Chemical in soap, toothpaste impairs muscle strength

Triclosan, an antibacterial widely used in soaps, deodorants, toothpastes and other body-care products, reduces muscular strength, according to a mice study.

"Triclosan is found in virtually everyone's home and is pervasive in the environment," said Isaac Pessah, professor and head of molecular biosciences in the University of California-Davis School of Veterinary Medicine and principal study investigator.

"These findings provide strong evidence that the chemical is of concern to both human and environmental health," Pessah was quoted as saying by the journal Proceedings of the National Academy of Sciences.

Triclosan is commonly found in antibacterial body-care products such as hand soaps as well as deodorants, mouthwashes, toothpaste, bedding, clothes, carpets, toys and trash bags, according to a California statement.

The Environmental Protection Agency in 1998 estimated that more than one million pounds of triclosan are produced annually in the US. Traces are present in waterways and aquatic organisms, from algae to fish to dolphins, as well as in human urine, blood and breast milk.

Investigators performed several experiments to evaluate the effects of triclosan on muscle activity, using doses similar to those that people and animals may be exposed to during everyday life.

In "test tube" experiments, triclosan impaired the ability of isolated heart muscle cells and skeletal muscle fibres and muscle movements, including heartbeats to contract.

Besides, the mice had an 18 percent reduction in grip strength for up to 60 minutes after being given a single dose of triclosan. Grip strength is a widely used to measure of limb strength.

The team also found that triclosan impairs heart and skeletal muscle contractility in living animals.

Anaesthetised mice had up to a 25 percent reduction in heart function measures within 20 minutes of exposure to the chemical.

"The effects of triclosan on cardiac function were really dramatic," said Nipavan Chiamvimonvat, professor of cardiovascular medicine at California-Davis and study co-author.

"Although triclosan is not regulated as a drug, this compound acts like a potent cardiac depressant in our models," concluded Chiamvimonvat.