WASHINGTON (AP) - Remember when your mother told you to eat broccoli? Scientists say they've proved mother knows best.
Dr. Paul Talalay of Johns Hopkins University School of Medicine said in a paper published today that studies in his lab show broccoli is rich in sulforaphane, a chemical that works as a powerful anti-cancer compound in laboratory mice.
Studies have shown that a diet rich in cruciferous vegetables such as broccoli, Brussels sprouts, cabbage and cauliflower, can lower the risk of cancer of the bowel, stomach and breast. How those vegetables caused the effect wasn't clear.
Now, Dr. Talalay said, it appears that at least one anti-cancer ingredient in the vegetables is sulforaphane. It works by causing cells to expel cancer-causing toxins.
He said this is the first time a high-potency compound has been isolated from vegetables and has been shown to accelerate the detoxification process in cells.
Dr. Talalay said his team isolated sulforaphane from broccoli, then fed it to a group of mice. When cells in the mice were examined after five days, the scientists found that the chemical had triggered enzymes known to neutralize carcinogens within cells.
Research, Dr. Talalay said, will shift to the long-term cancer-fighting effects of the chemical. "Our prediction is that sulforaphane will block tumor formation in animals and presumably in man," he said.
Nutrition and medical scientists are trying to find ways to prevent cancer through a diet rich in foods that have anti-tumor properties.
In earlier studies, Dr. Talalay said, he and others have shown that certain proteins in cells, called Phase I enzymes, can take innocent chemicals and turn them into carcinogens, or compounds that can give rise to cancer by disrupting the genetic pattern in cells.
Other proteins, called Phase 2 enzymes, he said, tend to block formation of carcinogens.
Sulforaphane, he said, is a potent activator of Phase 2 enzymes.
"There is mounting evidence that if you are able to raise the Phase 2 enzymes, this will divert the carcinogenic compounds from damaging the [genes]," Dr. Talalay said. "By tilting this balance toward Phase 2 enzymes, we can achieve protection from cancer."
The Hopkins researchers will conduct tests to determine how much broccoli must be consumed to establish an effective anti-cancer level of sulforaphane in cells.
Over a decade of research has been done on cruciferous vegetables and there are large databases that confirm that cruciferous vegetables substantially reduce the risk of disease, specifically cancer. Studies show substances in these vegetables that have anti-cancer properties which cause the body to speed up production of enzymes, therefore being capable of neutralizing cancer agents. The studies also show these prevent damage to our DNA and slow the aging process. In women, metabolic processes are regulated which eliminate the bad (and maintain the good) estrogen, therefore substantially reduce the risk of breast cancer. Shortly after the NCI study was released, John Hopkins School of Medicine revealed similar studies.
Due to these study results, the National Cancer Institute, the American Cancer Society, the National Academy of Sciences, the U.S. Department of Agriculture, John Hopkins School of Medicine and the FDA have all reached out to inform the public of the anti-cancer compounds found in cruciferous vegetables, and are advocating the daily consumption of these vegetables. The average American has been eating only 4 and one half pounds of these vegetables per year!
Broccoli sprouts join war on cancer
The Sunday Telegraph
SUPER BROCCOLI, said to have powerful properties which help to prevent cancer, could soon be on
sale in supermarkets. The new form of the vegetable contains very high concentrations of the compound sulphoraphane, which acts as an anti-cancer agent by encouraging the body to attack dangerous chemicals that cause malignancy.
The chance discovery was made after American scientists in Baltimore found that broccoli sprouts harvested after just three days contained up to 50 times the concentration of sulphoraphane as the mature plant. The development was welcomed last night by British researchers who since 1992, when the protective qualities of sulphoraphane were first discovered, have been investigating how the anti-cancer properties of vegetables can be controlled.
Resembling bean sprouts, the new broccoli is grown in laboratories using normal seeds. Although not genetically modified, it contains consistently high concentrations of the anti-cancer ingredients and has a pleasant, tangy taste. The team behind it believe the broccoli could be on supermarket shelves by next year.
Paul Talalay, a professor of pharmacology at the Johns Hopkins School of Medicine in Baltimore, who led the research, has for 20 years been concentrating on "chemoprotection", the attempt to boost the body' s own defences against carcinogens.
"We started growing these seeds in the laboratory and made the totally unexpected discovery that they contained enormously high quantities of the substances that boost the protective enzymes," Prof Talalay said.
"This a major milestone in a very long organised research programme to develop strategies for preventing cancer."
The new sprouts would enable consumers to eat only a fraction of the amount of shop-bought broccoli to produce the same effect, he added. The development has excited researchers at the Institute of Food Research in Norwich, who are investigating a range of "super vegetables".
A discussion on "super broccoli" will be held at the IFR this week as part of its session of open days.
1997 © Telegraph Group Limited
CATHERINE ELSWORTH, Broccoli sprouts join war on cancer., The Sunday Telegraph, 09-28-1997,
pp 08.