The world's most widely used plastic may be doing more than polluting oceans and waterways. Researchers at Texas A&M University have found evidence that tiny particles of polyethylene—the plastic commonly used in food packaging, plastic wraps, storage containers and beverage cup linings—could contribute to fatty liver disease and make the condition worse when combined with an unhealthy diet.

The findings are drawing attention because polyethylene accounts for about one-third of global plastic production but has received far less scientific scrutiny than other microplastics. The study suggests that everyday exposure to this plastic, alongside diets rich in fat, sugar and cholesterol, may increase the risk of liver damage, although experts caution that more human studies are needed.

"No studies have really looked into polyethylene's effect on liver health, and it's the most widely produced plastic," said Dr Adi Joshi, associate professor in the Department of Veterinary Physiology and Pharmacology at Texas A&M College of Veterinary Medicine and Biomedical Sciences. "What we now know is that these microplastics, especially polyethylene, affect our liver's natural defence and repair mechanisms."

Fatty liver disease, in which excess fat builds up inside liver cells, affects around one in four people worldwide, according to the American Liver Foundation. In laboratory research, the Texas A&M team found that polyethylene exposure alone increased signs of fatty liver disease. The damage became more severe when the plastic was combined with a diet resembling a typical Western eating pattern.

"Those who have a more Western-style diet, including foods like burgers and sodas, may have a greater chance of progressing to fatty liver disease if they are also exposed to polyethylene," Joshi said.

To understand how the damage occurs, researchers collaborated with the University of Oklahoma and used spatial transcriptomics, a technique that shows which genes are active while preserving the exact location of cells within tissue. The approach revealed that polyethylene-activated PPAR-alpha, a protein that regulates how the liver processes fats, and highlighted ANXA2, a gene involved in repairing damaged tissue, as another possible contributor to disease.

"This is the pioneering study showing that polyethylene can contribute to fatty liver disease, and the use of spatial transcriptomics has determined exactly where the damage has happened within the liver," Joshi said. "The other microplastics might also be harmful to the liver, and we definitely need to look into other classes of microplastics."

Microplastics have already been detected in oceans, drinking water, food, air and human tissues. Previous studies published in journals including Environmental Science & Technology and Science of the Total Environment have linked microplastic exposure with inflammation and oxidative stress, but direct evidence that these particles cause liver disease in humans remains limited. The new findings add an important biological clue but are based on preclinical research, meaning larger human studies will be needed before firm conclusions can be drawn.