The enzyme-inducing abilities of samples taken from 22 varieties of fresh and 7 brands of frozen mature broccoli vary greatly. Only sophisticated scientific measurements can determine the concentrations. But fresh broccoli sprouts offer an alternative. One can get away with eating 10 to 100 times lower quantities. Three day old sprouts have the additional advantage that they're far more uniform in their potency.
Broccoli sprouts look and taste something like alfalfa sprouts, according to the researchers.
The report also notes that small quantities of broccoli sprout extracts markedly reduced the size of rat mammary tumors that were induced by chemical carcinogens. The interesting aspect of chemoprotection strategies is that they're almost never organ-specific. At the present time, broccoli sprouts are not being grown commercially. However you can grow them yourself quite easily. Non-organic seeds can probably be purchased through farm supply stores or other seed catalogs.