Better source than red wine, green tea or soy products
Researchers have discovered a potent antioxidant in beer that gives new meaning to the traditional toast: "to your health." The finding is reported in the September issue of the Journal of Agricultural and Food Chemistry, a peer-reviewed journal of the American Chemical Society, the world's largest scientific society.
Hops, used in most beers to provide flavoring, contain substances known as prenylated flavonoids. They are a better source of antioxidants than red wine, green tea and soy products, according to Donald Buhler, Ph.D., lead author of the study from Oregon State University. (Antioxidants - substances that protect against the damaging effects of oxygen and nitrogen in the human body - help prevent high cholesterol, heart disease, cancer and Alzheimer's disease.)
But to maximize the health benefits of hops, you'd have to drink some 450 liters of beer per day, according to Buhler. The most likely outcome for the research, therefore, is a pill that captures their enhanced antioxidant activity, he said.
"I tell people they can't cure their disease by drinking beer - and it might just help," Buhler said. "The bottom line is that you're going to get some, but not preventative, levels of antioxidants by drinking beer."
Different beers have varying levels of antioxidants, ranging from a high of four milligrams per liter for some lager beers to negligible levels in some microbrews.
Previous research indicates that beer has cancer-fighting characteristics and antioxidant properties. The current research identifies the heretofore-unknown reason for these healthful qualities and suggests, for the first time, their source: the prenylated flavonoids in hops - specifically, the compound xanthohumol, Buhler said.
Xanthohumol (zan-tho-HUGH-mol), found exclusively in hops, is six times more effective than antioxidants found in citrus fruits and almost four times more effective than antioxidants found in soy products, Buhler said. Combined with vitamin E, xanthohumol has even greater antioxidant activity, he noted.
The compound's chemical structure could explain its added potency, Buhler said. As a prenylated flavonoid, xanthohumol has an additional layer of protection that allows it to survive longer in the body than other known flavonoids. A prenyl group has a particular arrangement of carbon and hydrogen molecules that have protective properties.
Flavonoids have been known to be antioxidants for years. Because they are a natural product, the U.S. Food and Drug Administration does not regulate them. Flavonoids are widely sold in pill form in health food stores and supermarkets, where they are presented as nutritional supplements.
"All we're saying is that the compounds we tested have better antioxidant activity than previously known flavonoids," Buhler said. "It takes less of these to do the same job as others and they do a better job with the same amount."
The research was funded by the Linus Pauling Institute at Oregon State University, the Hop Research Council and a grant from the National Institute of Environmental Health Sciences.
The online version of the research paper cited above was initially published July 21 on the journal's Web site. Journalists can arrange access to this site by sending an email to newsroom@acs.org or calling the contact person for this release.
Donald Buhler, Ph.D., is a professor in the department of environmental and molecular toxicology at Oregon State University.
A nonprofit organization with a membership of 161,000 chemists and chemical engineers, the American Chemical Society publishes scientific journals and databases, convenes major research conferences, and provides educational, science policy and career programs in chemistry. Its main offices are in Washington, D.C., and Columbus, Ohio.
Journal
Journal of Agricultural and Food Chemistry