News

Plant-based proteins ‘have higher levels of chemical contaminants’ due to processing

Plant-based proteins have higher levels of chemical contaminants than their animal-based counterparts, but there is no suggestion of “immediate risk” to consumers, say scientists.

Research led by the University of Antwerp used liquid chromatography-tandem mass spectrometry to investigate the occurrence of chemicals like organophosphorus flame retardant (PFR) and plasticisers in plant-based alternatives, comparing them to animal-based foods.

Plant-based cheese alternatives showed the highest levels of both total PFRs and plasticisers. Alternatives to meat and fish had lower levels of chemical contamination.

However, compared with previous studies of meat and livestock products, the processed plant-based alternatives generally showed higher contamination levels, leading to a higher dietary exposure in a vegan diet scenario.

“While the adult population is not at immediate risk following NPBF [novel plant-based food] consumption, based on these results, a direct replacement of all ABFs [animal-based foods] with NPBFs is not recommended,” the researchers wrote in the journal Environmental Science & Technology.

Industrial food processing associated with higher levels of chemical contaminants

Plant-based alternatives undergo substantial industrial processing to achieve a comparable texture, taste, and shape of meat or cheese, placing most of them in category 4 (ultra-processed foods [UPFs]) of the Nova classification system, which classifies foods based on the degree of processing used during their manufacturing.

Industrial food processing has been associated with higher levels of chemical contaminants.

The team tested for 17 organophosphates, eight phthalates, and 11 alternative plasticisers. These chemicals are added to materials to enhance their resistance to fire, in the case of PFRs, and to increase product durability, flexibility, and elasticity, in the case of plasticisers.

There is still uncertainty about their toxicity; however, several PFRs and plasticisers have been shown to cause adverse health effects such as neurotoxicity, carcinogenicity, reproductive toxicity, and endocrine disruption, the experts explained.

The 52 products they assessed came from the UK, Germany, and Belgium in 2023 and included a wide range of ingredients, like soya, legumes, seeds, mycoprotein, and nuts.

Food contact material like packaging identified as possible contamination source

The researchers suggested that as well as industrial processing, food contact material like packaging could be another possible contamination source.

The gloves used during food handling are another potential source of chemical contamination.

“While diet is an important pathway for exposure to PFRs and plasticisers, other pathways that can also contribute were not included in this study; it can therefore be assumed that human exposure would increase if multiple pathways were considered, resulting in a higher risk,” they wrote.

The team called for further studies to assess the safety of plant-based food in relation to chemical contaminants.

More products, as well as specific ingredients, should be tested, and doing this at certain stages of the production process would help determine when and where contamination occurs, they argued.

Indeed, many more chemicals, including hazardous ones, can be present in foods due to the migration from food contact materials which were not considered in the authors’ risk assessment, said Lisa Zimmerman, from the Food Packaging Forum, an NGO focused on research into food packaging.

“This is another reason to eat fresh vegetables,” she added.

Processing of food in the spotlight

The health credentials of processed plant-based foods are under scrutiny, and this new research adds another layer of concern.

Previous research has described how UPFs and plastics are intricately linked.

“Evidence linking UPF consumption to deterioration in diet quality and higher risk of chronic diseases is well-established and growing rapidly,” wrote experts in an October 2024 paper for the journal Globalization and Health.

“At the same time, the issue of plastic food contact chemicals (FCCs) is receiving increasing attention among the human health community, as is the generation and dispersion of micro- and nanoplastics.”

Processed plant-based foods are convenient for consumers and commercially attractive for companies. They are not all bad, nor are they all unhealthy.

However, the experts warned that the “intersecting interests and strategies of big food, petrochemical and plastic industries” requires “complementary and coherent government-led statutory regulations” in order to “limit the power of commercial actors profiting from health-harming and environmentally damaging products”.

For example, provisions in food legislation such as requirements to list the chemical constituents of packaging, as well as obligations for reporting chemical presence under substance law regarding the use of plastic materials, would improve traceability of chemicals in plastic products, they added.

This issue will be on the list of priorities as part of talks on a Global Plastics Treaty resume in Geneva this coming August.