Antibacterials and Liver Disease

By Jane Farrell

A product meant to fight bacteria could lead to liver cancer, according to researchers. The newest study of triclosan comes months after an earlier study determined that the substance showed up in the urine of people who used it.

It’s also been linked to the impairment of muscle contraction and hormone disruption.

Triclosan, an antimicrobial commonly found in soaps, shampoos, toothpastes and many other household items, carries potentially serious consequences as a result of long-term exposure, according to a study conducted by investigators from the University of California, San Diego School of Medicine.

Their research showed that triclosan causes liver fibrosis and cancer in lab mice via mechanisms that are similar to those in humans.

“Triclosan’s increasing detection in environmental samples and its increasingly broad use in consumer products may overcome its moderate benefit and present a very real risk of liver toxicity for people, as it does in mice, particularly when combined with other compounds with similar action,” said Robert H. Tukey, PhD, professor in the departments of Chemistry and Biochemistry and Pharmacology.

The investigators discovered that triclosan disrupted “liver integrity” and damaged liver function in mouse models. Mice who were exposed to triclosan for six months (roughly equivalent to 18 human years) were more susceptible to chemical-induced liver tumors. Additionally, they had larger and more frequently occurring tumors than did those who weren’t exposed to triclosan.

Evidence from the study indicates that triclosan may do its damage by interfering with a protein responsible for clearing away foreign chemicals in the body. Because of this intereference, liver cells multiply and eventually turn fibrotic. And that can lead to tumor formation.

Studies have found traces of triclosan in 97 percent of breast milk samples from lactating women and in the urine of nearly 75 percent of people tested. It is also one of the most frequently detected compounds in streams in the United States.

The substance is now under scrutiny by the federal Food and Drug Administration (FDA).

The findings were published in the Proceedings of the National Academy of Sciences.