Chemical in many antibacterial soaps linked with impaired muscle function

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Published August 14, 2012

| FoxNews.com

Introduced in the 1970s, the compound triclosan has become an increasingly popular ingredient in many antibacterial soaps and other personal-care items, such as deodorants and mouthwashes.  However, as the chemical’s popularity continues to grow, a recent report has raised concerns about some frightening risks that triclosan could pose to public health.

A new study published in the Proceedings of the National Academy of Sciences has revealed that exposure to triclosan is linked with muscle function impairments in humans and mice, as well as slowing the swimming of fish.  By reducing contractions in both cardiac and skeletal muscles, the chemical has the potential to contribute to heart disease and heart failure.

The researchers from the University of California, Davis, and the University of Colorado decided to examine the possible effects of triclosan due to recent literature raising health concerns about the chemical, as well as substantial increases in its production.

“We consider [triclosan] a high volume chemical,” Dr. Isaac Pessah, professor and chair of the Department of Molecular Biosciences in the UC Davis School of Veterinary Medicine, as well as the study’s lead author, told FoxNews.com.  “Its production levels are quite high, and the levels in humans have been increasing since it was first used as an antibacterial agent in the early ‘70s.  So the body levels in humans – including plasma, urine and breast milk – have been steadily increasing.”

“The levels in the environment have been increasing as well, because it can’t all be trapped in the treatment plants,” Pessah added about triclosan’s prevalence.  “[Companies] try to prevent some chemicals getting out past the water treatment plants so they can dispose of them in a different way, but they can’t capture all of [triclosan] because there is so much of it.”

Primarily used in antibacterial hand soaps, triclosan can also be found in a number of bath and household products, including mouthwashes, toothpastes, deodorants, bedding, washcloths and towels, kitchen utensils and toys.

Effects on muscle contraction

Having studied previous research implicating triclosan in allergy development and the growth of some cancers, Pessah and his team decided to test the compound’s effects on muscle function after comparing it to long established hazardous chemicals.

“We’ve been working on polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), the major flame retardants now being considered environmental risk factors,” Pessah said.  “We’ve know about PCBs for a while.  These tipped us off based on their similar structure to triclosan.  So we looked at it in more detail, and we were quite surprised that it had so much potent activity.  Given all the scientific literature, there’s virtually nothing about its ability to interfere with contraction of the heart.”

In their experiment, the researchers produced fully functioning cells derived from primary muscle cells in humans.  Because the cells were derived and not engineered, Pessah said the experiment more accurately determined triclosan’s effects in humans.

After exposing the cells to levels of triclosan similar to amounts people use daily, Pessah and his colleagues found that the chemical greatly interfered with the muscles’ ability to contract when stimulated, a response known as ‘excitation-contraction coupling.’

“Excitation-contraction coupling is essential for muscle contraction,” Pessah said.  “If you interfere with that process, it can be lethal and certainly debilitating.  We were very surprised that triclosan essentially impaired ECC in both cardiac muscle cells and skeletal muscle cells…It did so at relatively low concentrations and relatively quickly.”

To add on to these shocking results, the team also found that exposure to triclosan in mice resulted in an 18 percent reduction in gripping strength as well as a 25 percent reduction in heart function – all within an hour of the chemical’s introduction.  Going one step further, the scientists studied the effects of triclosan exposure on fathead minnows, ultimately finding a significant reduction in swimming activity.

Implications for public health

While the results of the study are staggering, Pessah noted that usage of triclosan will not lead to immediate heart failure.  Most people are able to metabolize triclosan quickly so that it is readily excreted through urine.  But a portion of the population does not metabolize the compound as quickly, and the chemical can remain active in the blood for a longer period of time.

However, the main concern the scientists have is the potential for triclosan exposure to contribute to already debilitating heart conditions.

“The target we’ve identified has been implicated in the impairment of heart function over a period of time,” Pessah said.  “If an average individual loses 10 percent of their cardiac function, they’re not going to feel it.  But if you’re a person with heart disease already at 50 percent of heart function capacity, reducing 10 percent or 20 percent could markedly hurt your health.”

Pessah said their findings present yet another health concern posed by triclosan, adding to previous accusations of its toxic and carcinogenic nature.  Because of triclosan’s prevalence in both the environment and the household, the agent has been flagged for further risk-benefit analysis by the FDA, but no final recommendation has been made yet.  Currently, manufacturers utilizing triclosan are required to list it as an ingredient on their product labels.  

Pessah hopes this new study will add to the FDA’s considerations, as well as help consumers become more aware of the compound’s effects.  According to Pessah, triclosan is not an essential ingredient for these products.

“When people ask me about this, I say that we’ve been taking great care to buy products without triclosan,” Pessah said.  “Instead, buy disinfectant hand wash based in alcohol.  There’s no literature that says it’s more useful than just soap and water. The risks definitely outweigh the benefits.”

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