Moderate doses of coffee may be associated with healthier liver function

The work used data from more than 354,957 participants of the British Biobank (UK Biobank), who did not have cirrhosis or liver cancer at the start. Their health status was monitored for an average of 13 years, recording new cases of liver-related diseases and deaths. Several approaches were used to assess liver health: medical record analysis, liver MRI scans (to assess levels of fat, iron, fibrosis, and inflammation), and blood protein levels, including those that reflect scarring, inflammation, and normal liver function.

Compared to those who did not drink coffee, people who consumed five or more cups per day had:

• a 32% lower risk of developing cirrhosis;
• a 47% lower risk of liver cancer;
• there was a 42% lower risk of death from liver-related causes.

The protective effect was observed even with one or two cups per day, and it was most pronounced with three or four cups. Coffee drinkers also had lower levels of fat and iron in their livers, as well as less severe signs of fibrosis and inflammation based on MRI scans. Their blood tests showed higher levels of proteins associated with healthy liver function and lower levels of proteins indicating scarring and inflammation.

It is important that similar protective associations were found for caffeinated coffee and decaffeinated beverages. This suggests that caffeine itself is hardly the only active ingredient. Other natural compounds found in coffee are also likely to benefit.

Since the study was observational, it does not prove that coffee directly prevents liver disease, it is a statistical link. The authors insist that coffee should complement, rather than replace, generally accepted measures to prevent liver disease. For example, maintaining a healthy weight, limiting alcohol consumption, engaging in regular physical activity, and monitoring blood sugar, blood pressure, and cholesterol levels.

Additionally, experts do not recommend specifically increasing coffee consumption to five or more cups per day for the purpose of liver protection. Individuals with uncontrolled hypertension, irregular heart rhythms, severe anxiety, insomnia, or other conditions that require caffeine restriction should consult with a healthcare professional before making any changes to their habits.

The next step in the research is to identify the specific compounds in coffee responsible for the observed effects. As Dr. Shelley Lu, director of the Department of Gastroenterology and Hepatology at Cedars-Sinai, notes, the findings point to biological pathways associated with inflammation and scarring and highlight molecular points that can be further explored. This approach will help to better understand how coffee affects the liver and which groups of people may benefit the most from it.