Several antibacterial compounds can no longer be added to consumer soaps sold in the United States, the Food and Drug Administration ruled last week. Two of the most commonly used compounds — triclosan and triclocarban — have been found to harm animals.
Stanford’s Stephen Luby, MD, a professor of medicine, led a 2005 study that helped inform the FDA’s decision, and he recently discussed the issues in a Q&A with the Woods Institute for the Environment. An excerpt:
How did your 2005 study in Pakistan shed light on the question of antibacterial soap’s efficacy?
That study compared the health outcomes from antibacterial soap and soap that was indistinguishable from and otherwise chemically identical to the antibacterial soap, but without triclocarban. Compared with a control group who received school supplies, children living in households who received soap and handwashing promotion had 52 percent less diarrhea, 50 percent less pneumonia and 45 percent less impetigo. Impetigo, a skin infection, was a particularly important outcome, because laboratory studies had suggested that triclocarban would have antibacterial activity against the organisms that most commonly caused impetigo. There was, however, no difference in any of the health outcomes between children living in households who received the plain soap compared with children who received the antibacterial soap.
The study was influential, because its blinded design and large size provided a rigorous test of the hypothesis of the health benefit of antibacterial soap. The finding that there was a major benefit to handwashing was an important outcome and demonstrated that people were using the soap fine. Thus, the absence of any additional benefit with the antibacterial compound was a scientifically persuasive negative finding.
This decision required industry groups to provide compelling evidence the compounds provided a benefit, which they apparently were unable to do, Luby said. But that doesn’t mean the products are extremely dangerous, he said:
I think it would be fine for people to use the rest of the antibacterial soap that is sitting around the house. That said, we can all be grateful that going forward neither they nor the environment needs to be exposed to these antibacterial compounds.
Interestingly, the ban does not extend to all consumer products, such as toothpaste.
Previously: FDA changes regulatino for antibiotic use in animals, Using video surveillance to gain insights into hand washing behavior and Researchers challenge conventional wisdom to identify source of lead contamination in Bangladesh
Photo by Lisa Salamida