Polish Study Finds PFAS in All Tested Commercially Available Plant-Based Protein Supplements
Need to Know
- PFAS were detected in all five plant-based protein supplement types tested and were the dominant contributors to estimated cumulative non-carcinogenic risk, with rice protein producing the highest PFAS hazard quotient
- Other contaminants were also detected, including mycotoxins, neonicotinoid pesticides, PAHs, and 5-HMF; certain findings indicated potential concerns under the study’s screening-level risk assessments
- The researchers called for systematic monitoring of emerging contaminants and emphasized multi-contaminant risk assessment, while noting that the small sample size and exposure assumptions limit the findings’ generalizability.
A study of commercially available plant-based protein supplements detected multiple classes of chemical contaminants, with per- and polyfluoroalkyl substances (PFAS) identified as the primary contributor to estimated cumulative non-carcinogenic risk.
Published in NFS Journal and conducted by the University of Warmia and Mazury in Olsztyn and the University of Agriculture in Krakow, Poland, the study analyzed protein isolates derived from soy, rice, pea, hemp, and pumpkin seeds for PFAS, mycotoxins, pesticides, polycyclic aromatic hydrocarbons (PAHs), and the processing contaminant 5-hydroxymethylfurfural (5-HMF). The researchers aimed to characterize the co-occurrence of contaminants representing environmental contamination, agricultural residues, natural toxins, and industrial processing.
The products were obtained from retail distribution in Olsztyn, Poland. For the exposure assessment, the researchers assumed consumption of 30 grams of protein supplement per day by a 70-kilogram adult.
PFAS Drove Estimated Cumulative Risk
PFAS were detected in all five protein supplement types, with total concentrations ranging from approximately 724–3,010 nanograms per gram (ng/g). Soy protein contained the highest total PFAS concentration, followed by rice protein, while pumpkin seed protein contained the lowest.
Perfluorohexanoic acid (PFHxA) was the predominant PFAS across the samples, reaching 2,877 ng/g in soy protein.
Rice protein produced the highest PFAS hazard quotient (HQ) because the researchers' risk characterization was based on the sum of PFOA, PFOS, PFNA, and PFHxS, rather than total PFAS concentrations.
Across all five protein types, PFAS-related HQs ranged from approximately 32–260. The researchers emphasized that the European Food Safety Authority (EFSA) group-based approach used in the assessment was developed primarily for foods of animal origin and has not been specifically validated for plant-based protein isolates. Therefore, the estimates were described as preliminary comparative indicators rather than definitive measures of health risk.
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When the researchers combined contaminants with established health-based guidance values into a total hazard index (HI), values ranged from 32.15 for hemp protein to 260.74 for rice protein. PFAS accounted for most of the calculated cumulative non-carcinogenic risk.
Mycotoxins, PAHs, Pesticides, and 5-HMF Were Also Detected
Additonally, seven of eight targeted mycotoxins were detected. Deoxynivalenol (DON), HT-2 toxin, T-2 toxin, and fumonisins occurred in all five supplement types, while aflatoxin B1 was not detected. Most individual mycotoxin HQs remained below 1; however, the combined HQ for T-2 and HT-2 toxins slightly exceeded 1 in pea protein.
Ochratoxin A (OTA) was detected in all five products, reaching its highest concentration in rice protein at 6.15 micrograms per kilogram (μg/kg), which exceeded the 5 μg/kg EU limit cited by the researchers. Rice and pea protein also produced OTA margins of exposure below the EFSA precautionary threshold used in the study.
Among 56 pesticides assessed, none were detected except the neonicotinoids clothianidin and thiamethoxam, and at low levels of non-carcinogenic risk.
PAHs ranged from undetectable concentrations in pea protein to 137 μg/kg in pumpkin seed protein. Only the low-molecular-weight PAHs naphthalene, acenaphthylene, and fluorene were detected; no high-molecular-weight or regulated marker PAHs were found. Screening-level estimates of lifetime cancer risk exceeded the study's risk-management threshold for hemp and pumpkin seed proteins, although the researchers cautioned that their assessment applied a conservative cancer slope factor to total PAHs.
Finally, 5-HMF varied substantially among products. Pea protein contained 369.16 milligrams per gram (mg/g), approximately 85 times the level in soy protein and 128 times the level in rice protein. Under the study's screening approach, estimated exposure from pea protein exceeded the animal-derived no-observed-adverse-effect level used by the researchers, resulting in an HQ of 1.98. The authors noted that the estimate should be interpreted cautiously because no acceptable or tolerable daily intake has been established for 5-HMF.
Researchers Call for Broader Monitoring
The researchers concluded that plant-based protein supplements may contain chemical contaminants arising from environmental exposure, agricultural practices, and processing. They called for systematic monitoring of emerging contaminants, improved control of environmental contamination, and optimization of processing conditions to reduce thermal process contaminants.
However, the authors acknowledged that the study included only five commercially available protein supplements and represented a limited geographic and temporal market snapshot. The exposure assessment also did not account for gastrointestinal bioaccessibility, potentially overestimating systemic exposure. They recommended studies involving more products and contaminant groups to determine whether the observed patterns hold across brands and production technologies.
