Broccoli and its cruciferous cousins (kale, collards, cauliflower, cabbage) are world-famous for their cancer-fighting prowess and much of their anti-cancer punch is attributed to a plant compound called sulforaphane. The formation of sulforaphane in cruciferous veggies requires the activity of an enzyme called myrosinase.
Unfortunately, myrosinase is heat sensitive, so cooking this family of veggies diminishes their myrosinase, and thus their sulforaphane content. Scientists have recently determined that you can circumvent this problem by adding spicy condiments like horseradish sauce, wasabi, or mustard to your broccoli or other cruciferous veggies before serving them. These spicy foods also contain myrosinase, which will ensure optimal sulforaphane formation and absorption.