April 3, 2000 (Petaluma, Calif.) -- Who would have thought that of all the brightly colored exotic offerings in the produce aisle -- from curvy, golden-yellow peppers to inky, purple eggplants -- homely broccoli would become the superstar?
It's true: In the category of most healthful vegetable, this cruciferous contender wins all the top honors. This past February, when the American Journal of Clinical Nutrition published a paper that listed foods most likely to prevent colon cancer, what stood out? Broccoli. Scientists at the Harvard School of Public Health in Boston published an article in the same journal last October and noted that broccoli, along with spinach, helped to minimize risk for cataracts. When another team of Harvard scientists looked at how diet might protect against stroke, broccoli's benefits again came to the fore, in research published in the October 6, 1999 issue of the Journal of the American Medical Association.
Nutritious -- and Then Some
When it comes to basic nutrients, broccoli is a mother lode. Ounce for ounce, boiled broccoli has more vitamin C than an orange and as much calcium as a glass of milk, according to the USDA's nutrient database. One medium spear has three times more fiber than a slice of wheat bran bread. Broccoli is also one of the richest sources of vitamin A in the produce section.
But the real surprise is this vegetable's potent cancer-fighting ingredients. At the Johns Hopkins University School of Medicine in Baltimore, food chemist Paul Talalay, MD, has gone so far as to name his lab after Brassica, the genus that includes broccoli and cauliflower. Talalay and his team at the Brassica Chemoprotection Laboratory have discovered that broccoli is rich in substances called isothiocyanates -- chemicals shown to stimulate the body's production of its own cancer-fighting substances, called "phase two enzymes." According to Talalay, these enzymes, in turn, neutralize potential cancer-causing substances before they have a chance to damage the DNA of healthy cells.
To test broccoli's cancer-fighting power, Talalay fed rats hearty servings of the vegetable for a few days and then exposed them to a potent carcinogen known to trigger a form of breast cancer in the animals. Broccoli-munching rats were half as likely to develop tumors as animals on standard chow, according to results published in the April 1994 Proceedings of the National Academy of Science. "Even those rats that did develop cancer ended up with fewer and smaller tumors, which is an important advantage in itself," says Talalay. More recently, scientists at Tokyo's Graduate School of Agriculture have shown that isothiocyanates can block the growth of melanoma skin cancer cells, according to findings published in 1999 in the journal Nutrition and Cancer.
Good News for Broccoli Haters
If you don't like broccoli, take heart: In 1997, Talalay and his researchers at Hopkins discovered to their surprise that broccoli sprouts, the week-old seedlings of the mature plant, are exceptionally rich in a form of isothiocyanate called sulforaphane -- 10 to 100 times as rich as broccoli itself, in fact. More and more markets now carry the tender shoots, which are delicious on sandwiches and salads.
And keep in mind that broccoli is just one of many members of the cruciferous vegetable family, which includes cauliflower, kale, cabbage, brussels sprouts, and bok choy -- all of which appear to help protect against cancer. When scientists at the World Cancer Research Fund reviewed 206 human and 22 animal studies, they found convincing evidence that cruciferous vegetables in general lowered risk for many forms of the disease, including tumors of the stomach, esophagus, lung, oral cavity and pharynx (throat), endometrium (lining of the uterus), pancreas, and colon.
How to Crucify Your Diet
Need ideas for adding more of these vegetables to your diet? Cauliflower makes a delicious addition to pasta primavera. Use penne pasta and you can boil the cauliflower and the noodles together -- both require the same amount of cooking time. Chopped red cabbage is a great addition to salads or chili. And if you're not familiar with kale, try it in the savory Portuguese soup called caldo verde: Peel and finely chop two pounds of boiling potatoes and boil for two minutes. Then add one bunch of chopped kale (about 6 to 8 cups) and cook for two more minutes. Season with a little salt and a splash of olive oil and you're ready to eat.