New Broccoli Study

By George Grow

This is the VOA Special English SCIENCE REPORT.

The vegetable broccoli has a natural substance that may prevent some kinds of cancer. Recently, American scientists reported that not all broccoli is equal in fighting cancer. The scientists examined many different kinds of broccoli plants. They attempted to activate an enzyme in the plants that may protect against some cancers.

The scientists discovered major differences among the broccoli tested. Some plants had very little of the cancer-fighting substance. Other plants had large amounts of the substance. The Journal of the American Society for Horticultural Science published the findings.

Earlier studies have shown that people who eat vegetables like broccoli have lower rates of colon and rectal cancers. Broccoli plants and young seedlings have a chemical called glucoraphanin. They also contain a product of the chemical, called sulforaphane. Sulforaphane causes the production of enzymes that slow the growth of cancer tumors in laboratory animals.

Scientists at Johns Hopkins University in Baltimore, Maryland discovered the cancer-fighting agent in broccoli nine years ago. Johns Hopkins scientists joined with the United States Agricultural Research Service to organize the new study. A few years ago, the Research Service's Vegetable Laboratory in Charleston, South Carolina grew more than seventy kinds of broccoli. The scientists then examined the chemicals in each plant.

They observed extreme differences in glucoraphanin levels and the activity of enzymes in the broccoli tested. Some kinds of broccoli had very small amounts of the chemical. However, others had levels about thirty times greater.

Scientists want to learn more about the different levels of glucoraphanin and sulforaphane in broccoli plants. They hope the research will help them develop new kinds of broccoli with greater levels of the protective substances. They say eating such improved broccoli might result in more effective, natural defenses against cancer.

American doctors say eating fruits and vegetables, including broccoli, is important for health. The National Cancer Institute says people should eat at least five servings of fruits and vegetables every day.

This VOA Special English SCIENCE REPORT was written by George Grow.