I've read several places (for instance, in a book by the doctors Eades) that coffee is tough on your liver. But, I can't for the life of me remember if it's the coffee or the caffeine. And now, a quick Googling turns up some hits about coffee protecting against liver cancer.
So, anyone know what the deal is with coffee and stress on the liver? (For what it's worth, I'd be much happier to give up caffeine and switch to decaf than give up my morning coffee altogether.)
I also wrote a post on coffee which contains some references regarding it's benefit in non-alcoholic fatty liver disease and oxidative stress in the liver.
I tried a very brief more recent search in pubmed just now and didn't really come across anything indicating in is bad for the liver. Only thing I came across was that it seems to protect against liver cancer and liver disease ( http://www.ncbi.nlm.nih.gov/pubmed/23465359 ), and this study that shows it protects against the negative impacts of excessive alcohol intake: http://www.ncbi.nlm.nih.gov/pubmed/23492307. So all seems still in line with the article I wrote previously.
The more I read about it, the less I think that coffee is anything but healthful for the vast majority of people.
There are compounds such as caffeine, caffeic acid, and various aromatics from burning the coffee seed that make the liver work hard to break down. It is still not nearly as hard on the liver as fried foods for example. My liver is nothing to write home about, but it will take unlimited amounts without complaints. But for me even a single espresso early in the morning will give me a bad night the night after.
Coffee can decrease enzymes in the liver, which I guess might make it harder to do its job. Overall coffee actually protects the liver and reduces the risk of liver cancer! Yay Coffee!
Coffee is a mixed bag. It has good and bad effects. There are many different compounds in coffee. It is a legume so for starters it has phytic acid which will bind with and carry away minerals from the food you eat with it. If you do switch to decaff, get the water process decaff, (which is more expensive and harder to find). The decaff in the grocery stores is processed using all kinds of denaturing chemicals which are probably worse for you than the caffeine.