Coffee, Tomatoes, and Microplastics: Three Recent Findings on Liver Health

Good news for coffee lovers: a large study published in Clinical Gastroenterology and Hepatology last July found that daily coffee consumption is associated with a much lower risk of cirrhosis and liver cancer. The findings reinforce growing evidence that an everyday beverage can have a significant impact on an organ that has long received little attention: the liver.

The study analyzed data from more than 355,000 adults in the U.K. Biobank over an average of 13 years. All participants were free of cirrhosis and liver cancer at the start of the study. As a result, those who consumed five cups of coffee or more per day had a 32% lower risk of cirrhosis and an almost 50% lower risk of liver cancer compared with those who did not drink coffee.

Hyunseok Kim, a transplant hepatologist at Cedars-Sinai Medical Center in California and one of the study's authors, stressed that the dose-response relationship was clear. “The more coffee intake, the lower the risk of cirrhosis, liver cancer, and liver-related death,” he said, as quoted by Medical News Today. Nevertheless, he cautioned that observational studies do not prove causation, but rather show a consistent, strong association.

Meanwhile, for people with metabolic dysfunction-associated steatotic liver disease (MASLD) — a fatty liver condition linked to metabolic syndrome — regular tomato consumption may offer some relief. A study published in the journal Nutrients in July involved 79 adults with MASLD. The control group followed a tomato-free diet, while the other group consumed 200 grams of raw tomatoes and 50 grams of tomato sauce every day for six weeks.

Both groups did experience a reduction in liver fat, but the group that consumed tomatoes showed the greatest reduction. However, Randa Abdelmasih, an endocrinology and obesity specialist at the University of Texas Medical Branch who was not involved in the study, offered an important caveat. “This study shows improvement in liver fat, but there was no significant improvement in liver stiffness, fibrosis scores, liver enzymes, insulin resistance, inflammatory markers, lipid profile, or body composition,” she said. “So, while the imaging findings are interesting, we cannot yet conclude that tomato consumption meaningfully changes disease progression or improves clinical outcomes.”

On the other hand, concern arises from microplastic exposure. A study in mice published in Science Advances in June found that polyethylene — a major source of microplastics — can increase the risk of liver damage or worsen existing liver conditions. Researchers tested the effects of polyethylene in mice fed either a control diet or a diet designed to induce metabolic dysfunction-associated steatohepatitis (MASH), a more severe form of liver disease.

As a result, polyethylene exposure caused liver problems in both groups and worsened liver injury in mice on the MASH diet. Opel Baker, a general practitioner at Mayfield Clinic who was not involved in the study, commented, “These findings suggest that polyethylene microplastics can affect liver metabolism and potentially contribute to fatty liver changes in mice, but we cannot assume the same effects occur in humans.” He added that human studies are still greatly needed before concluding that microplastics cause fatty liver disease.

These three findings offer diverse perspectives: from the potential benefits of coffee and tomatoes to the risks that may arise from everyday plastic exposure. For Indonesia, where the prevalence of fatty liver disease continues to rise alongside surging obesity and diabetes, education about diet and reducing microplastic exposure is becoming increasingly relevant. The question is, how ready is our health system to integrate these findings into lifestyle guidelines? And will food packaging regulations adapt to the evolving evidence?