The name kale originates from Northern Middle English cale (compare Scots kail and German Kohl) for various cabbages.

[7] Kale originated in the eastern Mediterranean and Anatolia, where it was cultivated for food beginning by 2000 BCE at the latest.

[12] Many varieties of kale and cabbage are grown mainly for ornamental leaves that are brilliant white, red, pink, lavender, blue, or violet in the interior of the rosette.

In a 100 g (3+1⁄2 oz) serving, raw kale provides 207 kilojoules (49 kilocalories) of food energy and a large amount of vitamin K at 3.7 times the Daily Value (DV).

Kale is a good source (10–19% DV) of thiamin, riboflavin, pantothenic acid, vitamin E, and several dietary minerals, including iron, calcium, magnesium, potassium, and phosphorus.

[20] Boiling kale decreases the level of glucosinate compounds, whereas steaming, microwaving, or stir frying does not cause significant loss.

[25] In the Netherlands, a traditional winter dish called "boerenkoolstamppot" is a mix of curly kale and mashed potatoes, sometimes with fried bacon, and served with rookworst ("smoked sausage").

[29] A traditional Portuguese soup, caldo verde, combines pureed potatoes, very finely sliced kale, olive oil and salt.

In Scotland, kale provided such a base for a traditional diet that the word in some Scots dialects is synonymous with food.

In the United Kingdom, the cultivation of kale (and other vegetables) was encouraged during World War II via the Dig for Victory campaign.

For most of the 20th century, kale was primarily used in the U.S. for decorative purposes; it became more popular as an edible vegetable in the 1990s due to its nutritional value.

[36] In Cuthbertson's book Autumn in Kyle and the charm of Cunninghame, he states that Kilmaurs in East Ayrshire was famous for its kale, which was an important foodstuff.