Some plastic teething toys used by infants might contain chemicals that could interfere with the production of hormones needed for normal growth and development, a small German study suggests.
Researchers did lab tests on 10 plastic teethers and found two contained chemicals known as endocrine disruptors because they can interfere with the body's endocrine system, a network of glands that make hormones responsible for functions including growth, metabolism, reproduction and tissue function.
"We detected hormonal activity leaching from two out of 10 plastic teethers," senior study author Martin Wagner, a toxicology researcher at Goethe University in Frankfurt, said by email. "Our study documents that certain baby toys contain and leach chemicals we certainly do not want to have in there."
Wagner and colleagues didn't identify what manufacturers made the teething toys or where they purchased them in their study published in the Journal of Applied Toxicology.
In lab tests, two of the teething toys had chemicals believed to interfere with the production of the reproductive hormones oestrogen and androgen, the study found. One contained chemicals known as parabens.
Parabens are among the most commonly used preservatives in cosmetic products. Chemically, parabens are compounds of what's known as p-hydroxybenzoic acid. The most common parabens used in cosmetics are methylparaben, propylparaben, and butylparaben. Typically, parabens are used in combination to increase their effectiveness.
Some parabens are banned from cosmetics in the European Union, but the U.S. Food and Drug Administration has not limited use of the products.
Greatest risk in the womb
Parabens and other endocrine disruptors may have developmental, reproductive, neurological and immune system side effects, and they may be found in pharmaceuticals, cosmetics, pesticides, plastics, detergents, food, toys, and flame retardants, according to the U.S. National Institutes of Health.
Previous research has found endocrine disruptors may pose the greatest risk to babies developing in the womb in during the first months of life when organ and neural systems are forming, according to the NIH. More studies are needed, though, to understand whether these products increase the risk of cancer or lead to infertility.
Scientists don't know exactly what amount of parabens might be harmful, and it's impossible for parents to know whether these chemicals might be in plastic toys, Martin said.
"My parents made me chew on a carrot from the fridge when I was teething," he recalled.
Without knowing where the teething toys tested in the study were made or sold, it's hard to know how widespread the problem might be or whether products available outside of Germany might have higher or lower amounts of parabens, said Dr. Luz Claudio, chief of international health at Mount Sinai School of Medicine in New York.
Still, parents may want to exercise caution with plastic teething toys, Claudio, who wasn't involved in the study, said by email.
"There is not any way that parents can be sure whether the teethers that they buy have parabens or not," Claudio said. "For my daughter, I used shaved ice or frozen fruits to alleviate teething pain."
SOURCE: http://bit.ly/1J9niue Journal of Applied Toxicology, online May 18, 2015.
Image: Child with teething toy from Shutterstock