From wiki:

Kale is considered to be a highly nutritious vegetable with powerful antioxidant properties and is anti-inflammatory.[1]
Kale is very high in beta carotene, vitamin K, vitamin C, lutein, zeaxanthin, and reasonably rich in calcium. Because of its high vitamin K content, patients taking anti-coagulants such as warfarin are encouraged to avoid this food since it increases the vitamin K concentration in the blood, which is what the drugs are often attempting to lower. This effectively raises the effective dose of the drug.
Kale, as with Broccoli and other brassicas, contains sulforaphane, a chemical believed to have potent anti-cancer properties, particularly when chopped or minced
http://en.wikipedia.org/wiki/Kale

I am embarrassed...especially since nutritian is part of what I do for a living. Can I blame living in the south where collard and turnip greens are plentiful?