Drinking more than three cups of coffee per day was linked to a reduction in liver stiffness (an indicator of liver fibrosis) but not liver fat accumulation, according to results published in Clinical Gastroenterology and Hepatology. What’s more, these findings applied to both caffeinated and decaffeinated coffee.
Previous research has shown that drinking coffee is associated with a lower risk of chronic liver disease and fatty liver disease, better liver health for people with hepatitis C and a reduction in liver-related death. Non-alcoholic fatty liver disease (NAFLD) is a growing cause of liver problems in the United States and worldwide. Over time, NAFLD, chronic hepatitis B or hepatitis C, heavy alcohol use and other causes can lead to the build-up of scar tissue (fibrosis), advaced scarring (cirrhosis) and even liver cancer.
In the present study, Elliot B. Tapper, MD, of the University of Michigan at Ann Arbor, and colleagues set out to explore the effect of coffee consumption on liver fibrosis and steatosis (fat accumulation) in a representative population.
The researchers used data from the National Health and Nutrition Examination Survey (2017-2018) on 4,510 participants over age 20 who had undergone liver imaging using FibroScan (transient elastography) and two 24-hour dietary recall interviews, which assessed details about all foods and beverages consumed within the prior day. The average age was 48 years, 73% had overweight or obesity and 11% had diabetes. Nearly half (48%) engaged in intense physical activity, and 23% drank at least two alcoholic drinks per day. People with hepatitis were excluded.
The researchers looked at the links between coffee drinking and two indicators of liver health: a liver stiffness measurement greater than 9.5 kilopascal (kPa), meaning advanced fibrosis, and an elevated controlled attenuation parameter (CAP) score, a measure of the intensity of sound waves as they travel through fatty liver tissue. Liver stiffness and CAP scores were compared for people who drank caffeinated coffee, decaffeinated coffee or tea.
The team found no link between coffee consumption and the CAP score or presence of liver fat. But people who drank more than three cups of coffee per day had lower liver stiffness measurements than those who drank no coffee (0.9 kPa lower). They were also less likely to have a liver stiffness measurement greater than 9.5 kPa. The protective effect was seen in people who drank either caffeinated or decaffeinated coffee—but not tea—and remained after adjusting for diet and consumption of sugar-sweetened beverages.
“Coffee is associated with lower liver stiffness but not steatosis as measured by CAP among U.S. adults,” the researchers wrote. “The protective nature of coffee consumption is…not attributable to caffeine and persists in participants regardless of their diet quality.”