Triclosan, an antibacterial that's a common ingredient in soaps, shampoos, toothpastes, and other household items, has been linked to liver cancer. A study at the University of California, San Diego School of Medicine found that long-term exposure to the chemical causes liver fibrosis and cancer in laboratory mice through mechanisms that are similar in humans.
"Triclosan's increasing detection in environmental samples and its increasingly broad use in consumer products may overcome its moderate benefit and present a very real risk of liver toxicity for people, as it does in mice, particularly when combined with other compounds with similar action," said study leader Robert H. Tukey, Ph.D.
The study found that mice exposed to triclosan for six months — the equivalent of 18 human years — had more chemical-induced liver tumors than mice not exposed to the chemical, and the tumors were also larger.
Researchers believe that triclosan interferes with a protein that helps the body neutralize chemicals in the body.
Previous studies found traces of triclosan in 97 percent of human breast milk samples, and also in the urine of 75 percent of people tested.
"We could reduce most human and environmental exposures by eliminating uses of triclosan that are high volume, but of low benefit, such as inclusion in liquid hand soaps," said researcher Bruce D. Hammock, Ph.D. "Yet we could also for now retain uses shown to have health value—as in toothpaste, where the amount used is small."
The study was published by Proceedings of the National Academy of Sciences.
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