Go find this article. Granted, it's written by the president of Illy... but he is a biochemist. One of the statistics in there is that there have been over 100 studies on the effects of coffee and none of them have found anything negative. nvm, here you go: http://poplab.stanford.edu/pdfs/Illy-ComplexityCoffee-sciam02.pdfCoffee and caffeine have been the subject of extensive scientific study during the past quarter of a century, with 1,500 TO 2,000 PAPERS PUBLISHED EVERY YEAR on the topic. Despite this close scrutiny, few negative health effects have been definitively linked to the moderate consumption (TWO CUPS A DAY) of caffeinated coffee. In fact, recent work indicates that roasted coffee can be a good source of antioxidants.
Hang on, I'm not saying that I think it is harmful, just that I wouldn't be surprised if it were eventually found to be harmful. Thanks for the link anyway. Edit - A great line from that link:Sniffing roasted coffee aromas that have been fractionated by a gas chromatograph is an enlightening experience: one may recognize the aroma of roses, Darjeeling tea, chocolate, vanilla and violets, as well as truffles, soup, cheese, sweat and even what is called cat scent which, if diluted, smells like sauvignon blanc wine but in a concentrated sample is disgusting.