While researching nutrition strategies to put my body in the strongest possible position to fight cancer again, cruciferous vegetables consistently rose to the top. (I still have to slow down to pronounce it correctly: [kroo-sif-er-uhs].)

This does not mean these foods “kill cancer.” They don’t. What the evidence supports is more restrained: cruciferous vegetables contain compounds that can modulate pathways involved in cancer growth, detoxification, inflammation, and cellular stress. In other words, they may help tilt the terrain in your favor—but they are not a knockout punch. More like pinning your opponent down briefly, knowing you can’t hold them there forever.

This wasn’t entirely new to me. When I first began fighting colorectal cancer, I deliberately added more broccoli to my diet. What I didn’t do at the time was research how much to eat—or how to prepare it properly. I assumed broccoli was broccoli. That assumption was wrong.

Cruciferous vegetables contain precursor compounds that can be converted into biologically active molecules—most notably sulforaphane and indole-3-carbinol (which further converts into compounds like DIM). Broccoli sprouts contain the highest concentrations of sulforaphane precursors, while mature broccoli still provides meaningful amounts when prepared correctly.

Preparation matters because these benefits depend on an enzyme called myrosinase. When you cut or chew raw broccoli, myrosinase converts inactive precursors (like glucoraphanin) into sulforaphane and indoles. Heat can deactivate this enzyme.

Two preparation steps are critical:

1. Cut first, then wait.
After chopping broccoli (or other cruciferous vegetables), let it rest for 5–10 minutes before cooking. This allows myrosinase to do its job before heat is applied.

2. Avoid excessive heat.
High or prolonged heat deactivates myrosinase and significantly reduces sulforaphane formation. Light steaming is far better than boiling or aggressive stir-frying.

This realization forced me to confront a long-standing habit. One of my favorite meals—especially now during treatment—is a simple stir-fry. My method has always been efficiency-driven: chop the hardest vegetables first, throw them straight into the wok, then continue chopping while they cook.

That works fine for texture. It works terribly for broccoli chemistry.

When broccoli stems hit the pan seconds after being cut, there is no time for myrosinase activation—no 5–10 minute window, just heat. In effect, I’ve been consistently stripping broccoli of much of the very benefit I thought I was getting.