Eating more fiber could help reduce the amount of forever chemicals in your blood, study finds

Research estimates that 200 million people in the U.S. rely on tap water contaminated with PFAS, or forever chemicals. This class of chemicals includes more than 9,000 potentially hazardous synthetic compounds linked to cancer and endocrine disruption—and they have become ubiquitous, lurking in everything from non-stick pans to plastic food containers and even beer.

PFAS have earned the nickname forever chemicals because of their resistance to breaking down—both in the environment and the human body. With greater exposure, these chemicals bioaccumulate, leading to higher concentrations in our bodies, soil, and water. While there aren’t many interventions to reduce PFAS in the body, scientists in Canada may have unearthed a potential breakthrough.

A small study from March published in the journal Environmental Health revealed that people who consumed a fiber supplement had reduced concentrations of specific types of PFAS chemicals. To investigate PFAS exposure, researchers used blood serum samples—the fluid in blood leftover after the removal of blood cells and clotting factors—from 72 adult males with high cholesterol that were collected in 2019 to 2020 as part of a clinical trial investigating dietary fiber intervention to reduce blood cholesterol.

Researchers chose to look at those with high cholesterol because it is well-supported that PFAS exposure can increase total and LDL (bad) cholesterol. They found that all of the participants had at least six different types of PFAS chemicals present in their blood.

The participants were split into two groups: a placebo group and one that took fiber supplements for four weeks in the form of an oat-derived beta glucan—a type of soluble fiber found in foods like oats, barley, and mushrooms—beverage taken three times a day.

At the end of four weeks, all participants had lower levels of PFAS, but researchers noticed that for those taking the fiber supplement, there were specific PFAS chemicals that were drastically reduced after the intervention.

Those chemicals (PFOA, PFNA, PFDA, PFUnDA, PFHxS, PFOS, and MeFOSSA) are considered long-chain, which are more persistent in the environment and our bodies, making it significant that a fiber intervention could reduce their concentrations.

How could fiber reduce PFAS chemicals?

Several studies have already established a link between consuming fruits, vegetables, and fiber-rich diets and lower PFAS concentrations in both adults and children. But what kind of role does fiber play?

In the recent study, researchers explain that dietary fibers could impede the absorption or reabsorption of PFAS by forming a gel that lines the gut and traps substances like bile acid—which has a similar chemical structure to PFAS. These gel-forming fibers are commonly found in foods like oats and barley.

Study limitations

Researchers caution that there are limitations to this study: the sample size was fairly small and the timeframe of the intervention was short at only four weeks.

“Many long-chain PFASs have half-lives on the order of 2–7 years, thus a one-month intervention may be insufficient to strongly influence serum-PFAS concentrations with ongoing exposure,” the authors wrote.

Additionally, the samples used were originally collected as part of a study meant to observe changes in cholesterol, not PFAS. “There was no information collected on potential sources of PFAS exposure prior to or during the study and no attempt to control for differences in ongoing exposures between intervention and control groups,” the researchers explained.

The study authors also pointed out that future studies need to test if higher concentrations of the fiber supplement could lead to greater reductions in PFAS levels. But despite the limitations, the authors are hopeful—eating more fiber could present a practical and feasible way to reduce the amount of forever chemicals in our bodies, and the toll that they take.

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