By Anna Tarasova‘19

Triclosan (TCS) is an antimicrobial chemical frequently used in household products, including toothpastes, soaps, and toys. Because it is so common, the overwhelming majority of the population comes into contact with it almost every day. The National Health and Nutrition Examination Survey found TCS in approximately 75% of urine samples of individuals tested in the United States. TCS is also among the top 10 U.S. river pollutants. Past studies have suggested the potentially harmful effects of high doses of TCS, and it was removed from handwashing soaps by order of the U.S. Food and Drug Administration (FDA) in 2016.

Dr. Haixia Yang and her colleagues at the University of Massachusetts examined the effects and mechanisms of TCS exposure on samples of normal mice, mice with induced inflammatory bowel disease (IBD), and mice with induced colon cancer. The mice were introduced to TCS through their diet for 3 weeks. The concentrations of TCS used were 10 ppm and 80 ppm, similar to those found in the plasma of a sample of human volunteers. The researchers found that TCS exposure was correlated with low-grade colonic inflammation (colitis) in normal mice and exacerbated bowel inflammation in IBD mice. Mice with colon cancer were determined to have, on average, more tumors as well as increased tumor size. Overall, these findings suggest that TCS may have an adverse effect on gut health. More research is needed to accurately gauge the exposure and absorption of TCS in a human population. The researchers acknowledge that the time span of the study was only a few weeks, whereas humans may be exposed to TCS throughout their lifespan. TCS is only one of many potentially harmful additives that humans encounter daily through household products. Dr. Yang calls for further studies examining the effects of these additives on humans and on the environment.

References

1. H. Yang, et. al., A common antimicrobial additive increases colonic inflammation and colitis-associated colon tumorigenesis in mice. Science Translational Medicine, (2018). doi: 10.1126/scitranslmed.aan4116;
2. Image retrieved from: https://upload.wikimedia.org/wikipedia/commons/4/49/Toothpasteonbrush.jpg