Recent tests on cells, tissues and mice show that a broccoli compound, sulforaphane, blocks a key destructive enzyme that damages cartilage. Sulforaphane, a sulfur compound, has also been shown to kill cancer stem cells, thereby slowing tumor growth. It also normalizes DNA methylation, which is important in regulating gene expression.
Specifically, it appears that broccoli contains the necessary ingredients to switch on genes that prevent cancer development, and switch off other genes that help it spread.
Research has shown that fresh broccoli sprouts are far more potent, allowing you to eat far less in terms of quantity. Sprouts consistently contain 20 to 50 times the amount of chemoprotective compounds found in mature broccoli heads.