Using some antibacterial soaps may promote tumor growth, according to a study just published in Proceedings of the National Academy of Sciences. The findings add to a body of concerns about triclosan, one of the most common antimicrobial chemicals in consumer products from detergents to cosmetics, including links to allergy development in children, and potentially to breast cancer via disruption of hormone signals that may also cause thyroid dysfunction and weight gain.
"Our interest in this was that triclosan is just so abundant," said lead researcher Robert Tukey, a professor at University of California San Diego School of Medicine. "It's really everywhere in the environment."
Today's study found that mice who were exposed to triclosan regularly for six months showed abnormal cell proliferation, liver fibrosis, and inflammatory responses—all of which, the researchers write, "resemble the environment within which human liver cancer forms." The researchers expect that the same triclosan-induced formation of liver tumors "would occur in humans as it occurs in mice."
Triclosan is regulated in many countries, but the U.S. isn't among them. In 1974 the Food and Drug Administration (FDA) proposed a ruling on the safety of triclosan; but, four years later, the agency said that was not possible due to insufficient evidence. In 2010, still with no FDA ruling, the National Resources Defense Council sued the FDA over the matter. Still today there's no ruling, but the FDA has said that it will commit to something by 2016. The chemical is in an estimated 75 percent of antimicrobial soaps and body washes, though some companies have begun voluntarily phasing it out due to health concerns. Products like Johnson's baby shampoo and Palmolive no longer contain triclosan.