High coffee consumption was linked to a lower risk for elevated liver stiffness, though no such association was seen with steatosis, researchers found in a cross-sectional study.
In a dietary analysis involving over 4,500 adults, drinking more than 3 cups of coffee (versus none) was associated with a 0.9 kPa reduction (95% CI -1.6 to -0.1, P=0.03) and with a reduced odds of liver stiffness (≥9.5 kPa; OR 0.4, 95% CI 0.2-1.0, P=0.05), reported Elliot Tapper, MD, of the University of Michigan in Ann Arbor, and colleagues.
However, no association was found between coffee and controlled attenuation parameter (CAP), a measure of liver fat, the authors wrote in Clinical Gastroenterology and Hepatology.
“The best theory we have is that caffeine reduces fibrosis,” Tapper told MedPage Today. “The association with liver health goes up with the more cups you drink.”
Prior research has suggested a lower risk for cirrhosis and advanced liver disease with coffee consumption, but many of the studies supporting this notion have various biases, the authors explained.
“A leading hypothesis was that coffee would reduce fat in the liver, although that was not shown to be the case in this study,” Andrew Talal, MD, of the University at Buffalo in New York, told MedPage Today. “Similarly, it appears as though the protective effect of coffee is independent of the quantity of caffeine contained within the coffee, which is consistent with the findings of another large study from the U.K.”
“These studies support the consumption of at least moderate amounts of coffee for its protective effects against liver scarring and the development or progression of chronic liver disease,” added Talal, who was not involved in this study, said.
For their study, Tapper and colleagues assessed 4,510 nationally representative participants (mean age 48) from the National Health and Nutrition Examination Survey (NHANES). People age 20 and older who underwent two 24-hour dietary recall exams and underwent transient elastography were included. Hepatitis patients were excluded.
The main outcome evaluated the quantity of coffee consumed and its association with liver stiffness measurements (LSM), with a ≥9.5 kPa considered a threshold for advanced fibrosis. Controls included those who reported tea and decaffeinated coffee consumption.
About three-fourths of the participants were overweight or obese and about half engaged in physical activity. Comorbidities included diabetes (11%) and chronic liver disease (5%). About 63% were white and 23% consumed a minimum of two daily alcoholic drinks. Most individuals (n=3,797) had LSM values below 7.0 kPa, while 415 had values ranging from 7 to 9.5 kPa, and 298 had values of 9.5 kPa or above.
Adjusting for the consumption of sugar-sweetened beverages and Healthy Eating Index-2015 scores, coffee consumption was still associated with a reduction of LSM (OR 0.4, 95% CI 0.1-0.9, P=0.03).
The analysis had several limitations, the researchers acknowledged, including the potential for unmeasured confounding, recall bias, and the limited dietary data.
The study was supported by the NIH.
Tapper disclosed relationships with Allergan, Novartis, Valeant, Novo Nordisk, Gilead, Axcella, Mallinckrodt, Kaleido, and Bausch Health.