Plastic exposure damages metabolic function for two generations, find researchers

31 Jan 2023 --- Researchers from the University of California Riverside (UCR), US, found that fathers exposed to chemicals in plastics can affect the metabolic health of their offspring for two generations.

The researchers used mice as test subjects to find that paternal dicyclohexyl phthalate (DCHP) exposure for four weeks led to high insulin resistance and impaired insulin signaling in F1 (first) offspring. The same but weaker effect was seen in F2 (second generation) offspring.

“The main conclusion of our research was that paternal exposure to the endocrine-disrupting chemical DCHP, a phthalate commonly found in plastics, can lead to intergenerational and transgenerational adverse effects on the metabolic health of offspring,” Jingwei Liu, an author of the study and member of the division of biomedical sciences, school of medicine at UCR, tells PackagingInsights.

“Our study also found that paternal DCHP exposure can lead to sex-specific transgenerational effects on the metabolic health of offspring. It is surprising to see that such a chemical-induced effect can be transmitted through generations.”

Study finds paternal mice pass down insulin resistance for two generations after plastic chemical exposure. The cost of plastic chemicals 
If DCHP is exposed to paternal mice for four weeks, the chemical can have implications for two generations. The effect is for the father and multi-generational offspring to have issues controlling their insulin and elicited sperm tsRNA/rsRNA changes. 

“This work also strengthened the theory that environmental factors, such as toxin exposure, can alter the epigenetic information carried in sperm,” Junchao Shi, an author of the study and postdoctoral scholar at UCR, tells PackagingInsights.

According to the study, phthalate exposures are associated with cardiometabolic mortality in humans, resulting in societal costs of approximately US$39 billion per year or more.

Changcheng Zhou, lead author, and professor of biomedical sciences in the School of Medicine, UCR, stresses that the impact of exposure to DCHP on human health is not well understood, even though DCHP is widely used in a variety of plastic products and has been detected in food, water and indoor particulate matter.

DCHP has also been found in human urine and blood samples. The US Environmental Protection Agency recently designated DCHP as one of 20 high-priority substances for risk evaluation.

Disrupting chemicals in plastic
The researchers explain that exposure to ubiquitous plastic-associated endocrine-disrupting chemicals (EDCs) increases the risk of many chronic diseases. This was demonstrated through several widely used plastic-associated EDCs increasing cardiometabolic disease in appropriate mouse models. DCHP research shows potential harmful effects for human health. 

“We hope our work can attract more attention from the public and make people aware of the potential risks of using plastic products,” Shi continues.

These EDCs include bisphenol A and related chemicals, flame retardants, phthalates, per- and polyfluoroalkyl substances (PFAS). Plastic base chemical bisphenol A (BPA), and many phthalate plasticizers, are associated with increased metabolic disease risk in humans.

Similarly, parental exposure to EDCs has been shown to cause metabolic disorders, including obesity and diabetes, in offspring. However, little is known about the effects of paternal EDC exposure to date.

Liu acknowledges that the effects of BPA have been extensively studied and widely reported so people may know the risk of using BPA-containing products, but still little is disclosed and publicly spread about other harmful chemical additives. 

“It is likely that many people are not fully aware of the specific harmful ingredients in plastics, such as endocrine-disrupting chemicals. However, research progress is still limited for a wide variety of plasticizers. Their safety is not well understood, especially in terms of the effects on long-term health,” adds Liu. 

“It’s best to minimize our use of plastic products. This can also help reduce plastic pollution, one of our most pressing environmental issues,” concludes Zhou.

By Sabine Waldeck