Kale or borecole (Brassica oleracea Acephala Group) is a vegetable with green or purple leaves, 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 variety 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. Pieris rapae is one of the most well known pests of the plant.
Kale is very high in beta carotene, vitamin K, vitamin C, and rich in calcium.
Kale is a source of two carotenoids, lutein and zeaxanthin.
Kale, as with broccoli and other brassicas, contains sulforaphane (particularly when chopped or minced), a chemical with potent anti-cancer properties.
Boiling decreases the level of sulforaphane; however, steaming, microwaving, or stir frying do 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 has been found to contain a group of resins known as bile acid sequestrants, which have been shown to lower cholesterol and decrease absorption of dietary fat. Steaming significantly increases these bile acid binding properties.