There is a growing body of evidence that coffee may be good for your long-term health, reducing the risk of type II diabetes, Alzheimer's and Parkinson's. According to one recent meta-study, it may also lower your risk of liver damage from boozing. The study was conducted by scientists from the University of Southampton. It's not a clinical trial — rather, researchers pooled results from nine previous studies that recorded both the incidence of liver cirrhosis and caffeine consumption. In total, 432,133 participants contributed to the studies, across a broad demographic range.
Liver cirrhosis is a big killer, claiming over a million people worldwide every year. It's most famously caused by excessive long-term alcohol consumption, but also brought about by hepatitis infections, immune disorders and even obesity or diabetes.
The results of the meta-study demonstrate a significant protective effect from consuming coffee: the analysis shows that increasing coffee consumption by two cups per day halves the risk of liver cirrhosis, including alcoholic cirrhosis. The halving of the risk also holds true for death rates. The stats get better the more coffee you consume: four cups a day drops the risk of liver cirrhosis by 65 per cent.
Given the complex chemical makeup of coffee, it's difficult to say exactly how the caffeine is protecting the liver. This is also only a meta-study: although the analysis seems robust, controlling for bias and variables across that great a sample size and time period is an imperfect science at best.