Sauerkraut a health food? Not yet. But midwestern scientists have found evidence that something in this pickled cabbage and related foods blocks the action of estrogen, a hormone that can fuel the growth of breast cancer and other reproductive-tract malignancies.
Nutritionist William G. Helferich of the University of Illinois at Urbana-Champaign and his colleagues were trying to tease out why Polish women who have moved to the United States are far more likely to develop breast cancer than their kin remaining in the Old Country are.
One distinguishing factor turned out to be consumption of cabbage. European Poles eat far more.
Cabbage belongs to the Brassica family. A host of recent studies has shown that brassicas—which include broccoli, cauliflower, brussels sprouts, and mustard—possess cancer-fighting compounds. Helferich wondered whether fermenting such veggies, as in making sauerkraut, would create new anticancer agents. Others might arise when stomach juices acidify vegetable compounds. Specifically, the researchers wondered whether the brassicas give rise to estrogen blockers.
To investigate, the researchers stimulated test-tube colonies of human breast-cancer cells with estrogen, then added extracts of plain cabbage, sauerkraut, or acidified brussels sprouts.
Low-concentration extracts of the samples—typically 5 to 25 parts per billion—not only slowed the growth of estrogen-fed cells but also blocked estrogen’s ability to turn on a particular gene. The scientists found little difference in the three vegetable preparations’ potencies.
At parts-per-million concentrations, however, each extract mimicked estrogen—spurring cell growth and gene activity, the researchers found.
“Though it’s very unlikely you’d get those higher concentrations in the blood from eating brassicas,” Helferich says, he suspects that “it is realistic you could get the antiestrogenic doses.” His group’s findings, which will appear in the October Journal of Agricultural and Food Chemistry, are currently available on the Internet.
The Illinois scientists have partially purified antiestrogenic constituents of the extracts and distributed portions to other researchers who study brassicas’ cancer-fighting compounds. It appears these newly isolated antiestrogenic agents “are novel,” Helferich told Science News.
The study wins high marks for its methodology from endocrinologist Ana Soto of the Tufts University School of Medicine in Boston. Although she finds the brassicas’ dose-dependent activities interesting, both she and Paul Talalay of the Johns Hopkins School of Medicine in Baltimore point out that until the active agents are purified and individually tested in animals, it will be impossible to gauge whether these compounds might persist in people. Such experiments will be critical for estimating the cancer-fighting prospects of the vegetables.
Scientists had thought that any anticancer benefits from brassicas traced to sulforaphane (SN: 9/20/97, p. 183: http://www.sciencenews.org/sn_arc97/9_20_97/fob3.htm) and indole-3 carbinol (SN: 3/6/99, p. 157). The findings by Helferich’s team suggest these foods might offer even more “potentially important” agents and point toward a new class of drugs to reduce cancer risk, observes Barnett Zumoff, chief of endocrinology at Beth Israel Medical Center in New York.