Broccoli Sprouts May Prevent
Gastritis, Ulcers and Stomach Cancers
Citing their new "demonstration of principle" study, a
Johns Hopkins researcher and an international team of scientists
showed 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.
"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 Jed W. Fahey, M.S., Sc.D.,
an author of the paper who is a nutritional biochemist in the
Lewis B. and Dorothy Cullman Cancer Chemoprotection Center at
the Johns Hopkins University School of Medicine.
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. The study,
published April 6 in Cancer Prevention Research, builds
on earlier test-tube and mouse studies at Johns Hopkins 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.
In the new report, the team also shows that when H. pylori-infected
mice sipped broccoli-sprout smoothies for eight weeks, there was
up to a fourfold increase in the activity of two of these key
enzymes that protect cells against oxidative damage. In addition,
the number of Helicobacter bacteria in the mice's stomachs decreased
by almost a hundredfold it did not change in infected control
animals that drank plain water. The researchers also noted a greater
than 50 percent reduction in inflammation of the primary target
of this bacterium – the body of the stomach – in treated
mice but not in controls.
In a related experiment, the team fed the same dose of broccoli
sprouts for the same amount of time to H. pylori-infected
mice that had been genetically engineered to lack the Nrf2 gene
that activates protective enzymes. "These knock-out mice
didn't respond," Fahey says, which confirms previous findings
for a role of Nrf2 in protection against H. pylori-induced
inflammation and gastritis.
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.
Research strongly suggests that the bacteria also are linked to
high rates of stomach cancer in some countries, that strains resistant
to standard antibiotics are prevalent, and that multiple courses
of standard antibiotics do not always eliminate the infection.
Working in Japan where there is high incidence of chronic H.
pylori-infection, the research team gave 25 H. pylori-infected
subjects two and a half ounces (70 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 used
breath tests to assess colonization by H. pylori bacteria
and blood tests to judge the severity of inflammation in the stomach
lining; in addition, they looked for antigens in stool samples
to help determine the extent of the infections.
"We know that a dose of a couple ounces a day of broccoli
sprouts is enough to elevate the body's protective enzymes,"
Fahey says. "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."
In disclosure of a potential conflict of interest, Fahey is a
cofounder in a company that is licensed by The Johns Hopkins University
to produce broccoli sprouts. A portion of the proceeds is used
to help support cancer research, but no such funds were provided
to support this study.
"It's exciting that a chronic bacterial infection that poses
great hazards to hundreds of millions of people globally can be
ameliorated by a specific dietary strategy," says Paul Talalay,
M.D., John Jacob Abel Distinguished Service Professor of Pharmacology
and Experimental Therapeutics and director of the Lewis B. and
Dorothy Cullman Cancer Chemoprotection Center at Johns Hopkins'
Institute for Basic Biomedical Sciences.
Talalay directs the lab where, in 1992, his team discovered the
health-promoting properties of sulforaphane. A longtime proponent
of cancer prevention and chemoprotection, Talalay eats fresh broccoli
sprouts regularly, as does Fahey.
"I like them," Fahey says. "I eat them all the
time, but not every day. Variety is the spice of life: I eat blueberries
on the other days."
In addition to Fahey, the authors of the paper are Akinori Yanaka,
Atsushi Fukumoto, Mari Nakayama and Souta Inoue, Tokyo University
of Science, Japan; Masayuki Yamamoto, Songhua Zhang, Masafumi
Tauchi, Hideo Suzuki and Ichinosuke Hyodo, University of Tsukuba,