Much Ado about Triclosan
This bacterial agent is everywhere—even in toys and kitchenware
The antibacterial chemical triclosan—which is widely used in personal products such as soaps, toothpastes, mouthwashes, and deodorants—is classified as a pesticide by the US Food & Drug Administration (FDA), which defines it as “an ingredient added to many consumer products to reduce or prevent bacterial contamination.”1
Although it was introduced to the marketplace in 1972 to prevent bacterial infections in hospitals, it seems that public germaphobia has spurred its use not only as a recommended regimen for the decolonization of patients whose skin is carrying methicillin-resistant Staphylococcus aureus (MRSA),2 but for everyday bath and oral healthcare products, and in other types of consumer products such as kitchen utensils, toys, bedding, socks, and trash bags.3 This raises concerns that such overuse could cause resistant strains of bacteria to develop in much the same way that antibiotic-resistant bacterial strains are emerging.4
Risks vs. Benefits
However, qualms beyond bacterial resistance have prompted a coalition of health and environmental groups led by Beyond Pesticides and Food & Water Watch to seek triclosan’s removal from the market. Beyond Pesticides, a Washington-based public health and environmental protection organization seeking to eliminate toxic pesticides, states that triclosan’s impact on the consumer market has been aided “by the false public perception that antibacterial products are best to protect and safeguard against potential harmful bacteria.”5 It cites an article in the journal Clinical Infectious Diseases, which concluded that antibacterial soaps show no health benefits over plain soaps.6 The site further presents more ominous concerns, “Studies have increasingly linked triclosan (and its chemical cousin triclocarban), to a range of adverse health and environmental effects, from skin irritation, allergy susceptibility, bacterial, endocrine disruption and compounded antibiotic resistant, tainted water, and dioxin contamination to destruction of fragile aquatic ecosystems.”5
In Triclosan: What Consumers Should Know, the FDA addresses consumer health and safety concerns. In response to the question of whether triclosan provides a benefit in consumer product, its reviews are mixed. “For some consumer products, there is clear evidence that triclosan provides a benefit.” In 1997, the FDA reviewed extensive effectiveness data on triclosan in toothpaste, showing that triclosan in this product was effective in preventing gingivitis. However, the agency found no such support for its use in antibacterial soaps and body washes, saying it provided no benefit over washing with regular soap and water. The FDA further noted animal studies showing that triclosan alters hormones, but concluded that “triclosone is not currently known to be hazardous to humans.”1
Impact on Immune System
According to a University of Michigan School of Public Health study, which was found online in Science Daily, children who are overexposed to antibacterial soaps containing triclosan may suffer more allergies. The researchers, who used data from the 2003-2006 National Health and Nutrition Examination Survey, compared urinary triclosan—as well as BPA— with cytomegalovirus (CMV) antibody levels and diagnosis of allergies or hay fever in a sample of U.S. adults and children over age 6. They found that those under age 18 with higher levels of triclosan were more likely to report diagnosis of
allergies and hay fever.7
“The triclosan findings in the younger age groups may support the ‘hygiene hypothesis,’ which maintains living in very clean and hygienic environments may impact our exposure to micro-organisms that are beneficial for development of the immune system,” said Allison Aiello, associate professor at the U-M School of Public Health and principal investigator on the study. The study suggested that, as an antimicrobial agent found in many household products, triclosan may play a role in changing the micro-organisms to which humans are exposed in such a way that their immune system development in childhood is affected.7
Impact on Muscle Activity
Another study, which was described in a press release issued August 13, 2012, by the University of California at Davis School of Veterinary Medicine, reported that triclosan “hinders muscle contractions at a cellular level, slows swimming in fish, and reduces muscular strength in mice.” Isaac Pessah, professor and chair of the Department of Molecular Biosciences in the UC Davis School of Veterinary Medicine and principal investigator of the study, said, “These findings provide strong evidence that the chemical is of concern to both human and environmental health.”8
The 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 fibers to contract.8
The team also found that triclosan impairs heart and skeletal muscle contractility in living animals. Anesthetized mice had up to a 25% 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 UC Davis and a study co-author. “Although triclosan is not regulated as a drug, this compound acts like a potent cardiac depressant in our models.”8
Said Hammock: “Triclosan can be useful in some instances, however it has become a ubiquitous ‘value added’ marketing factor that actually could be more harmful than helpful. At the very least, our findings call for a dramatic reduction in its use.”8
FDA Response
It does seem that the FDA is revisiting its official position toward triclosan. In addition to the animal studies showing hormonal effects, the site stated that scientific studies published after FDA review of this ingredient “merit further review,” concluding, “In light of these studies, FDA is engaged in an ongoing scientific and regulatory review of this ingredient. FDA does not have sufficient safety evidence to recommend changing consumer use of products that contain triclosan at this time.”1
Its advice to consumers concerned about this ingredient is to read product labels. “If an over-the-counter drug contains triclosan, it will be listed as an ingredient on the label, in the Drug Facts box. If a cosmetic contains triclosan, it will be included in the ingredient list on the product label.”
However, for consumers, reduction in its use may be easier said than done, as the substance may be difficult to spot in products due to its many aliases, including its chemical designation: 2,4,4’-Trichloro-2’-hydroxydiphenyl ether (CAS#3380-34-5) or trademarked proprietary versions brands such as Microban, Irgasan DP-300, Lexol 300, Ster-Zac, Cloxifenolum, and Biofresh. However, many of the organizations concerned about this chemical offer lists of triclosan-free or triclosan-containing products on their websites.
References
1. Triclosan: What Consumers Should Know. Available at: https://www.fda.gov/forconsumers/consumerupdates/ucm205999.htm. Accessed December 27, 2012.
2. Buehlmann M, Frei R, Fenner L, et al. Highly effective regimen for decolonization of methicillin-resistant Staphylococcus aureus carriers. Infect Control Hosp Epidemiol. 2008;29(6):510-516.
3. National Institute of Environmental Health Science. Tackling Triclosan: Congress Recommends Review Based in Part on SRP Research. Available at: https://niehs.nih.gov/research/supported/dert/cris/programs/srp/phi/archives/publicpolicy/triclosan/index.cfm. Accessed December 26, 2012.
4. Coia JE, Duckworth GJ, Edwards DI, et al. Guidelines for the control and prevention of methicillin-resistant Staphylococcus aureus (MRSA) in healthcare facilities. J Hosp Infect. 2006;63 Suppl 1:S1-44.
5. Triclosan. Beyond Pesticides. Available at: https://www.beyondpesticides.org/antibacterial/triclosan.php. Accessed December 26, 2012.
6. Aiello AE, Larson EL, Levy SB. Consumer antibacterial soaps: effective or just risky? Clin Infect Dis. 2007 Sep 1;45 Suppl 2:S137-47.
7. Antibacterial Soaps: Being Too Clean Can Make People Sick, Study Suggests. Science Daily. Nov. 30, 2010. Available at: https://www.sciencedaily.com/releases/2010/11/101129101920.htm. Accessed December 26, 2012.
8. UC Davis News and Information. Chemical widely used in antibacterial hand soaps may impair muscle function. August 13, 2012. Available at: https://news.ucdavis.edu/search/news_detail.lasso?id=10301. Accessed December 26, 2012.
