LONDON: Drinking coffee every day may significantly reduce the risk of liver cancer and other serious liver diseases, according to a major long-term study published in the journal Clinical Gastroenterology and Hepatology.
The study, led by liver specialist Dr Hyunseok Kim of Cedars-Sinai Medical Center in Los Angeles, followed more than 354,000 participants for over a decade to examine the long-term relationship between coffee consumption and liver health.
Researchers found that people who drank five or more cups of coffee a day had a 32 percent lower risk of liver fibrosis, or scarring, a 47 percent lower risk of liver cancer, and a 42 percent lower risk of death from liver disease compared with those who consumed little or no coffee.
According to the study, the protective effect generally increased with the amount of coffee consumed.
People who drank one to two cups daily had a 20 percent lower risk of cirrhosis, a 24 percent lower risk of liver cancer and a 31 percent lower risk of liver-related death.
Those who consumed three to four cups a day had a 35 percent lower risk of both cirrhosis and liver cancer, along with a 41 percent lower chance of dying from liver disease.
Among participants drinking five or more cups daily, researchers recorded the greatest reduction in liver cancer risk at 47 percent.
Dr Kim described the research as “probably the most comprehensive long-term follow-up data” on coffee’s impact on liver health.
Benefits extend to decaffeinated coffee
Researchers found that the health benefits were not limited to caffeinated coffee.
According to Dr Kim, participants who regularly consumed decaffeinated coffee experienced similar protective effects, suggesting that caffeine itself is unlikely to be the primary reason for the improved liver outcomes.
“We do see that probably, the liver benefit from the coffee is not from the caffeine, because we do see the similar benefit in the decaffeinated drinkers,” Dr Kim said. He added that the benefits appeared to be more closely linked to coffee’s antioxidant properties.
The researchers said antioxidants naturally present in coffee may help reduce inflammation and fat accumulation in the liver by limiting the activation of biological pathways associated with scarring and chronic inflammation.
MRI scans support findings
The study’s conclusions were strengthened by advanced MRI scans and protein analyses carried out on a subset of participants.
According to the researchers, regular coffee drinkers showed healthier liver tissue, lower levels of liver fat and inflammation, and more favourable liver protein profiles.
Lauren Manaker, a registered dietitian nutritionist who was not involved in the study, said the combination of clinical outcomes, MRI imaging and protein analysis strengthened the findings.
“When the imaging and the proteins line up with the clinical outcomes, the overall picture becomes more believable than any one measure would be alone,” she said.
However, she stressed that the results showed an association rather than proving that coffee directly prevents liver disease.
Balanced approach
The researchers noted several limitations.
Coffee consumption was measured only at the beginning of the study and again more than 10 years later, leaving room for changes in participants’ drinking habits and other lifestyle factors during the intervening period.
Dr Kim also noted that more than 90 percent of participants were of European ancestry and generally health-conscious, while only about 10 percent underwent MRI scans.
He said further studies involving more ethnically diverse populations would be needed to confirm whether the findings apply more broadly.
The study also found that participants who added sugar or artificial sweeteners to their coffee experienced slightly smaller reductions in liver disease risk and showed higher markers of liver inflammation.
Researchers said maintaining a healthy lifestyle and following medical advice remain essential for preventing liver disease.
The researchers noted that previous studies have also associated regular coffee consumption with a lower risk of several chronic conditions, including type 2 diabetes, cardiovascular disease, stroke and dementia.
According to the study, cirrhosis affects more than 58 million people worldwide and causes nearly 1.5 million deaths each year.
Hepatocellular carcinoma, the most common form of liver cancer, accounts for approximately 685,000 new cases and more than 597,000 deaths globally every year.
