For decades it seemed researchers were bent on demonizing our beloved morning wake-up elixir, coffee. But the tide turned and these days barely a month goes by without a new study touting the health benefits of the invigorating infusion.
The latest of these studies finds that regular coffee consumption, whether caffeinated, decaffeinated or instant, appears to protect our livers from some really scary diseases, including cancer.
Using information from a database of nearly 500,000 adults based in the U.K., researchers determined that coffee drinkers had a 21% reduction in the risk for chronic liver disease overall, a 20% reduction in the risk of fatty liver disease and a 49% reduction in the risk of death from chronic liver disease, according to the report published in BMC Public Health.
“Chronic liver disease is a huge problem for global health, especially low income countries where treatments are less available,” said the study’s lead author, Oliver Kennedy, a visiting research fellow at the University of Southampton in the U.K.
“Our finding that drinking coffee might protect against chronic liver disease is significant because coffee is cheap, widely available, safe and well tolerated by most people,” Kennedy said in an email. “It’s also reassuring that all coffee types seem to be protective, including decaffeinated coffee, which might be preferable for certain people, for example, pregnant women.”
It’s not yet known how coffee might protect the liver, Kennedy said. “Coffee contains many hundreds of compounds and we don’t know exactly which of these confers the protective effect,” he added. “It may be one compound or a combination. The fact that different types of coffee, which contain different chemical compounds, seem protective suggests it might be a combination.”
Does the effect increase as the number of cups goes up?
“It was difficult to assess the effects of very high levels of coffee consumption as the numbers of people drinking these amounts in our study were relatively small,” Kennedy said. “From the data available, there did seem to be a dose-response with larger amounts conferring more protection.”
“However,” Kennedy said, “there is likely a level beyond which increasing coffee consumption confers no further benefit. For example, in our study the benefit of five or more cups each day was generally smaller than for three or four cups each day, though still protective compared to no coffee.”
To explore whether coffee might help protect the liver, Kennedy and his colleagues turned to the U.K. Biobank, a prospective longitudinal study that is designed to look at the genetic and behavioral determinants of health outcomes.
Their analysis was based on information from 494,585 Biobank participants who had provided information on coffee consumption and who did not have chronic liver disease when they joined. Among the study participants, 384,818 (78%) consumed ground or instant caffeinated or decaffeinated coffee, while 109,767 (22%) did not drink any type of coffee.
During the median of 10.7 years of follow-up there were 5,439 new cases of chronic liver disease or fatty liver disease, 184 new cases of liver cancer, 74 deaths from cancer and 301 deaths from chronic liver disease.
While other studies have suggested that coffee might help protect the liver, “this is probably the largest one with the best long-term follow-up, to reveal the protective effects of coffee on liver disease of all types,” said Dr. Scott Friedman, dean for therapeutic discovery and chief of the division of liver disease at the Icahn School of Medicine at Mount Sinai in New York.
“What’s exciting about this is it not only decreases liver disease, but also cancer,” Friedman said. “Another interesting thing is that they showed that it did not matter whether the coffee was caffeinated, decaffeinated or instant. We actually encourage patients to drink a little coffee. And now, for those who are worried about being kept awake, there is reassuring data to show decaf is also protective.”
While the maximum benefit was observed in the group who drank ground coffee, instant coffee drinkers also saw a benefit, albeit a smaller one.
Overall this is very good news considering the high numbers of Americans who have liver disease, particularly non-alcoholic fatty liver disease, Friedman said. “Most don’t know they have it,” he added. “Best estimates are that the prevalence of non-alcoholic fatty liver disease is 32% in the U.S. and at least 25% of these have NASH (non-alcoholic steatohepatitis, the more severe form). That means approximately 102,400,000 have non-alcoholic fatty liver disease, and about 25 million have NASH.”
As fatty liver disease progresses, scarring starts to develop, Friedman said, adding that the condition leaves patients at a heightened risk for liver cancer. Non-alcoholic fatty liver disease is also a common indication for liver transplants, he added.
Currently there is no medication to treat the disease, so anything, such as coffee, that might be able to protect the liver is welcome, Friedman said. “It’s been a major focus of drug development,” he added. “There are almost 75 drugs in clinical trials.”