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Study: Broccoli sprouts may prevent stomach cancer

(Xinhua)
Updated: 2009-04-07 14:29

WASHINGTON -- A small, pilot study in 50 people in Japan suggests that eating two and a half ounces of broccoli sprouts daily for two months may confer some protection against a rampant stomach bug that causes gastritis, ulcers and even stomach cancer.

The paper of the study was published Monday in US journal Cancer Prevention Research.

The study builds on earlier test-tube and mouse studies at Johns Hopkins University and elsewhere about the potential value of sulforaphane, a naturally occurring biochemical found in relative abundance in fresh broccoli sprouts.

Sulforaphane appears to trigger cells in the body, including in the gastrointestinal tract, to produce enzymes that protect against oxygen radicals, DNA-damaging chemicals, and inflammation.

Working in Japan where there is high incidence of chronic bacterium Helicobacter pylori (H. pylori)-infection, an international research team including Johns Hopkins University scientists gave 25 H. pylori-infected subjects two and a half ounces (about 71 grams) per day of broccoli sprouts for two months.

Another 25 infected people consumed an equivalent amount of alfalfa sprouts which, although rich in phytochemicals, don't contain sulforaphane.

The researchers assessed the severity of Helicobacter infection at the start of the study, after four and eight weeks of treatment, and again eight weeks after intervention was stopped.

They found that eating a daily dose of broccoli sprouts reduced by more than 40 percent the level of HpSA, a highly specific measure of the presence of components of H. pylori shed into the stool of infected people.

There was no HpSA level change in control subjects who ate alfalfa sprouts. The HpSA levels returned to pretreatment levels eight weeks after people stopped eating the broccoli sprouts, suggesting that although they reduce H. pylori colonization, they do not eradicate it.

"We know that a dose of a couple ounces a day of broccoli sprouts is enough to elevate the body's protective enzymes," says Jed W. Fahey, an author of the paper who is a nutritional biochemist in the Johns Hopkins University School of Medicine.

"That is the mechanism by which we think a lot of the chemoprotective effects are occurring. What we don't know is whether it's going to prevent people from getting stomach cancer. But the fact that the levels of infection and inflammation were reduced suggests the likelihood of getting gastritis and ulcers and cancer is probably reduced," he said.

Citing their new "demonstration of principle" study, the international team of scientists caution that eating sprouts containing sulforaphane did not cure infection by H. pylori. They do not suggest that eating this or any amount of broccoli sprouts will protect anyone from stomach cancer or cure GI diseases.

"The highlight of the study is that we identified a food that, if eaten regularly, might potentially have an effect on the cause of a lot of gastric problems and perhaps even ultimately help prevent stomach cancer," says Fahey.

The discovery that sulforaphane is a potent antibiotic against H. pylori was reported in 2002 by Fahey and colleagues at Johns Hopkins. "Broccoli sprouts have a much higher concentration of sulforaphane than mature heads," Fahey explains, adding that further investigation is needed to affirm the results of this clinical trial and move the research forward.

Classified a carcinogen by the World Health Organization, H. pylori is a gastrointestinal tract germ that manages to thrive in the lining of the stomach despite the strength of natural acids there that rival that of car batteries.

Afflicting several billion people -- roughly half of the world's population -- this corkscrew-shaped bacterium has long been associated with stomach ulcers, which now are frequently cured by antibiotics.