Broccoli Sprouts Fight Ulcers and Cancer

Broccoli Sprouts Fight Ulcers and Cancer

By Rick Weiss

Bad news for those who can't stomach broccoli: New research suggests that broccoli is especially good for the stomach.

A compound found in broccoli and broccoli sprouts appears to be more effective than modern antibiotics against the bacteria that cause peptic ulcers. Moreover, tests in mice suggest the compound offers formidable protection against stomach cancer -- the second most common form of cancer worldwide.

If upcoming human tests confirm the findings, a daily snack of tangy broccoli sprouts could become a medically indicated staple -- especially in Asia, where the ulcer bacteria and stomach cancer occur in epidemic proportions.

The new work, led by scientists at Johns Hopkins University, is the latest in a 10-year series of studies on the cancer-fighting potential of broccoli.

It started in 1992, when Hopkins pharmacology professor Paul Talalay and his colleagues showed that sulforaphane -- a substance produced in the body from a compound in broccoli -- could trigger the production of phase II enzymes. The enzymes can detoxify cancer-causing chemicals and are among the most potent anti-cancer compounds known.

Scientists had known for years that cancer is less common in people who eat more vegetables, but the broccoli studies were among the first to point to a particular chemical that might account for much of that protection.

Subsequent studies found that sulforaphane could prevent the development of breast and colon cancer, as well as other tumors, in mice. Then Talalay's team found that the key protective compound in broccoli (a chemical called glucoraphanin, which the body turns into sulforaphane) is at least 20 times more concentrated in three-day-old broccoli sprouts than it is in broccoli.

A single ounce of sprouts has as much glucoraphanin as a pound and a quarter of cooked broccoli, offering a simpler -- and less flatulent -- means of consuming potentially healthful quantities of the protective agent.

Talalay and co-worker Jed W. Fahey founded a company to make the sprouts for grocery stores. So it was as economic stakeholders (limited under Johns Hopkins's conflict-of-interest rules) that they and their collaborators began testing the effects of sulforaphane on the bacterium Helicobacter pylori. The microbe, found globally but especially in Asia, causes ulcers and increases a person's risk of getting gastric cancer threefold to sixfold.

Fahey said the study arose after he learned that two employees at a broccoli sprout facility with longstanding ulcers had apparently been cured after they took up snacking on the sprouts.

Working with researchers from the National Scientific Research Center in Nancy, France, the team found that sulforaphane easily kills H. pylori, a microbe that is notoriously difficult to eradicate even with combinations of two or three antibiotics. In test tube studies, it even killed H. pylori that had burrowed inside human stomach lining cells, as the microbe often does to escape attack.

In separate studies involving mice that were dosed with a chemical known to cause stomach cancer, mice pre-treated with sulforaphane had 39 percent fewer tumors.

The findings, published in today's online edition of Proceedings of the National Academy of Sciences, doesn't mean broccoli can cure ulcers or prevent stomach cancer in people.

"One question is, would you have to eat a ton of broccoli a day to get enough of this to be effective?" said Frank Gonzalez, a scientist at the National Cancer Institute.

But Fahey said he is optimistic. "The levels that are effective [in test tubes] are levels that could be achieved by eating a serving or so of broccoli sprouts, based on the chemistry we know," Fahey said. "This isn't one of those rat studies in which you need 400 times the maximum amount a human could handle."

Talalay said the group is preparing to start a clinical trial in Japan to test the sprouts' effectiveness in people infected with H. pylori. About 80 percent of Japanese adults harbor the microbe in their stomachs -- one reason that gastric cancer is the No. 1 cancer killer in Japanese women and No. 2 after lung cancer in Japanese men.

The microbe is similarly common and deadly in many parts of the world where antibiotics are unavailable or unaffordable, Talalay said.

"Gratifyingly, this is a dietary approach," he said, "which is the only approach feasible or practical if you want to knock down the incidence of this very serious disease in the parts of the world where it is most prevalent."