Cafestol and kahweol, compounds that are extracted from the beans' oil during brewing. Unfiltered coffee, such as French press or boiled coffee, contains these compounds.
In excess, coffee, and more particularly, caffeine, can cause problems. But the
fretting about two or three cups a day, or even more, is fading as study results
suggestive of health benefits from coffee keep on coming in. In 2011,
researchers reported findings that coffee drinking is associated with a lower
risk of depression among women, a lower risk of lethal prostate cancer among
men, and a lower risk of stroke among men and women. Go back a little further,
and you'll come across reports of possible (it's not a done deal)
protective effects against everything from Parkinson's disease to diabetes to
some types of cancer.
http://www.health.harvard.edu/newsletters/Harvard_Health_Letter/2012/January/what-is-it-about-coffee
More info regarding diet.
http://www.trcc.org/community/