- Author: Kathy Keatley Garvey
The controversial antibacterial chemical is grabbing nationwide attention with the recent cover story of “Triclosan Under the Microsope” in Chemical Engineering News. The article quotes Bruce Hammock, a UC Davis distinguished professor who holds a joint appointment in the Department of Entomology and Nematology and the UC Davis Comprehensive Cancer Center.
“I'm getting love notes and hate mail,” he said, adding "“My colleagues and I are continuing to look at the positive and negative aspects of triclosan. It clearly has some negative effects on mammalian biology, but it is a very potent microbial and quite inexpensive, and relatively safe.”
Triclosan, first used in healthcare settings in the 1960s, is now found in products throughout the home—in everything from hand sanitizers, toothpastes, mouthwashes, deodorants and cosmetics to beddings, clothes, toys, carpets and trash bags.
Last month Minnesota became the first state to ban the ingredient in soaps and cleaning products. Other states concerned about the chemical's effects on human and environmental health may follow.
Hammock said that he and UC Davis colleagues molecular biologist David Mills and chemist Bruce German are now looking at the effects on gut bacteria.
“And, with Bob Tukey at UC San Diego, we are looking at enzyme induction in mammals and possible health risks,” Hammock said. Tukey, professor of pharmacology and chemistry and biochemistry, directs the UCSD Superfund Basic Research Program, while Hammock directs the UC Davis Superfund Program.
The U.S. Environmental Protection Agency in 1998 estimated that the U.S. produces more than 1 million pounds of triclosan annually, and that scientists can detect the chemical in waterways, aquatic organisms, and in human urine, blood and breast milk.
Concern over the controversial compound is swirling with the June 23rd publication of “Triclosan Under the Microscope.”
Hammock told author Jyllian Kemsley that when medical providers first started using triclosan as a surgical scrub, “it replaced some really scary compounds.”
He said that “Triclosan is much less toxic, more effective, and more biodegradable” than hexachlorophene and other common biocides of the time.
Wrote Kemsley: “But then triclosan made its way out of the operating room and into mass consumer products. In that context, its toxicity profile and environmental lifetime make the cost-benefit analysis murkier.”
“To me that doesn't say rush out and ban it,” Hammock told her, advocating careful consideration for mass use. He said washing hands with plain soap and water will likely fit most needs. Triclosan is a very effective anti-microbial but probably it is overused in many cases.
Kemsley wrote that some people may be more susceptible to harm, “such as those with genetic variations that reduce their ability to metabolize triclosan, leaving them with higher blood concentrations.” Some scientists worry if the toxicity level is worth it to reduce disease and also whether it promotes drug resistance.
Kemsley drew attention to the 2012 UC Davis study that shows that triclosan hinders cardiac and skeletal muscle contraction in mice and fish. The study, published in the Proceedings of the National Academy of Sciences (PNAS) and authored by a 13-member research team headed by Isaac Pessah and Nipavan Chiamvimonvat of the School of Veterinary Medicine and Hammock, found that triclosan hinders muscle contractions at a cellular level, slows swimming in fish and reduces muscular strength in mice.
“The effects of triclosan on cardiac function were really dramatic,” Chiamvimonvat, professor of cardiovascular medicine, related following the PNAS publication. “Although triclosan is not regulated as a drug, this compound acts like a potent cardiac depressant when administered at high doses in our models.”