Could your gut help clear out toxic “forever chemicals”?

Scientists are beginning to explore the possibility that certain gut bacteria might help remove per- and polyfluoroalkyl substances (PFAS) – colloquially known as forever chemicals – a class of chemicals linked to cancer and other health harms from the body.

A study published in Nature Microbiology found that certain gut bacteria were able to absorb PFAS, allowing mice with these microbes in their gut to excrete the chemicals through faeces. The findings add to growing interest in how gut microbes could influence the body’s handling of environmental pollutants.

What are PFAS and how do they accumulate in the body?

PFAS are a large class of synthetic chemicals often called “forever chemicals” due to their strong carbon-fluorine bonds, which make them highly resistant to degradation in the body or environment.

“These chemicals have been used since the 1940s across everyday products, from nonstick cookware and food packaging to firefighting foams,” said Uday Nagesh Shivagi, senior consultant and clinical lead in medical gastroenterology at Narayana Health, Bengaluru.

These chemicals primarily enter the body through ingestion of tainted water or contaminated food like fish, meat, or eggs. Inhalation of contaminated dust and skin contact with PFAS containing items are also possible, though less prominent.

Once inside, PFAS bind to serum proteins like albumin and accumulate in organs like the liver and kidneys, as well as in the bile staying in the body for years, explained C. Kolandasamy, senior consultant, department of surgical gastroenterology, Rela Hospital, Chennai. The process of enterohepatic circulation in which substances excreted in bile re-enter the intestines and are reabsorbed into the bloodstream can further prolong their half-life in the body. .

“Some of these chemicals, like PFOS or PFOA, can remain with half-lives of over 8 years,” Dr. Shivagi explained.

Can gut bacteria help eliminate PFAS?

In the recent study , researchers observed that mice carrying specific types of gut bacteria were able to excrete PFAS more effectively through faeces, compared to germ-free mice. “This research gives us early clues about how the gut microbiome might influence PFAS elimination,” Dr. Kolandasamy said. “Certain bacteria appear to bind to PFAS molecules, preventing their absorption and helping excrete them via faeces.”

The mechanism is not one of chemical breakdown, but rather of sequestration, where microbes like Lactobacillus or Bacteroides bind to PFAS in the gut and trap them for elimination. Some microbial metabolites, such as bile acid conjugates, may also play a role in promoting excretion.

“Not all microbes do this,” cautioned Kayalavizhi Jayaraman, consultant gastroenterologist, Prashanth Hospitals, Chennai, “Animal studies have shown that strains like Bacteroides can accumulate PFAS within them. While it’s tempting to think of these microbes as filters, much more research is needed before recommending them for PFAS clearance.” The idea is scientifically compelling but still at a preclinical stage.

“So far, the most convincing data comes from lab and animal studies,” said Dr. Kolandasamy. “Mice with a diverse microbiome show reduced PFAS absorption compared to germ-free mice. However, no human clinical trials have conclusively demonstrated that boosting specific gut bacteria reduces PFAS levels.”

Dr. Jayaraman added that human evidence is mostly observational at this point. “We do see associations between PFAS exposure and gut dysbiosis — meaning changes in microbial diversity, but studies on actively changing the human microbiome to eliminate PFAS are still lacking.”

Role of diet and gut health

While there is no specific diet proven to eliminate PFAS, certain dietary strategies could support the gut’s natural filtering functions.

“Dietary fibre has shown potential,” said Dr. Kolandasamy. “Fiber can bind to bile acids, which also carry PFAS, promoting their excretion. Similarly, probiotics, particularly those containing Lactobacillus strains have shown reduced PFAS absorption in rodent models.”

Pilot studies have also explored the use of bile acid sequestrants such as the cholesterol-lowering drug cholestyramine to lower serum PFAS levels. “These findings suggest gut-focused therapies could be promising in the future,” he added.

Dr. Jayaraman emphasised a preventive approach. “While we don’t yet have a diet protocol to clear PFAS, eating wholesome foods, increasing fibre, and limiting processed and packaged food items may support overall gut health and resilience. It is also wise to avoid non-stick cookware and limit known PFAS exposures.”

Future research

With growing awareness of chemical exposures in everyday life, researchers are exploring whether microbiome-based therapies such as designer probiotics or even faecal microbiota transplantation (FMT) could one day help detoxify environmental chemicals like PFAS.

“There is already interest in engineering bacteria that express PFAS-binding proteins,” said Dr. Kolandasamy. “But these are still early-stage concepts, and there are regulatory and scientific challenges to overcome.”

Aditya Kulkarni, consultant, Paediatric Gastroenterology and Hepatology, Narayana Health SRCC children’s Hospital, Mumbai said “While it’s exciting to imagine a future where a probiotic capsule could help clear toxins, we need years, if not decades of research, to reach that point. Until then, the focus should remain on minimising exposure and supporting gut health naturally.”

This is a field worth watching,” said Dr. Kolandasamy, “but for now, prevention and awareness remain the best defense.”

Published – July 31, 2025 03:16 pm IST

Apple has been accused of exposing users to cancer in a new lawsuit filed in the US that claims that the tech giant’s Watch bands contain high levels of toxic chemicals. According to Daily Mail, the lawsuit claims that Apple’s “Ocean,” “Nike Sport,” and regular “Sport” Watch bands contain high levels of perfluoroalkyl and polyfluoroalkyl substances (PFAS), commonly known as “forever chemicals,” which have been linked to a range of health problems. PFAS chemicals are known for their ability to persist in the human body and environment, earning them their nickname. 

According to the Daily Mail, the lawsuit stems from a recent study on 22 watch bands from various companies in the US. The research found that 15 of the 22 contained harmful PFAS chemicals; among these watches, some were made by Apple. 

The lawsuit, filed in California on Tuesday, specifically alleges that the Sport Band, the Ocean Band and the Nike Sport Band that ships with Nike-branded Apple Watches contain high levels of PFAS. It also alleges that Apple knowingly and willfully did not inform consumers which products contain harmful PFAS, even though the Apple Watch is marketed as a health-promoting device. 

“Instead, in respect of watches, (Apple) continues to hide the existence of PFAS at the point of purchase and otherwise,” the lawsuit states. “(Apple) could have avoided the unreasonable safety and environmental hazard with available manufacturing alternatives, and its failure to do so while continuing to promise consumers health, wellness, and sustainability is unlawful, unfair, and fraudulent under consumer protection laws,” it continues.

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The lawsuit seeks class certification, which is like a mini-trial in which the allegations are examined and argued by each side’s attorneys. It also seeks an injunction to halt the sale of the alleged PFAS-containing watch bands and monetary penalties, the outlet reported. 

Meanwhile, in a statement to Daily Mail, Apple claimed that its Watch bands are safe for users to wear. “In addition to our own testing, we also work with independent laboratories to conduct rigorous testing and analysis of the materials used in our products, including Apple Watch bands,” the tech giant said. 

Apple has also long claimed that its Watch bands are made from fluoroelastomer, a synthetic rubber that contains fluorine but not harmful PFAS chemicals. The company asserts that fluoroelastomer is safe and thoroughly tested to meet health standards.