Drinking more coffee may be a simple, safe and accessible public health intervention to prevent liver disease and reduce liver-related mortality, according to Victorian hepatologists.
An increasing body of evidence shows an association between coffee intake and liver health, says Dr Paul Gow of the Victorian Liver Transplant Unit, The Austin Hospital, Melbourne.
Writing in Alimentary Pharmacology and Therapeutics, Dr Gow and colleagues at the Department of Gastroenterology, St Vincent’s Hospital, say a growing number of publications are reporting that coffee intake not only improves liver biochemistry but also slows progression to cirrhosis and is associated with a reduced risk of death from liver disease.
The protective benefit of coffee is believed to be related to an attenuating effect on liver fibrogenesis and liver damage, unrelated to caffeine. The exact mechanism remains unclear but might involve compounds in coffee such as diterpenes and chlorogenic acids, with increased consumption shown to improve insulin sensitivity, and lower rates of biochemical inflammation via pro-inflammatory cytokines.
To further investigate the potential benefit of coffee against liver disease, Dr Gow and colleagues modelled the likely impact of increased per capita coffee consumption on the 1.2 million adult liver-related deaths recorded in 2016.
They used published risk ratios for >2 cups coffee/day (RR 0.54, 95% CI 0.42-0.69) and ≥4 cups/day (RR 0.29, 95% CI 0.17-0.50), adjusted for confounders.
The modelling showed that if all countries with per capita coffee intake ≤2 cups/day increased to >2 cups/day the predicted total number of liver-related deaths would have been reduced to 630,947 in 2016, with 452 861 deaths averted. This represented a population preventable rate (PPR) of 7.8 liver-related deaths/100 000/year compared to the median global liver mortality rate in 2016 of 15 deaths/ 100 000 population/year.
The predicted number of liver-related deaths averted would be even greater with four cups of coffee a day, with estimates of 360 523 deaths (723 287 avoided, PPR 12.1 deaths/100 000/year).
The study authors said the benefits would likely be greatest in regions outside of Europe that currently have low levels of coffee consumption.
They cautioned that the protective benefits of coffee were based on observational studies and would need to be confirmed in prospective trials. Nevertheless, they noted the strength of evidence has been considered compelling enough for the European Association for the Study of the Liver (EASL) Clinical Practice Guidelines for both hepatocellular carcinoma and NAFLD to recommend increased coffee consumption in people with chronic liver disease to reduce liver disease progression, HCC incidence and liver-related mortality.
“If the impact of coffee on liver-related mortality shown in cohort studies is confirmed in clinical trials, increasing per capita coffee consumption to more than two cups per capita per day on a population level has the potential to avert hundreds of thousands of deaths from liver disease annually,” they concluded.