One of the most widely used plastics globally, found in food packaging, plastic wraps, storage containers, and takeaway cups, might be contributing to the risk of fatty liver disease.
This disease, as recognized today, was first identified in 1980. However, since the 19th century, physicians have observed a connection between diet and fatty infiltration of the liver, even before formal studies were conducted.
A recent mice study suggests that modern food conveniences could exacerbate this issue.
Many people are unaware they have non-alcoholic fatty liver disease until it is inadvertently discovered during scans for other conditions.
When symptoms do arise, they can include fatigue, a general feeling of being unwell, and discomfort on the right side under the ribs.
Excess fat accumulation in liver cells can lead to inflammation, fibrosis (scar tissue build-up), and potentially cirrhosis (severe damage) if untreated.
Your risk of fatty liver disease increases if you are overweight, particularly around the abdomen.
Additional risk factors include high blood fat levels (LDL cholesterol or triglycerides), type 2 diabetes or prediabetes, and high blood pressure.
While these risk factors involve diet and metabolism, a recent mouse study reveals another overlooked dietary component: microplastics exposure, especially polyethylene.
Polyethylene is a crucial plastic for food convenience, used for packaging takeaways, wrapping leftovers, and preventing single-use cups from disintegrating.
Compared to other polymers, polyethylene has been viewed as less concerning.
“No studies have really looked into polyethylene’s effect on liver health, and it’s the most widely produced plastic,” says molecular pharmacologist Adi Joshi from Texas A&M University.
“What we now know is that these microplastics, especially polyethylene, affect our liver’s natural defense and repair mechanisms.”
Joshi and his team’s research, published in Science Advances, is based on mouse experiments, so further studies are needed to determine if polyethylene has similar effects on human livers.
Although the study involved a small sample size, the findings were nonetheless concerning.
Twenty male mice were organized into four groups.
Groups 1 and 2 received standard lab mouse chow, while groups 3 and 4 were given a high-fat, high-sugar, and high-cholesterol diet, known to induce metabolic dysfunction-associated steatohepatitis (MASH), a type of fatty liver disease.
The researchers also administered a daily dose of water with two milligrams of polyethylene particles, measuring 10 to 150 nanometers, to the mice in groups 2 and 4.
After eight weeks of treatment, the mice were euthanized, and their blood serum and livers were examined.
The results indicate that microscopic polyethylene can trigger symptoms of fatty liver disease, even with a standard diet.
As anticipated, the two groups of mice on the MASH diet showed significantly higher levels of fatty liver disease indicators than those on the standard chow.
Nevertheless, regardless of diet, the presence of microplastics seemed to worsen the condition, even in mice on a relatively healthy diet.
Both groups that consumed microplastics had elevated levels of ALT, an enzyme indicative of liver issues, and liver triglycerides compared to those fed the same diet without polyethylene.
Similarly, liver cell inflammation, ballooning, and steatosis (fat accumulation in the liver) were more pronounced.
Utilizing spatial transcriptomics on the mouse liver samples, Joshi and his team analyzed genetic expressions for proteins produced in reaction to microplastics.
Genes coding for proteins PPAR-alpha (which regulates liver fat production) and Annexin A2 (associated with liver tissue repair) were highly active in livers affected by microplastics.
Larger studies are needed, but current findings suggest that both polyethylene microplastics and poor diet might be contributing to fatty liver disease development, particularly when combined.
Related: A Common Cholesterol Treatment May Also Remove PFAS And Microplastics From Blood
“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 remarks.
The research findings were published in Science Advances.
This article was fact-checked by Rachel Garner and edited by Clare Watson. While we pride ourselves on our process, we are only human. If you spot a mistake, please let us know.
