Broccoli, Broccoli Sprouts Deter Cancers in Rats
November 15, 2001
broccoli--containing hundreds of times more selenium than grocery store
varieties--protected laboratory rats against mammary tumors in a
Roswell Park Cancer
Institute laboratory at Buffalo, N.Y.
And high-selenium broccoli sprouts protected rats against precancerous
lesions in the colon in an Agricultural
Research Service laboratory in Grand Forks, N.D. Whether the findings
translate to humans, either for efficacy or safety, will require further study.
John W. Finley, a nutritionist at ARS'
Grand Forks Human Nutrition Research
Center, and colleagues recently reported the findings together with Clement
Ip at Roswell Park, Buffalo; Phil D. Whanger at Oregon State University, Corvallis, and others.
The broccoli heads and sprouts used in these studies were produced for
experimental purposes and are not available commercially. The rats were given
enough to approximate a human dose of about 200 micrograms daily. Several human
studies have shown that taking a 200 mcg-selenium supplement--thats about
three times the Reference Daily Intake--can reduce the incidence of several
types of cancer. But it will not reverse tumors once they develop.
The researchers enriched broccoli because it stores selenium in a unique
form, called SeMSC for short. Its easy for people and animals to convert
SeMSC into the active anticancer agent compared to a much longer process for
other selenium compounds. In earlier studies, when Finley and co-workers
challenged rats with known carcinogens, the animals that had eaten the
high-selenium broccoli had far fewer precancerous colon lesions than the groups
given selenium salts--selenate or selenite.
In the latest studies, Ip and coworkers at the Buffalo lab found a similar
protective effect of high-selenium broccoli against mammary tumors, using a rat
model for such tumors. The rats got about 30 times more selenium from the
specially grown broccoli than they would in a standard diet.
Meanwhile, Finley and coworkers at the Grand Forks lab tested high-selenium
broccoli sprouts in a rat model for colon cancer and saw the same protective
effect they had earlier gotten with high-selenium broccoli. Found in many
health food stores, broccoli sprouts are known to be rich in other anticancer
compounds, but commercially available broccoli sprouts are not enriched in
ARS is the chief scientific research agency of the
U.S. Department of Agriculture.