Broccoli Sprouts Chemopreventive Properties
By Sean Henahan, Access Excellence
 Baltimore,
MD (9/15/97) Broccoli sprouts appear to have signficant chemoprotective
effects against cancer, according to researchers at Johns Hopkins
University. A new study found remarkably high levels of sulforaphane, a
compound known to stimulate the body's natural cancer-fighting resources
and reduce the risk of developing cancer.
"Three-day-old broccoli sprouts consistently contain 20 to 50 times
the amount of chemoprotective compounds found in mature broccoli heads,
and may offer a simple, dietary means of chemically reducing cancer risk,"
says Paul Talalay, M.D., J.J. Abel Distinguished Service Professor of Pharmacolog
at Johns Hopkins.
Talalay and colleagues base their conclusions on animal studies in which
rats were fed extracts of the sprouts and exposed to a carcinogen, dimethylbenzanthracene.
The rats developed fewer tumors, and those that did get tumors had smaller
growths that took longer to developed compared with control animals, the
scientists report.
The discovery followed a determined campaign by the Hopkins team to
locate naturally occurring compounds in edible plants that mobilize Phase
2 detoxification enzymes. These enzymes neutralize highly reactive, dangerous
forms of cancer-causing chemicals before they can damage DNA and promote
cancer.
Sulforaphane "is a very potent promoter of Phase 2 enzymes," says Jed
Fahey, plant physiologist and manager of the Brassica Chemoprotection Laboratory
at Hopkins, and broccoli contains unusually high levels of glucoraphanin,
the naturally-occurring precursor of sulforaphane.
The researchers found that glucoraphanin levels varied widely among
broccoli samples. One might have to eat mountains of mature broccoli to
aborb beneficial amounts of the compound. This is the best part of the
discvoery of greatly increased levels in broccoli sprouts. Not only do
they allow you to consume meaningful elves of the compound, the taste is
much milder than that of mature broccoli.
Clinical studies are already under way to see if eating a few tablespoons
of the sprouts daily can supply the same degree of chemoprotection as one
to two pounds of broccoli eaten weekly. The sprouts look and taste something
like alfalfa sprouts, according to Talalay.
"Man-made compounds that increase the resistance of cells and tissues
to carcinogens are currently under development, but will require years
of clinical trials to determine safety and efficacy," Talalay notes. "For
now, we may get faster and better impact by looking at dietary means of
supplying that protection. Eating more fruits and vegetables has long been
associated with reduced cancer risk, so it made sense for us to look at
vegetables.
Talalay is the founder of the Brassica Chemoprotection Laboratory, a
Hopkins center that focuses on identifying chemoprotective nutrients and
finding ways to maximize their effects. Brassica is a plant genus more
commonly known as the mustard family, and includes in addition to broccoli,
Brussels sprouts, cabbage, kale, cauliflower and turnips. A number of different
cancer-fighting compounds have been isolated from plants in this genus.
The study appears in the September 16, 1997 issue of the Proceedings
of the National Academy of Sciences,
| 
Science Updates Index
