Coffee may protect against cirrhosis of the liver
Drinking coffee every day is linked to a reduced risk of liver cirrhosis, according to a new review of published evidence that also suggests drinking two extra cups a day may nearly halve the risk of dying from the disease.
The researchers say the link between coffee and lower risk of liver cirrhosis is larger than that between many medications and the diseases they prevent.
The systematic review and meta-analysis is published in the journal Alimentary Pharmacology & Therapeutics.
The researchers - from the University of Southampton in the UK - pooled and analyzed data from nine long-term studies covering nearly half a million men and women from six countries.
They found that increasing coffee consumption may substantially reduce the risk of liver cirrhosis.
The analysis shows a dose-response relationship between coffee consumption and liver cirrhosis - with more cups per day linked to lower risk.
Two extra cups of coffee per day were linked to a 44% lower risk of developing liver cirrhosis and a nearly 50% lower risk of death to the disease.
Liver cirrhosis can be fatal because it raises the risk of liver failure and cancer.
The condition develops when healthy tissue in the liver is replaced by scarred tissue, often as a result of long-term and persistent injury from viruses like hepatitis C and toxins like alcohol.
Liver cirrhosis is an important public health concern and a significant cause of disease and death in the US. The prevalence is likely to be higher than official figures suggest because many cases are undiagnosed.
A recent estimate suggests around 0.27% of Americans - some 633,323 adults - have liver cirrhosis, with 69% unaware of the fact they have the disease.
Effect is 'larger than that of statins on reducing cardiovascular risk'
In their paper, where they discuss the results, the authors explain that coffee has many biologically active ingredients, in addition to caffeine. These include "oxidative and anti-inflammatory agents, such as chlorogenic acid, kahweol and cafestol," and there is evidence, they note, that these may "confer protection against liver fibrosis."
In addition to a direct biochemical effect, there could also be an indirect effect of coffee protecting against cirrhosis, suggest the researchers. For example, they cite lab studies that show various compounds found in coffee block hepatitis B and C viruses and studies that show links between increased coffee consumption and reduction in type 2 diabetes.
The paper concludes that the analysis shows the link between increased daily coffee consumption and reduction in risk of liver cirrhosis is large - larger than that of many medications used for the prevention of disease.
"For example," note the authors, "statin therapy reduces the risk of cardiovascular disease by 25%."
They also point out that "unlike many medications, coffee is generally well tolerated and has an excellent safety profile."
Lead and corresponding author Dr. O. J. Kennedy, of Southampton's Faculty of Medicine, concludes:
"Coffee appeared to protect against cirrhosis. This could be an important finding for patients at risk of cirrhosis to help to improve their health outcomes. However, we now need robust clinical trials to investigate the wider benefits and harms of coffee so that doctors can make specific recommendations to patients."