Kim Harley, a reproductive epidemiologist at the University of California-Berkeley

Kim Harley, a reproductive epidemiologist at the University of California-Berkeley

A new study released today suggests that consumers can quickly reduce the amount of hormone-disrupting chemicals in their bodies by switching personal care products.

Researchers at the University of California-Berkeley asked 100 teenage girls in Salinas, Calif. to stop using their normal makeups, soaps and shampoos and instead use products free of common ingredients that have been shown to interfere with the endocrine systems of animals or mimic the actions of hormones on human cells in laboratories.

After switching products for just three days, the girls showed a 27 to 45 percent reduction in levels of several chemicals – called phthalates, parabens, triclosan and oxybenzone – in their urine.

The impact most of these chemicals have on people remains unclear, although human studies have linked phthalates to respiratory symptoms, neurobehavioral problems and obesity in children.

“We don’t know what the long-term health effects of exposing our bodies to these chemicals are, but there’s reason to be concerned,” said the study’s lead author, Kim Harley, a reproductive epidemiologist.

The U.S. Food and Drug Administration has limited authority over the ingredients that go into personal care products. The FDA doesn’t require manufacturers to prove that their products are safe before putting them on the market and is not authorized to recall personal care products.

The Berkeley study analyzed urine samples of the 100 girls, all Latinas, before and after they switched products and screened them for concentrations of nine chemicals. Overall, after the switch, concentrations decreased for all of the chemicals except for two rarer types of parabens, which increased, although the levels were low. Parabens are a class of chemicals used as preservatives and antibacterial agents in personal care products.

“That was really surprising,” said Harley, who noted that researchers specifically chose products that were paraben free. She hypothesized that paraben-free products could just be switching to less-common parabens, although she emphasized she didn’t know the cause for the increase.

The study was born out of a relationship the Center for Environmental Research and Children’s Health at UC Berkeley has with Salinas, a rural, largely Latino community northeast of Monterey. Harley said the center has been working in the community for years and wanted to do a project in which local young people could actually participate in designing and carrying out a study.

When researchers started talking to local teenage girls about potentially harmful chemicals in their cosmetics, Harley said the girls were fascinated and several ultimately helped conduct the study.

“It was a topic that spoke to them,” she said.