (FDA) previously stated that there was not enough evidence to suggest triclosan was dangerous to humans. But after Prof. Tukey, Prof. Hammock and their team’s recent findings, FDA should at least take it into consideration.
The researchers found out that triclosan proved toxic to laboratory mice by disrupting a protein responsible for clearing foreign chemicals from their body. This protein is called constitutive androstane receptor (CAR) and it is also present in humans.
Disruption to CAR causes the liver cells to uncontrollably proliferate and thus causing fibrosis – production of excess tissue. On the long run, repeated triclosan exposure can lead to liver cancer.
“Although animal studies require higher chemical concentrations than predicted for human exposure, this study demonstrates that triclosan acts as a hepatocellular carcinoma (HCC) tumor promoter and that the mechanism of triclosan-induced mouse liver pathology may be relevant to humans.”, the research team said.
The team was also concerned about the very high human exposure to triclosan. According to a past research report there were identified traces of the agent in 97% of breast milk samples of breastfeeding mothers and 75% of urine samples.
However, Prof. Hammock suggested that, in order to be toxic to humans, individuals may need to be exposed to high volumes of triclosan over long periods of time. In his opinion human exposure to the antimicrobial could be drastically reduced by “eliminating uses of triclosan that are high volume, but of low benefit, such as inclusion in liquid hand soaps.”
On the other hand, triclosan has been shown to bring some health benefits on a low exposure level. For example, toothpastes containing small amounts of the agent are an effective factor in preventing gingivitis.