Researchers find gut bacteria rapidly soak up ‘forever chemicals’

Can our gut bacteria help clear dangerous ‘forever chemicals’ from our bodies? New research reveals certain microbes rapidly sequester PFAS, offering hope for microbiome-based solutions against toxic environmental exposures.

Study: Human gut bacteria bioaccumulate per- and polyfluoroalkyl substances. Image Credit: New Africa / Shutterstock

Scientists have discovered that certain species of microbe found in the human gut can bioaccumulate (store internally rather than merely absorb) PFAS – the toxic and long-lasting 'forever chemicals.' They say boosting these species in our gut microbiome could potentially help increase faecal excretion of some PFAS, but direct evidence of health protection in humans is not yet available. The research is published in the journal Nature Microbiology.

PFAS have been linked with a range of health issues, including decreased fertility, developmental delays in children, and a higher risk of certain cancers and cardiovascular diseases.

Scientists at the University of Cambridge have identified a family of bacterial species, naturally found in the human gut, that can bioaccumulate various PFAS molecules within their cells. The study showed that when a community of 20 human gut bacterial strains (“Com20”) was introduced into the guts of mice to 'humanise' the mouse microbiome, these bacteria collectively rapidly accumulated PFAS eaten by the mice, which were then excreted in faeces. The researchers also performed a separate comparison using communities containing either five high-accumulating or five low-accumulating strains.

The researchers also found that as the mice were exposed to a single oral dose of PFAS, the microbes in the colonized mice contributed to increased faecal excretion of PFAS compared to germ-free controls. The finding that gut bacteria sequester a consistent fraction of PFAS across a range of concentrations comes from in vitro experiments with B. uniformis, not from the mouse model. Within minutes of exposure, the bacterial species tested in laboratory (in vitro) kinetic studies bioaccumulated between 25% and 74% of the PFAS. This rapid uptake was demonstrated in cell cultures, whereas the 25–74% range was observed in a 24-hour screen across different strains.

The results are the first evidence that our gut microbiome may play a beneficial role in removing toxic PFAS chemicals from the body, although this has not yet been directly tested in humans. The study only demonstrated increased faecal excretion in mice colonised with human gut bacteria, and did not assess PFAS levels in blood or measure health effects.

The researchers plan to utilize their discovery to develop probiotic dietary supplements that enhance the levels of these beneficial microbes in the gut, potentially protecting against the toxic effects of PFAS. However, further research, including human cohort studies, will be necessary to determine whether this strategy can effectively reduce PFAS levels and associated health risks in people.

PFAS (Perfluoroalkyl and Polyfluoroalkyl Substances) can't be avoided in our modern world. These man-made chemicals are found in many everyday items, including waterproof clothing, non-stick pans, lipsticks, and food packaging, which are used for their resistance to heat, water, oil, and grease. However, because they take thousands of years to break down, they accumulate in large quantities in the environment and in our bodies.

Dr Kiran Patil, in the University of Cambridge's MRC Toxicology Unit and senior author of the report, said: "Given the scale of the problem of PFAS 'forever chemicals', particularly their effects on human health, it's concerning that so little is being done about removing these from our bodies. We found that certain species of human gut bacteria have a remarkably high capacity to soak up PFAS from their environment at a range of concentrations, and store these in clumps inside their cells. Due to aggregation of PFAS in these clumps, the bacteria themselves seem protected from the toxic effects."

Dr Indra Roux, a researcher at the University of Cambridge's MRC Toxicology Unit and a co-author of the study, said: "The reality is that PFAS are already in the environment and our bodies, and we need to try and mitigate their impact on our health now. We haven't found a way to destroy PFAS, but our findings open the possibility of developing ways to get them out of our bodies where they do the most harm."

There is increasing concern about the environmental and health impacts of PFAS, and in April 2025, the UK launched a parliamentary inquiry into their risks and regulation.

There are over 4,700 PFAS chemicals in widespread use. Some substances are cleared out of the body through our urine in a matter of days, but others with a longer molecular structure can remain in the body for years.

Dr Anna Lindell, a researcher at the University of Cambridge's MRC Toxicology Unit and first author of the study, said: "We're all being exposed to PFAS through our water and food – these chemicals are so widespread that they're in all of us.

"PFAS were once considered safe, but it's now clear that they're not. It's taken a long time for PFAS to become noticed because at low levels they're not acutely toxic. But they're like a slow poison."

Lindell and Patil have co-founded Cambiotics, a startup, along with serial entrepreneur Peter Holme Jensen, to develop probiotics that remove PFAS from the body. They are investigating various ways to turbocharge the microbes' performance. Cambiotics is supported by Cambridge Enterprise, the innovation arm of the University of Cambridge, which helps researchers translate their work into a globally leading economic and social impact.

While the new findings show that certain gut bacteria can accumulate PFAS in the lab and animal models, not all gut bacteria are capable of doing so. The study found that some species, particularly Gram-negative strains, are high accumulators, while others are not. The experiments primarily focused on one PFAS (PFNA), so the effects may differ for other PFAS compounds.

While we wait for new probiotics to become available, the researchers suggest that the best things we can do to protect ourselves against PFAS are to avoid PFAS-coated cooking pans and use a reliable water filter.

The authors also caution that further research is needed to determine whether increasing PFAS-bioaccumulating gut bacteria will significantly reduce PFAS levels or health risks in humans. Further human studies are planned to clarify this potential.

The study also identified mechanistic details, including the role of bacterial efflux pumps (such as TolC in E. coli) and the intracellular aggregation of PFAS, visualized via cryogenic FIB-SIMS imaging. Longer-chain PFAS (such as PFDA) were found to be more efficiently bioaccumulated than shorter-chain variants.