According to the results of a controversial study by researchers at the University of California at Davis, and Colorado, both in the United States, triclosan, a chemical widely used in antibacterial hand soaps and other personal care products, hinders muscle contraction at the cellular level, swimming in fish slows and reduces muscle strength in mice.
The report of the findings has been published in the journal PNAS (Proceedings of the National Academy of Sciences). Triclosan is commonly found in personal care products such as antibacterial soaps, deodorants, liquid mouthwashes, toothpastes, carpets, garbage bags, and even clothing and toys.
The Environmental Protection Agency of the United States estimated in 1998 that about 450 tons of triclosan are produced annually in the United States, being detectable substance into waterways, aquatic organisms ranging from algae to fish and dolphins, as well as the urine, blood and human breast milk.
The team of Professor Isaac Pessah, professor in the Department of Molecular Biosciences in the School of Veterinary Medicine, University of California at Davis, conducted several experiments to evaluate the effects of triclosan on muscle activity, using doses similar to those that people and animals may be exposed during their daily lives.
In experiments “in vitro”, triclosan contraction deteriorated capacity of isolated cells of cardiac muscle and skeletal muscle fibers. Specifically, researchers evaluated the effect of triclosan on molecular channels muscle cells that control the flow of calcium ions, producing muscle contractions. Normally, electrical stimulation (“excitation”) of isolated muscle fibers under experimental conditions causes a muscle contraction, the fundamental basis of any muscle movement, including heartbeat. But in the presence of triclosan, normal communication between two proteins that act as calcium channels was flawed, causing a malfunction in the fibers of skeletal muscle and cardiac muscle cells.
The team also found that triclosan harms skeletal muscle contractility and heart in living animals. In anesthetized mice, there was a 25 percent reduction in measures of cardiac function in the first 20 minutes after exposure to triclosan.
In addition, the mice had an 18 percent reduction in grip strength for 60 minutes after receiving a single dose of triclosan.
Finally, researchers examined the effects of exposure to triclosan in fish species Pimephales promelas, commonly used as a model organism to study the potential effects of aquatic pollutants. Those who were exposed to triclosan in water for seven days, had considerably reduced their swimming activity, both compared to the control group subjects during normal swimming, as in swimming designed to mimic the avoidance behavior of fish to the threat of a predator.
Nipavan Chiamvimonvat, professor of cardiovascular medicine at the University of California at Davis, and co-author of the study, cautioned, however, that translate the results of these animal models to humans will require further investigation. But he stresses that the fact that the effects are less clear in various animal models and in different experimental conditions, provides fairly solid evidence that triclosan could have effects on human and animal health at current levels of exposure.
Although triclosan was first developed to prevent bacterial infections in hospitals use does seem appropriate, applications have spread to many fields, probably too many.
Moreover, according to the U.S. Administration Food and Drug Administration (FDA), apart from its usefulness in some toothpaste to prevent gingivitis, there is enough solid evidence that triclosan provides other clear benefits to health in the home, or that use of antibacterial soaps everyday way more effective than regular soaps modern. Some experts are also concerned about the possibility that the overuse of antibacterial products do develop resistance in some strains of bacteria, with the result that they become stronger and dangerous.
Because the chemical structure of triclosan resembles several very persistent toxic chemicals in the environment, the FDA and the U.S. Environmental Protection Agency (EPA) are conducting further evaluations of the risks of widespread use of triclosan. Depending on the results of these evaluations, the scope of use of this material may be restricted.
Bruce Hammock, study co-author and professor in the Department of Entomology, University of California at Davis, value: “The triclosan may be useful in some cases; however, it has become a common element of added value in the market, which may be doing more harm than good. Least, our results invite to significantly reduce their use.”