Tech & Science

Is Cancer Lurking in Your Toothpaste? (And Your Soap? And Your Lipstick?)

09_04_Colgate_01
09/26/14
In the Magazine
Colgate Total contains the antibacterial agent triclosan Andrew Harrer/Bloomberg/Getty

Since cancer seems to be an ever-present enemy, we greet the appearance of its lethal emissaries in prosaic objects with a morbid lack of surprise: carcinogens lurk in coffee, hamburgers, rugs, dry-cleaned clothes, even peanut butter. And it may apparently reside in one of the most popular toothpastes on the market, a toothpaste you’ve probably thrown into your own shopping cart with nary a second thought.

The possible culprit is the germicide triclosan, found in Colgate Total, the widely-used brand manufactured by Colgate-Palmolive. Introduced in 1997, the manufacturer claims that it is the “only toothpaste approved by the FDA to help fight plaque and gingivitis” by blasting the teeth and gums with triclosan.

The claim is at least partly true: no other toothpaste in the United States contains triclosan, though plenty of antibacterial soaps and cosmetics count it as an ingredient. It is that bacteria-fighting capability that has recently raised questions about Colgate Total’s safety, as well as about whether the Food and Drug Administration knuckled under and did not heed warnings about the compound.

Triclosan is a chlorinated aromatic compound: very basically, two benzene rings (a sturdy hydrocarbon, with six atoms of carbon and hydrogen each) linked by an oxygen atom, with three chlorine atoms protruding like spokes, as well as a lone hydroxyl group (oxygen + hydrogen). First used in the 1970s in hospitals, it has since become a widespread antimicrobial agent. Not only is triclosan present in Colgate Total and many household soaps, but it can also be found in coolers, odor-protected shoes and makeup, according to Mae Wu, a lawyer with the Natural Resources Defense Council. She says that triclosan is “all over the place,” even if, as she notes, we had “been doing fine without it” for several centuries of human-microbial cohabitation of the planet.

“Triclosan is 110 percent marketing,” says Michael Osterholm, who heads the Center for Infectious Disease Research and Policy at the University of Minnesota. Osterholm, who helped Minnesota become the first state to ban most uses of triclosan. He told me the compound has been superseded by superior, safer antimicrobial agents, and Procter and Gamble has begun advertising its Crest toothpaste as being “100% triclosan free.” That may also be a triumph of marketing, but one that could lead more people to question the presence of triclosan in household items, thereby forcing Colgate’s hand.

“They understand that the public is getting this,” Osterholm says of the Crest claim.

“Triclosan isn't an essential ingredient in many products,” writes Dr. James M. Steckelberg of the Mayo Clinic. “While triclosan added to toothpaste has been shown to help prevent gingivitis, there's no evidence that antibacterial soaps and body washes containing triclosan provide any extra benefits, according to the Food and Drug Administration.” On its website, the FDA says that soaps that contain antibacterial compounds like triclosan have not been shown to be “any more effective at preventing illness than washing with plain soap and water.” The FDA stops well short, however, of calling triclosan a danger, merely suggesting that consumers think twice about buying products that contain it.

Earlier this summer, the Society for Healthcare Epidemiology in America, whose mission is to prevent hospital infections, made a blunt recommendation to doctors in its guidelines for hospital hygiene: “Do not use triclosan-containing soaps.” Those guidelines also cite “concerns about the potential human and environmental impacts of this chemical” and suggest, instead, the use of alcohol-based hand rubs.

The FDA first promised to look at triclosan in handsoap in 1974. Four decades later, that study remains incomplete, though it will reportedly be released in 2016.

Meanwhile, most people are absorbing triclosan whether they know it or not. Triclosan is nearly ubiquitous, easily entering the body by ingestion or through the skin. The Centers for Disease Control and Prevention tested 2,517 people in 2003 and found that almost three-fourths had triclosan in their urine. Toothpaste is an especially potent triclosan-delivery vehicle. “People who brushed their teeth with Colgate Total had more than five times as much triclosan in their urine as people who didn’t use it,” Wu wrote in an NRDC blog post.

Far less clear is what triclosan does (or doesn’t do) to the human organism. For example, a review by scientists at the University of California at Davis concluded that when it comes to triclosan and triclocarban, a chemically related antibacterial agent, “the benefits may not be worth the risks.” The researchers wrote that triclosan and triclocarban could cause neural and cardiac ailments, though they also conceded that “the research is in its early stages."  

Other recent research suggests that triclosan could cause breast cancer, though the results were gleaned from exposure in mice. Triclosan’s effects on the endocrine system, which delivers hormones throughout the body, are also increasingly thought to be harmful; a 2006 study of bullfrogs and tadpoles exposed to triclosan in aquatic environments found that “exposure to low levels of triclosan disrupts thyroid hormone-associated gene expression and can alter the rate of thyroid hormone-mediated postembryonic...development.” If triclosan does turn out to be an endocrine disruptor, that would make young children, infants and pregnant women especially vulnerable. (There are also concerns about the accumulation of triclosan in waterways, where its build-up could “disrupt aquatic life by changing native bacterial communities,” according to aquatic ecologist Emma Rosi-Marshall.)

And though the FDA is now urging Americans to think about their triclosan consumption, the agency didn’t seem nearly as concerned with the issue 17 years ago, when it declared Colgate Total ready for supermarket shelves. In 2010, the Natural Resources Defense Council sued the FDA for access to documentation regarding Colgate Total’s approval; the documents, totalling 35 pages, had never been seen by the public before.

Bloomberg News had three scientists examine the FDA’s approval of Colgate Total. “The recently released pages, taken alongside new research on triclosan, raise questions about whether the agency did appropriate due diligence in approving Total 17 years ago, and whether its approval should stand in light of new research,” Bloomberg concluded in its extensive investigation.  

“The literature is all over the place,” admits Rear Admiral Sandra L. Kweder, who is the deputy director of the FDA’s office of new drugs. She says that the burden is on soap manufacturers to show that their product is safe and efficient.

Industry lobbyists do have complexity on their side: given the number of chemicals to which the average person is exposed, and the genetic disposition some people have to cancer, it is exceedingly difficult to make a direct epidemiological correlation between household products and incidences of cancer. Even with well-known villains like bisphenol-A (BPA) and phthalates, the science remains in dispute.

Some aren’t waiting for a resolution that could come in the distant future. Earlier this year, Minnesota became the first state to prohibit usage of triclosan, though FDA-approved products like Colgate Total are outside the purview of the ban, which doesn’t take effect until 2017.   

Colgate-Palmolive says its product is safe. Patricia Verduin, Colgate-Palmolive’s head of research and development, sent me an extensive rebuttal of several studies that seem to show triclosan’s potential dangers. She noted that 90 studies, involving a total of 20,000 people, have made Colgate Total “the most extensively tested and reviewed  toothpaste in the world.” She added that studies linking the compound to cancer and thyroid problems “use excessively high levels of triclosan — in some instances, thousands of times greater than the level of exposure from use of consumer products.” Verduin also pointed out that “regulatory authorities around the world… affirm that triclosan as used in consumer products is not a human carcinogen or endocrine disruptor.”

And in an op-ed she wrote for Fox News, Verduin maintains that “[r]ecent claims that triclosan in Colgate Total can lead to cancer are absolutely untrue.” She discounts findings about triclosan’s potential endocrine disruption as “rumors.”

Yet if the battle over BPA (which also has its defenders) is any indication, triclosan will probably meet with a rising tide of public suspicion, and more and more products will appear with green stickers proclaiming themselves triclosan-free, as Crest already does. Many major corporations have removed triclosan from soaps and cosmetics. Others will likely follow, if for no other reason than for an image of healthful living.

Triclosan may be falling out of favor, but, for some, the underlying concern is that of federal regulators too easily convinced by science done not in the public interest, but for the sake of corporate gains. Writing last year in a New York Times op-ed, investigative reporter Ian Urbina noted that federal regulators effectively allow industry to police itself, so that few of the 85,000 industrial chemicals in use today — including the ones on your bathrooms shelves — have passed unbiased governmental inspection. “Unlike pharmaceuticals or pesticides,” Urbina writes, “industrial chemicals do not have to be tested before they are put on the market. Under the law regulating chemicals, producers are only rarely required to provide the federal government with the information necessary to assess safety.”

But for others, the chemicals aren’t dangerous if used with moderation. Dr. Bruce D. Hammock, for example, runs the Laboratory of Pesticide and Biotechnology at UC Davis and was one of the investigators involved in the study on triclosan and triclocarban. “There are real risks to triclosan,” Hammock says. “And there are real benefits.” He welcomes more research into its effects on the human body.

Hammock calls triclosan “quite a good antimicrobial” that belongs in the hospital, not on the kitchen counter. “There’s no reason for it to be there,” he says of its inclusion in hand and dish soaps.

Toothpaste is another matter, and Hammock points out that the concentration of triclosan is low in Colgate Total, while, at the same time, the incidence of gingivitis is high enough to warrant the compound’s inclusion. Hammock adds that he is happy with his toothpaste of choice: Colgate Total.

Regulators share his confidence. Jeff Ventura, a press officer for the FDA, sent me a statement asserting that “based on the scientific evidence, in this case, the balance of benefit and risk has been shown to be favorable for [Colgate Total].” The statement does also say, however, that “use of an ingredient may be acceptable for one product but not for another,” thus perhaps opening the way for a ban of triclosan in soaps. After all, federal regulators can’t ignore growing concerns buttressed by mounting evidence.

Asked if the FDA would revisit its approval of Colgate Total, Dr. Kweder hesitates.

“1997 was a long time ago,” she says. 

Correction: An earlier version of this article inaccurately characterized the conclusions of researchers at the University of California at Davis. That study did not implicitly point to a link between triclosan and cancer.

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