Tiny pieces of plastic are now found almost everywhere, from oceans and soil to food, drinking water and the human body.
Scientists are increasingly trying to understand whether these microplastics are simply passing through us or whether repeated exposure could affect our health.
A new study from researchers at Texas A&M College of Veterinary Medicine and Biomedical Sciences suggests that polyethylene, one of the world’s most widely used plastics, may affect the liver.
The researchers found evidence that exposure to polyethylene microplastics can promote changes linked to fatty liver disease and may make the condition worse when combined with an unhealthy diet.
Polyethylene is extremely common in everyday life. It is used in products such as plastic bags, food packaging, wraps, storage containers and some beverage cups, and it accounts for a large share of plastic produced worldwide.
Despite its widespread use, polyethylene has received less attention in health research than several other types of microplastics. It has often been considered relatively inactive in the body, but the new findings suggest that assumption may need closer examination.
The researchers were particularly interested in fatty liver disease, a condition in which too much fat collects inside liver cells. The liver normally performs many essential jobs, including processing nutrients, removing harmful substances from the blood and helping control how the body stores and uses energy.
Fatty liver disease has become increasingly common as obesity, type 2 diabetes and other metabolic problems have risen around the world. In some people, excess liver fat remains relatively mild, while in others it can progress to inflammation, scarring and serious long-term liver damage.
The Texas A&M team examined what happened when experimental models were exposed to polyethylene microplastics. They found that polyethylene alone increased signs associated with fatty liver disease.
The effect became stronger when polyethylene exposure was combined with a diet high in fat, fructose and cholesterol. This type of diet is often used in research to reproduce some of the metabolic stress associated with highly processed Western-style eating patterns.
According to Dr. Adi Joshi, an associate professor at Texas A&M, the results suggest that diet and environmental exposure may work together. A poor diet could already place the liver under stress, while polyethylene exposure may interfere with some of the organ’s normal defense and repair systems.
The researchers then wanted to understand exactly what was happening inside the liver. They worked with scientists at the University of Oklahoma and used an advanced method that allowed them to examine which genes were active in different locations within liver tissue.
This approach gave the researchers a detailed map of the biological changes associated with polyethylene exposure. It allowed them to see not only which cellular signals had changed, but also where those changes were occurring inside the liver.
One important finding involved a protein called PPAR-alpha. This protein helps control how the liver handles fats and energy, and the researchers found that it was involved in the liver’s response to polyethylene microplastics.
The study also pointed to a gene called ANXA2, which has roles in tissue repair and other cell processes. Together, these findings may help explain how polyethylene exposure disrupts normal liver activity and could give scientists targets to investigate in future treatment studies.
The researchers now want to learn whether longer exposure to polyethylene can contribute to more advanced liver disease, including fibrosis, which is the buildup of scar tissue. They also plan to investigate whether changing the PPAR-alpha pathway can reduce some of the harmful effects seen in their experiments.
The study was published in the journal Science Advances. It provides important early evidence that polyethylene should not automatically be viewed as biologically harmless simply because it has traditionally been considered relatively inactive.
However, the findings need to be interpreted carefully. The study identifies a possible biological pathway and shows that polyethylene exposure can worsen liver-related changes under experimental conditions, but it does not establish how much microplastic exposure an average person receives or prove that everyday polyethylene exposure causes fatty liver disease in humans.
Another important limitation is that laboratory exposure does not perfectly reproduce the complicated mixture of plastics, chemicals, foods and other environmental factors people encounter throughout life. Human studies will be needed to determine whether the same liver changes occur at realistic exposure levels and whether some people are more vulnerable than others.
Even so, the research is valuable because it examines a plastic that is extraordinarily common yet comparatively understudied. If future studies confirm these results in humans, reducing microplastic exposure and understanding how it interacts with diet could become another part of efforts to prevent chronic liver disease.
If you care about liver health, please read studies about a diet that can treat fatty liver disease and obesity, and coffee drinkers may halve their risk of liver cancer.
For more health information, please see recent studies that anti-inflammatory diet could help prevent fatty liver disease, and results showing vitamin D could help prevent non-alcoholic fatty liver disease.
Source: Texas A&M University.
