Coffee curbs effects of liver disease: experts

Liver disease looms as a threat for an unprecedented number of Canadians, affecting an estimated three million people, many unaware they are sick.

But there is some surprising good news for those nursing damaged livers: a new review of 20 years of research, co-authored by Canadian and U.S. researchers, concludes that drinking coffee can significantly curb the seriousness of liver cirrhosis — and even lower the risk of contracting a deadly cancer.

The heated debate over whether coffee represents an overall health benefit or risk for the general population will undoubtedly continue.

But a Toronto specialist who helped conduct the review says he now recommends liver-disease sufferers drink two or three cups a day, more if they can tolerate it.

For those patients, the evidence is so convincing that the widely consumed beverage can be a useful therapy, perhaps even save lives, says Dr. Jordan Feld, a gastroenterologist at Toronto Western Hospital.

“We really have almost nothing else that helps,” he says.

“Besides taking away the primary cause of their liver disease — whether it’s stopping alcohol or, if it’s a viral infection, trying to treat or cure the infection — we don’t really have a lot of other things we can do to reduce the risk.”

While people with kidney failure can go on dialysis, those with end-stage liver disease have little alternative but to wait for a transplant. About 5,000 die every year in this country.

The Canadian Liver Foundation has called the growing prevalence of the condition a crisis, complaining it gets too little attention because of the association with drinking, though hundreds of thousands have liver disease triggered by viruses. About 20 per cent of the Canadians with chronic hepatitis C don’t even know they have it.

Feld, a University of Toronto professor, said he first began exploring the coffee effect several years ago while working at the U.S. National Institutes of Health, skeptical at first, but increasingly persuaded.

In a paper just published in the journal F1000 Research, he and three American colleagues summarized numerous studies conducted since the early 1990s.

The research was mostly observational — not typically as reliable as controlled trials where patients would be randomly assigned to drink coffee, or not — but it was highly consistent, they concluded.

Drinking coffee appears to reduce the risk of cirrhosis (the scarring that hinders the proper functioning of the liver) and hepatocellular carcinoma, a cancer that can develop in a badly scarred organ.

One 2009 study found that half as many liver-disease patients who drank three or more cups of coffee a day developed the cancer as those who drank none.

The same kind of association does not seem to come with drinking tea, decaffeinated coffee or caffeinated soft drinks, the research indicates. Some evidence suggests filtered coffee is more effective than espresso.

Feld and his colleagues theorize that caffeine is the key ingredient, possibly because of its effects on adenosine receptors, which are involved in liver scarring.

The “exciting” science around coffee could help understand how cirrhosis occurs, and even lead to new drug treatments, they argue.

Dr. Eric Yoshida, head of gastroenterology at Vancouver General Hospital, is not quite as definitive in recommending coffee for liver patients, but agrees the evidence is fairly clear that it can help.

“I think it’s pretty hard to say ‘everybody should drink coffee,’ “he says.

“(But) coffee drinking, at least for your liver, is maybe a beneficial thing and at least it’s not detrimental.”