Scientists from Johns Hopkins University in Baltimore and the French National Scientific Research Center have completed a laboratory study that shows that sulforaphane, a compound found in abundance in broccoli and broccoli sprouts, also kills helicobacter pylori, the bacterium responsible for a majority of stomach ulcers and stomach cancers worldwide.
"The results are quite interesting, but the dosage and human studies are still needed," says Shiuan Chen, professor of biological sciences at City of Hope Cancer Center in Los Angeles.Clinical trials to see whether dietary intake of vegetables containing sulforaphane yields the same results are slated to begin shortly.
The findings, reported in today's issue of the Proceedings of the National Academy of Sciences, could have significant public health implications. About 40 percent of people in developed countries and 70 percent in developing nations carry heliobacter. Infected individuals have a three-to-six times higher risk for developing stomach cancer, the second most common cancer in the world and the leading cancer killer in the developing regions of Asia, Africa and South America.
Stomach cancer is much less common in areas of the world where there is a high consumption of fruits and vegetables, indicating that the cancer is highly preventable.
In areas of the world where H. pylori is most common, antibiotics are difficult to obtain and use and are not always effective. Some 15 percent to 20 percent of infections are resistant to conventional antibiotics.
The new research started in an most unscientific way, when Dr. Jed Fahey of Johns Hopkins, the lead author of the study, heard a story about several individuals who'd had stomach ulcers and who had unexpectedly seen their symptoms disappear after eating three-day-old broccoli sprouts.
Broccoli and broccoli sprouts are known to contain abundant quantities of sulforaphane, a compound that has been shown to inhibit the growth of a variety of microorganisms. Sulforaphane also can protect cells against cancer by increasing production of certain enzymes.
Fahey and his colleagues took sulforaphane to the laboratory and found that it killed many different strains of heliobacter, including strains that were resistant to commonly used antibiotics. And unlike antibiotics, sulforapahen killed the bacterium whether it was inside or outside the cells.
Bacteria that "hide" in cells lining the stomach are difficult to eradicate and have posed a major problem in combating the disease.
"It [broccoli] hits resistant bacteria and it's also intracellular," says Dr. Paul Talalay, a co-author of the study and professor of pharmacology at Johns Hopkins University School of Medicine. "It's better than conventional antibiotics."
The researchers also showed that sulforaphane can protect against stomach cancer in mice.
Though these preliminary results are hopeful, it remains to be seen whether dietary sources of sulforaphane will have the same or similar effects in humans.
There's also the question of whether this "treatment" could be exported to developing regions of the world.
"The implementation of any type of therapy on large populations that are developing is an incredibly complex problem, but it would be much easier to implement by a dietary strategy than by having take pills every day," Talalay says.
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