Eating raw broccoli may combat cancer…When you chew broccoli, its cells rupture, releasing an enzyme that produces a class of chemicals called sulphoraphanes. Nathan Matusheski, a researcher at the University of Illinois, Urbana-Champaign, crushed raw broccoli in the lab to mimic chewing, and tested the resulting mush. Matusheski says that in common supermarket broccoli, 20 per cent of the sulphoraphanes are the anti-carcinogenic kind, which have an extra sulphur atom in each molecule. The rest lacks this crucial sulphur and has no cancer-fighting capability. But when he tested broccoli that had been heated to 60 °C, he found the relative levels were reversed, favoring the anti-cancer compound. A protein in broccoli called ESP plays a role in pushing the balance toward the sulphur-poor sulphoraphane. Matusheski confirmed that heating the broccoli destroys the ESP, tipping the balance in favor of the beneficial sulphoraphane. But cooking broccoli conventionally does not help, as the enzyme that produces sulphoraphanes in the first placed is also destroyed.

Newscientist.com, 4/12/03