Is sulforaphane effective against cancer?

Short Answer: Sulforaphane is the most potent natural Nrf2 activator, with strong preclinical evidence showing anti-cancer effects through multiple mechanisms. Small human trials show biomarker improvements, but no Phase III cancer trials exist.

Evidence Level: moderate

Detailed Answer

Sulforaphane, an isothiocyanate from cruciferous vegetables (highest in broccoli sprouts), activates the Nrf2 pathway — the master regulator of >200 cytoprotective genes. Anti-cancer mechanisms include: Phase II enzyme induction (accelerating carcinogen detoxification), HDAC inhibition (epigenetic anti-cancer effect), NF-κB suppression (anti-inflammatory), cell cycle arrest, and apoptosis induction. Key human data: a broccoli sprout beverage trial in China (Egner et al., 2014, Cancer Prev Res) showed 61% increased excretion of the airborne carcinogen benzene. The SULForaphane trial for prostate cancer (ESCAPE, NCT01950143) showed PSA stabilization. Bioavailability note: myrosinase enzyme (from raw broccoli or mustard seed) is required to convert glucoraphanin to sulforaphane — cooking destroys myrosinase. Supplements should contain both glucoraphanin and myrosinase.

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