Kale or borecole is a form of cabbage (Brassica oleracea Acephala Group), green or purple, in which the central leaves do not form a head. It is considered to be closer to wild cabbage than most domesticated forms. The species Brassica oleracea contains a wide array of vegetables including broccoli, cauliflower, collard greens, and brussels sprouts. The cultivar group Acephala also includes spring greens and collard greens, which are extremely similar genetically.
Kale is considered to be a highly nutritious vegetable with powerful antioxidant properties; kale is considered to be anti-inflammatory.
Kale is very high in beta carotene, vitamin K, vitamin C, lutein, zeaxanthin, and reasonably rich in calcium.
Kale, as with broccoli and other brassicas, contains sulforaphane (particularly when chopped or minced), a chemical believed to have potent anti-cancer properties. Boiling reduces the level of the anti-cancer compounds, however, steaming, microwaving, and stir frying does not result in significant loss. Along with other brassica vegetables, kale is also a source of indole-3-carbinol, a chemical which boosts DNA repair in cells and appears to block the growth of cancer cells. Kale is also a good source of carotenoids.