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Cancer Preventing Properties of Broccoli

Special Feature: Broccoli

Released Sept 15, 1997 via JHMI

Johns Hopkins scientists have found a new and highly concentrated source of sulforaphane, a compound they identified in 1992 that helps mobilize the body's natural cancer-fighting resources and reduces 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 Pharmacology.

Photo: Keith Weller
Dr. Paul Talalay displays broccoli sprouts.

Talalay's research team fed extracts of the sprouts to groups of 20 female rats for five days, and exposed them and a control group that had not received the extracts to a carcinogen, dimethylbenzanthracene. The rats that received the extracts developed fewer tumors, and those that did get tumors had smaller growths that took longer to develop.

In a paper published in tomorrow's issue of the Proceedings of the National Academy of Sciences, Talalay and his coworkers describe their successful efforts to build on their 1992 discovery of sulforaphane's chemoprotective properties. Work described in the study is the subject of issued and pending patents.

A systematic search for dietary sources of compounds that increase resistance to cancer-causing agents led the Hopkins group to focus on 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.

Photo: Keith Weller
Dr. Jed Fahey examines young sprouts.

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.

However, tests reported in the new study showed that glucoraphanin levels were highly variable in broccoli samples, and there was no way to tell which broccoli plants had the most without sophisticated chemical analysis.

"Even if that were possible, people would still have to eat unreasonably large quantities of broccoli to get any significant promotion of Phase 2 enzymes," Talalay says.

Clinical studies are currently 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.

Talalay founded 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.

"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.

Scientists currently need to continue to develop new ways of detecting and treating cancer once it is established, but it also makes sense to focus more attention on efforts to prevent cancer from arising," he adds.

Fahey and Yuesheng Zhang, M.D., Ph.D., a postdoctoral fellow, are also authors on the PNAS paper.

Work in Talalay's laboratory is supported by the National Cancer Institute, philanthropic contributions to Brassica Chemoprotection Laboratory, and grants from the Cancer Research Foundation of America and the American Institute for Cancer Research.

Talalay is establishing the Brassica Foundation, a foundation that will test and certify chemoprotective vegetables such as sprouts to raise funds for chemoprotection research.

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May 30, 2002


Sulforaphane, a compound found in broccoli and broccoli sprouts, kills the bacterium known to cause ulcers and stomach cancer, according to laboratory research from the Johns Hopkins School of Medicine and the French National Scientific Research Center. The findings appear in the May 21 online edition of the Proceedings of the National Academy of Sciences and were reported by the Washington Post.

Jed Fahey, MS, a plant physiologist in the Department of Pharmacology and Molecular Sciences at the Johns Hopkins School of Medicine, is the study's lead author. He is also affiliated with the Center for Human Nutrition at the Johns Hopkins Bloomberg School of Public Health. Patrick Dolan, BS, and Thomas Kensler, PhD, from the Department of Environmental Health Sciences at the Johns Hopkins Bloomberg School of Public Health, also contributed to the study.

Other authors of the report include Alain Lozniewski, Xavier Haristoy, and Isabelle Scholtus of the French National Scientific Research Center. Katherine Stephenson and Paul Talalay, MD, are with the Johns Hopkins School of Medicine.

For more information:

Proceedings of the National Academy of Sciences
School of Medicine News Release
Washington Post Article

of Medicine: Joanna Downer @ 410-614-5105 or

of Public Health: Tim Parsons @ 410.955.6878 or



Health Newsfeed # 597


(Stations please note: this story is embargoed for use until Tuesday, Sept. 16)

Five years ago Johns Hopkins scientists identified a cancer-fighting compound called sulforaphane. It's found in some vegetables; broccoli is an especially rich source. But people would have to consume pounds of it every week to obtain the anti-cancer benefits.

This week Hopkins scientists announced they've discovered a new and highly concentrated source of the compound: three day old broccoli sprouts. Project director Dr. Paul Talalay.}

The young sprouts that we have found contain 30 to 50 times higher concentrations, and will make it possible to reduce the total amount of intake of vegetables that an individual needs to protect himself. :14

Lead study author Jed Fahey notes that unlike mature broccoli, sprouts need only light and water, not soil.

A comparable amount of chemoprotective activity can be developed in sprouts in a very small area, a very small room. :06

Broccoli sprouts are not yet sold commercially. At the Johns Hopkins Medical Institutions, I'm Tom Haederle reporting. Copyright 1997 The Johns Hopkins University. All rights reserved.


Press Release May 28, 2002

Contact: Emilio Williams
Telephone: 1-410-502-3216
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Broccoli Component Kills Bacterial Cause of Ulcers and Stomach Cancer; Laboratory Finding Points to Possible Economical Treatment of Infection

A bacterium responsible for the vast majority of stomach cancers, a leading cause of cancer death worldwide, and ulcers may have met its match, scientists from Johns Hopkins and the French National Scientific Research Center report in the May 28 edition of the Proceedings of the National Academy of Sciences.

The research team discovered that sulforaphane, a compound found in broccoli and broccoli sprouts, kills the bacterium in laboratory studies. The findings should lead quickly to clinical trials to see whether dietary intake of vegetables containing sulforaphane can relieve infection, the researchers say.

In all but 15 to 20 percent of cases, combinations of powerful antibiotics can kill helicobacter pylori, the bacterium that was recognized 20 years ago as the cause of debilitating stomach ulcers and often fatal stomach cancers. Unfortunately, the regions of the world where the infection is most common are the same places where using antibiotics is most economically and logistically difficult.

"In some parts of Central and South America, Africa and Asia, as much as 80 percent to 90 percent of the population is infected with helicobacter, likely linked to poverty and conditions of poor sanitation," says study leader Jed Fahey, a plant physiologist in the Department of Pharmacology and Molecular Sciences at the Johns Hopkins School of Medicine. "If future clinical studies show that a food can relieve or prevent diseases associated with this bacterium in people, it could have significant public health implications in the United States and around the world."

In their laboratory experiments, the scientists discovered that purified sulforaphane even killed helicobacter that was resistant to commonly used antibiotics. They also proved that sulforaphane can kill the bacterium whether it's inside or outside cells. In people, cells lining the stomach can act as reservoirs of helicobacter, making it more difficult to get rid of the infection, says Fahey.

Even though the pure compound kills helicobacter efficiently, it remains to be seen whether dietary sources of sulforaphane (broccoli or broccoli sprouts, for instance) have similar effects. If so, vegetables native or adapted to various regions could be used by local populations to reduce helicobacter infection, notes Fahey, who has compiled a list of vegetables that contain sulforaphane or related compounds.

"We've known for some time that sulforaphane had modest antibiotic activity," says Fahey, who is also affiliated with the Center for Human Nutrition at the Johns Hopkins Bloomberg School of Public Health. "However, its potency against helicobacter, even those strains resistant to conventional antibiotics, was a pleasant surprise."

Sulforaphane was initially isolated from broccoli at Johns Hopkins because of its ability to protect cells against cancer by boosting their production of "phase 2" enzymes, a family of proteins that detoxify certain cancer-causing agents and damaging free radicals. However, the compound's antibiotic abilities are not well understood and are likely to occur through some other mechanism, says Fahey.

Sulforaphane can protect against chemically induced stomach cancer in mice, the research team also found, but more studies are needed to know whether it can do the same against helicobacter-induced stomach cancer and whether dietary sulforaphane, rather than pure sulforaphane, will do the trick.

The French group was led by Alain Lozniewski. Other authors on the report are Xavier Haristoy and Isabelle Scholtus of the French National Scientific Research Center; Patrick Dolan and Thomas Kensler of the Johns Hopkins Bloomberg School of Public Health; and Katherine Stephenson and Paul Talalay of the Johns Hopkins School of Medicine.