From the March 2006 issue of All About Beer:
The newest report on the health benefits of beer focuses on hops. Scientists at Oregon State University's Linus Pauling Institute discovered the cancer-related properties of xanthohumol--a flavonoid compound--about 10 years ago. Xanthohumol is one of a number of compounds for cancer chemoprevention studied at OSU. The more highly hopped a beer, the greater the level of xanthohumol. Studies of the compound have been conducted for its benefits related to breast enlargement in women and prevention or treatment of post-menopausal "hot flashes" and osteoporosis, as well as the prevention of cancer.
All About Beer: Celebrating the World of Beer Culture