By David Gutierrez
Eating just a few ounces of broccoli each day may significantly reduce a person’s risk of ulcers and stomach cancer, researchers from Johns Hopkins University have found.
In a study published in the journal Cancer Prevention Research, scientists assigned 50 people in Japan to eat either 2.5 ounces of broccoli sprouts or 2.5 ounces of alfalfa sprouts each day for two months.
Broccoli, a cruciferous vegetable, contains high levels of the protective phytochemical sulforaphane. Alfalfa is not a cruciferous vegetable and contains no sulforaphane.
At the beginning and end of the study, the researchers analyzed participant stool samples for a chemical called HpSA, known to be a reliable marker of infection with the Heliobacter pylori bacterium. H. pylori causes chronic inflammation of the stomach lining, significantly increasing the risk of stomach cancer and duodenal or stomach ulcers.
While 25 to 30 percent of people in the United States carry the bacteria in their stomachs, 80 percent show no symptoms of the infection. Infection rates are much higher in Japan, at nearly 90 percent, due in part to crowding.
The researchers found that among those who ate broccoli sprouts, HpSA levels decreased 40 percent by the end of the experiment. Participants were then told to stop eating broccoli sprouts. After another two months, HpSA levels had returned to pre-study levels.
Consumption of alfalfa sprouts had no effect on HpSA levels.
“H. pylori is a known carcinogen,” Fahey said. “The fact that we were able to reduce the effects of an infectious agent that is also a carcinogen gives us hope that if someone were to eat broccoli sprouts or broccoli regularly, it would reduce levels of H. pylori and, over a period of many years, reduce the chance that they would get that cancer. It is not proven, but the results are highly suggestive.”
The researchers also found that inflammation levels in the stomach were reduced by consumption of broccoli sprouts.
“The fact that the levels of infection and inflammation were reduced suggests the likelihood of getting gastritis and ulcers and cancer is probably reduced,” Fahey said.
“The evidence is all pointing toward broccoli or broccoli sprouts being able to prevent cancer in humans.”
The researchers believe that much of broccoli’s protective benefit comes from its high levels of sulforaphane. In addition to functioning as an antibiotic, this chemical stimulates the body to reduce a number of enzymes with different health benefits. Prior research has shown that some of these enzymes protect the skin from sun damage, while others act to reduce inflammation or prevent heart disease.
In a second experiment, the same team of researchers fed H. pylori-infected mice either plain water or broccoli-sprout smoothies for eight weeks. They then examined the animals’ stomachs for levels of H. pylori. Infection levels had not changed in mice drinking water, but were significantly reduced in the broccoli group. When the researchers genetically engineered another group of mice for inability to activate certain protective enzymes, however, a diet of broccoli-sprout smoothies had no effect on H. pylori infection.