A Canadian clinical study found that adult men commonly carry detectable levels of a wide range of per- and polyfluoroalkyl substances in their blood, including long- and short-chain compounds as well as replacement chemicals like GenX.
Researchers also assessed whether an oat fiber supplement could help reduce these concentrations
Using serum samples collected from 2019 to 2020, the researchers analyzed blood samples from 72 male participants in Toronto enrolled in a cholesterol-lowering trial. The participants were tested for 17 types of per- and polyfluoroalkyl substances (PFAS). Over a 4-week intervention, half consumed oat beta-glucan fiber three times daily, whereas the rest received a rice-based placebo.
At baseline, perfluorooctanesulfonamide (PFOSA), perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorohexane sulfonic acid (PFHxS) showed the highest average concentrations. PFOSA had the highest geometric mean at 7.1 ng/mL and was detected in all samples. All participants had PFAS levels above the U.S. National Academies of Sciences, Engineering, and Medicine (NASEM) threshold for clinical monitoring. Further, 7% of them had total PFAS concentrations exceeding 20 ng/mL, the level at which further screening for thyroid, kidney, and testicular conditions is advised.
Short-chain PFAS, perfluorobutanoic acid (PFBA), and perfluorohexanoic acid (PFHxA) were also found in all participants. GenX, a newer replacement chemical, was detected in 71% of samples.
After the intervention, total PFAS concentrations declined in both groups. However, only the oat beta-glucan group showed a significant reduction in the PFAS identified by NASEM as clinically relevant, driven mainly by decreases in PFOA and PFOS.
The researchers also evaluated clinical biomarkers. PFBA, PFHxA, perfluorodecanoic acid, and PFOSA were associated with higher gamma-glutamyl transferase (GGT), a liver enzyme linked to hepatocellular stress. PFHxA and PFHxS were also associated with elevated alanine aminotransferase (ALT). No statistically significant associations were observed with aspartate aminotransferase (AST).
Although no consistent associations were found between PFAS and cholesterol levels, PFHxA and perfluoroheptanoic acid were linked to slightly higher high-density lipoprotein cholesterol.
The researchers suggested that dietary fiber may reduce PFAS reabsorption in the gut, similar to how it reduces bile acid recirculation. However, they noted that the short duration of the intervention and uncontrolled PFAS exposures during the study may have limited the observed effects. Longer studies with larger samples are needed to determine whether dietary fiber can effectively lower PFAS body burden.
Disclosures can be found in the published study.
