- A new study of 178 women found that certain kinds of dental floss may expose users to a PFAS chemical.
- PFAS are man-made chemicals used in industry and in consumer products like stain-resistant furniture and non-stick cookware, and they’ve been linked to some health problems.
- According to the study authors, using Oral-B Glide floss was associated with higher levels of one PFAS chemical the body, compared to not using the floss.
- The study also tested 18 brands of floss and found that six contained a chemical the researchers said is a “marker” for PFAS chemicals.
- The researchers wrote that more studies are needed to verify their findings.
People who use certain types of dental floss may be exposing themselves to a toxic chemical, according to a study published Tuesday in the Journal of Exposure Science & Environmental Epidemiology.
The study, led by the Silent Spring Institute and the Public Health Institute in Berkeley, California, tested the blood of 178 women to look for evidence of PFAS, a broad class of man-made chemicals used in industry and in consumer products like waterproof clothing and non-stick cookware.
Because they’re used so widely used — and because most of them don’t break down — PFAS are found in the blood of people across the world, according to the Centers for Disease Control and Prevention (CDC). Some scientific studies have linked exposure to these chemicals with health problems.
A few years after collecting the blood samples, the researchers then asked the women in the study how often they engaged in behaviors that may relate to PFAS exposure, including using non-stick cookware, eating certain packaged foods, buying stain-resistant carpets or furniture, and flossing with Oral-B Glide.
In the paper, the authors wrote that certain flosses including Oral-B Glide “have been reported to be manufactured from PTFE,” though INSIDER was not immediately able to verify the source of such reports. PTFE is a chemical that may be manufactured using PFAS, according to Katie Boronow, study author and senior staff scientist at the Silent Spring Insitute.
(In an email to INSIDER, a spokesperson for Procter & Gamble said the company can “confirm that none of the substances in the report are used in our dental floss.”)
“PFAS are used in a wide variety of products,” Boronow told INSIDER. “And aside from women who are exposed in their workplace or have contaminated drinking water, we don’t really know what the most important sources of exposure are. This study was an effort to uncover and untangle some of these everyday sources of exposure.”
The authors found that having stain-resistant carpet or furniture and living in a city with a PFAS-contaminated water supply were associated with higher levels of some PFAS chemicals in the body. They also found that using Oral-B Glide floss was linked with higher levels of one PFAS called perfluorohexanesulfonic acid (PFHxS) in the body, compared to not using the floss.
The study tested different floss brands for a “marker” of PFAS chemicals
In the second part of the study, the researchers tested 18 floss products for the presence of fluorine, which Boronow said is a “marker” for PFAS chemicals. Some of these products were branded as Oral-B Glide while others had package labels that said “compare to Oral-B Glide,” according to the study.
In total, six products tested positive for fluorine. They were: CVS Health EaseBetween SuperSlip Dental Floss Waxed, Oral-B Glide Pro-Health Mint and Glide Pro-Health Original, Crest Glide Deep Clean Cool Mint Floss, Safeway Signature Care Mint Waxed Comfort Floss, and Colgate Total Dental Floss Mint.
Safeway and Colgate did not immediately respond to INSIDER’s request for comment.
In a statement to INSIDER, CVS Pharmacy said “the CVS brand product that was part of the study was actually discontinued last year and is no longer available in our stores. The product undergoes rigorous safety and quality assurance testing annually and we stand by the safety of our products.”
Procter & Gamble, maker of Crest and Oral-B floss, said in a statement to INSIDER that “the safety of the people who use our products is our top priority. Our dental floss undergoes thorough safety testing and we stand behind the safety of all our products.”
In an interview with BuzzFeed News, Rita Loch-Caruso, a University of Michigan professor of environmental health who wasn’t involved in the study, noted that dental products like floss may contain added fluoride, which also contains fluorine.
“It would have been nice to see them discuss whether fluoride could have been contributing to the fluorine measurements on the floss,” she told BuzzFeed News. (Boronow told BuzzFeed News that none of the products in the study were advertised as containing fluoride.)
There are other possible sources of PFAS
“This study interviewed people about their self-reported use of a wide array of consumer products and foods, it was not focused on dental floss alone,” the Procter & Gamble spokesperson added in an email to INSIDER. “Additionally, in the supplemental table, the dental floss data alone showed no correlation to these substances. It was only when trying to combine consumer products that they saw any correlations at all.”
In response, Boronow said that, in the final paper, the authors used a statistical model that “looked at the effect of floss taking into account the other behaviors that the women reported doing as well.”
The researchers also wrote this is the “first evidence” that using PTFE-based dental floss may contribute to higher PFAS levels in the body, and added that more studies are needed to verify their findings.
Harvard University environmental health professor Philippe Grandjean, who was not involved with the study, told BuzzFeed News that the study participants may also have been exposed to PFAS chemicals from other sources that weren’t included in the research.
A handful of US communities have water sources that are contaminated with dangerously high levels of PFAS, for example, and people may also be exposed if they accidentally swallow contaminated dirt or dust or eat seafood caught in contaminated water. The chemicals can also show up cosmetics, firefighting foams, and some food packaging, like pizza boxes and microwave popcorn bags.
Boronow acknowledged this.
“Certainly our study only looked at a subset of all possible sources [of PFAS exposure],” she told INSIDER.
Concern over PFAS exposure stems from the fact that the chemicals can accumulate and stay in the body for long periods of time, and because buildup of PFAS in the human body has been linked to different health conditions, including low birth rates, high cholesterol, liver damage, chronic kidney disease, asthma, and colon ulcers.
The International Agency for Research on Cancer and the US Environmental Protection Agency (EPA) think PFAS may be cancer-causing, too, because higher-than-average exposures to the chemicals have been linked to higher rates of testicular and kidney cancers, Business Insider reported last year. But that link hasn’t been demonstrated for sure.
For now, the CDC says that more studies are needed to gain a better understanding of the effects of PFAS exposure.
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