Broccoli Helps Fight Cancer, Researchers Say

Broccoli contains substances that can block or retard formation of breast tumors in rats by promoting anti-cancer enzymes, medical researchers at Johns Hopkins University report.

In a study to be published in the Proceedings of the National Academy of Sciences today, the scientists said doses of compounds that are found in broccoli and in some other vegetables provided cancer protection for a group of rats that had been exposed to powerful cancer-causing chemicals.

Dr. Paul Talalay, a Hopkins researcher who is co-author of the study, said Monday that sulforaphane and some related compounds are apparently able to amplify the body’s own defenses against chemicals that can lead to cancer.

“Most cancer-causing chemicals are themselves innocuous until they enter cells where they are converted to enzymes which are highly reactive and are capable of initiating tumor formation,” said Talalay.

Sulforaphane and its chemical cousins, he said, cause the body to produce another type of enzyme that blocks the cancer-causing action of the first enzyme.

In the study, Talalay and his colleagues exposed 145 rats to DMBA, a powerful cancer-causing chemical. Twenty-five of the rats were used as controls and received no drug treatment.

At the end of 50 days, 68% of the control rats had developed mammary tumors, but only about 26% of those receiving high doses of sulforaphane developed cancer. Similar results were found for a related substance, called compound 2. Other related compounds were effective to a lesser degree.

Talalay emphasized that the vegetable compound seems to work only as a cancer preventer and has no effect on tumors that have already started.