Is your antibacterial soap safe? UMaine researchers study common ingredient

Examine the label on one of the many antibacterial products in your home, and you’ll likely find “triclosan” listed as an ingredient.

The antimicrobial chemical was once used only in hospitals, but in the 1990s manufacturers began adding it to soaps, body washes, toothpaste, deodorants, facial cleansers, and countless other personal hygiene products. You’ll even find it in fabric, plastics and clothing, from yoga mats to socks, to inhibit bacteria and mildew growth.

As its use proliferated, concerns mounted that the synthetic chemical might do more harm than good. Some lab studies have found triclosan can disrupt hormones and promote drug-resistant bacteria, or “superbugs.”

In December, the U.S. Food and Drug Administration announced it would require soap manufacturers to demonstrate that triclosan and similar chemicals are safe and effective. Some companies have since pulled them from their products.

The chemicals are not only potentially harmful, but may not offer any benefits in household soaps. There is no evidence that over-the-counter antibacterial soap products are any more effective at preventing illness than washing with plain soap and water, according to Colleen Rogers, a lead microbiologist at FDA.

A team of researchers at UMaine hopes to shed more light on triclosan’s effects on the body.

“If you go Hannaford and you go down the aisle of personal care products, you’ll see a lot of antibacterial products containing triclosan,” said lead researcher Julie Gosse, a UMaine assistant professor of molecular and biomedical sciences. “It’s amazing how many different things.”

The National Institutes of Health recently awarded Gosse more than $420,000 for a three-year research project into triclosan. A dearth of studies into how the  chemical affects humans and other mammals has left many questions unanswered, she said.

Gosse and her team are examining how the chemical inhibits the body’s “mast cells,” which sometimes fight cancer.

“They’re involved in pretty much every disease that you can think of and they’re found in almost every body tissue,” Gosse said. “We think if triclosan is affecting these cells it could have potentially negative effects. Or even potentially useful pharmacological effects in certain situations.”

Inhibiting mast cells may ease some allergic conditions such as eczema. But the cells also respond to cancer, fight bacterial infections, and play a role in central nervous system disorders such as autism.

Triclosan has its place, such as in hand scrubs surgeons use to eliminate bacteria, Gosse said. But the chemical became ubiquitous without proof that it’s safe for everyday use, she said.

A decade ago, a national study detected triclosan in the urine of 75 percent of participants. The levels weren’t proven harmful, but public health experts say more research is needed.

Triclosan is absorbed readily into the skin. Most products contain concentrations much higher than the level found in Gosse’s lab to affect cell function in mammals, she said.

For her part, she avoids products containing triclosan.

“I don’t think it’s a good idea for the U.S. population to be mass exposed to this stuff,” Gosse said.

In May, Minnesota issued a statewide ban on all products containing triclosan.

Because of its pervasive use, Gosse says triclosan has now also made its way into the water supply.

She hopes the FDA will one day consider her research in its review of antibacterial products. The NIH grant will allow her team to continue exploring the mechanisms underlying the effects of triclosan. They’ll use a high-resolution microscope invented by UMaine physicist Sam Hess to study how mammalian cells interact with the chemical on a molecular level.

Also part of her research team are Lisa Weatherly and Juyoung Shim, graduate students in Gosse’s lab, and students from Hess’ lab.

“A lot of times what we hope, as scientists in an academic setting doing basic research, is that our findings will be taken and used by regulators,” Gosse said.

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Jackie Farwell

About Jackie Farwell

I'm the health editor for the Bangor Daily News, a Bangor native, a UMaine grad, and a weekend crossword warrior. I never get sick of writing about Maine people, geeking out over health care data, and finding new ways to help you stay well. I live in Gorham with my husband Nick and our hound dog Riley.