How exactly collard greens’ sulfur-containing phytonutrients (phyto = plant) prevent a wide variety of cancers is not clear, but research points to the ability of components known as “glucosinolates” and “cysteine sulfoxides” to activate detoxifying enzymes in the liver that neutralize potentially carcinogenic (cancer-causing) substances.
1 cup of cooked Collard Greens contains:

704 mcg of Vitamin K
5945 [...]

Studies show that cruciferous vegetables, like broccoli, that contain the largest concentrations of health promoting sulfur compounds, increase the liver’s ability to produce enzymes that neutralize potentially toxic substances.  Broccoli is also a wonderful source of the powerful phytonutrient antioxidants Lutein and Zeaxanthin, which are carotenoids that are concentrated in the lens of the eye.  [...]