Kale

For other uses, see Kale (disambiguation).

Kale
Curly kale, one of the many varieties of kale
Species	Brassica oleracea
Cultivar group	Acephala Group
Origin	Unknown, but before the Middle Ages
Cultivar group members	Many; see text.

Kale (English: IPA: /keɪl/) or leaf cabbage refers to certain vegetable cultivars of the plant species Brassica oleracea. A kale plant has green or purple leaves and the central leaves do not form a head (as with headed cabbages). Kales are considered to be closer to wild cabbage than most domesticated forms of Brassica oleracea.

Children collecting leaves of red Russian kale (Brassica napus L. subsp. napus var. pabularia (DC.) Alef.) in a family vegetable garden

Etymology

Kale bears semblance to "kail", a variant of "cawul" (from Scotland and northern England) for various cabbages.

History

Until the end of the Middle Ages, kale was one of the most common green vegetables in Europe. Curly-leaved varieties of cabbage already existed along with flat-leaved varieties in Greece in the fourth century BC. It was also used as medicinal food source. Disocorides wrote that it could be used to treat bowel ailments. These forms, which were referred to by the Romans as Sabellian kale, are considered to be the ancestors of modern kales.

Kale was brought to North America by the colonists in the 16th century. Later, Russian kale was introduced into Canada, and then into the United States, by Russian traders in the 19th century.

During World War II, the cultivation of kale in the U.K. was encouraged by the Dig for Victory campaign. The vegetable was easy to grow and provided important nutrients missing from a diet because of rationing.

Description

A traditional New Years Danish dish: boiled ham, glazed potatoes and stewed kale

Some varieties can reach a height of six or seven feet, while others are compact, symmetrical and of good quality for eating. Many, however, are coarse and indigestible. Most kales are annuals or biennials. Kale seeds resemble those of cabbage in size, form, and color.

Cultivars

One may differentiate between kale varieties according to the low, intermediate, or high length of the stem, along with the variety of leaf types. The leaf colours range from light green to green, to dark green and violet-green, to violet-brown.

Classification by leaf type:

• Curly-leaf (Scots kale, blue curled kale)
• Bumpy-leaf (black cabbage, better known by its Italian translation 'cavolo nero', and also known as Tuscan Cabbage, Tuscan Kale, lacinato and dinosaur kale)
• Plain-leaf
• Rape kale
• Leaf and spear (a cross between curly-leaf and plain-leaf)

Because kale can grow well into winter, one variety of rape kale is called "hungry gap" after the period in winter in traditional agriculture when little else could be harvested. An extra-tall variety is known as Jersey kale or cow cabbage. Kai-lan or Chinese kale is a cultivar often used in Chinese cuisine, but in English it is occasionally just called "kale". In Portugal, the bumpy-leaved kale is mostly called "couve galega" (Galician kale or Portuguese Cabbage), although in some regions other names may be used.

Ornamental kale in white and lavender

Cultivation

Kale is usually an annual plant grown from seed with a wide range of germination temperatures. It is hardy and thrives in wintertime, and can survive in temperatures as low as -15 degrees. Kale can become sweeter after a heavy frost.

Ornamental kale

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. Ornamental kale is as edible as any other variety, but potentially not as palatable. Kale leaves are increasingly used as an ingredient for vegetable bouquets and wedding bouquets.

Nutritional value

Kale, raw

Nutritional value per 100 g (3.5 oz)
Energy	207 kJ (49 kcal)
Carbohydrates	8.8 g
Sugars	2.3 g
Dietary fiber	3.6 g
Fat	0.9 g
Protein	4.3 g
Vitamins and minerals Vitamins Quantity %DV† Vitamin A equiv. lutein zeaxanthin 56% 500 μg 8198 μg Thiamine (B1) 9% 0.11 mg Riboflavin (B2) 10% 0.13 mg Niacin (B3) 6% 1.0 mg Pantothenic acid (B5) 18% 0.9 mg Vitamin B6 16% 0.27 mg Folate (B9) 35% 141 μg Choline 0% 0.8 mg Vitamin C 133% 120 mg Vitamin E 10% 1.54 mg Vitamin K 588% 705 μg Minerals Quantity %DV† Calcium 12% 150 mg Iron 8% 1.5 mg Magnesium 11% 47 mg Manganese 29% 0.66 mg Phosphorus 7% 92 mg Potassium 16% 491 mg Selenium 2% 0.9 μg Sodium 2% 38 mg Zinc 5% 0.6 mg
Other constituents	Quantity
Water	84.0 g
Full Link to USDA Database entry
†Percentages estimated using US recommendations for adults, except for potassium, which is estimated based on expert recommendation from the National Academies.

Kale, cooked, boiled, drained, without salt

Nutritional value per 100 g (3.5 oz)
Energy	117 kJ (28 kcal)
Carbohydrates	5.63 g
Sugars	1.25 g
Dietary fiber	2 g
Fat	0.4 g
Protein	1.9 g
Vitamins and minerals Vitamins Quantity %DV† Vitamin A equiv. lutein zeaxanthin 76% 681 μg 18246 μg Thiamine (B1) 4% 0.053 mg Riboflavin (B2) 5% 0.07 mg Niacin (B3) 3% 0.5 mg Pantothenic acid (B5) 1% 0.05 mg Vitamin B6 8% 0.138 mg Folate (B9) 3% 13 μg Choline 0% 0.4 mg Vitamin C 46% 41 mg Vitamin E 6% 0.85 mg Vitamin K 681% 817 μg Minerals Quantity %DV† Calcium 6% 72 mg Iron 5% 0.9 mg Magnesium 4% 18 mg Manganese 18% 0.416 mg Phosphorus 2% 28 mg Potassium 8% 228 mg Selenium 2% 0.9 μg Sodium 1% 23 mg Zinc 2% 0.24 mg
Other constituents	Quantity
Water	91.2 g
Full Link to USDA Database entry
†Percentages estimated using US recommendations for adults, except for potassium, which is estimated based on expert recommendation from the National Academies.

Raw kale is composed of 84% water, 9% carbohydrates, 4% protein, and 1% fat (table). In a 100 gram serving, raw kale provides 49 calories. Like collards, it contains a large amount of vitamin K: several times the Daily Value (DV). It is a rich source (20% or more of the DV) of vitamin A, vitamin C, vitamin B6, folate, and manganese (see table "Kale, raw"). Kale is a good source (10–19% DV) of thiamin, riboflavin, pantothenic acid, vitamin E and several dietary minerals, including iron, calcium, potassium, and phosphorus (see table "Kale, raw").

Boiling raw kale diminishes most of these nutrients except for vitamin K (see table "Kale, cooked [...]").

Phytochemicals and health

Kale is a source of the carotenoids lutein and zeaxanthin (tables).

As with broccoli and other cruciferous vegetables, kale contains glucosinolate compounds such as glucoraphanin, which contributes to the formation of sulforaphane, a compound under preliminary research for its potential to affect human health. Boiling kale decreases the level of glucosinate compounds, whereas steaming, microwaving or stir frying does not result in significant loss.

Culinary uses

Tender kale greens can provide an intense addition to salads, particularly when combined with other strongly flavoured ingredients like dry-roasted peanuts, soy sauce–roasted almonds, red capsicum flakes, or sesame-based salad dressings.

Flavored "kale chips" have been produced as a potato chip substitute.

Regional uses

In the Southern United States, kale is often served braised, either alone or mixed with greens like collard, mustard, or turnip. It is also used in salads. In Brazil, it is a side dish for a common stew called feijoada. Various kale types are eaten throughout southeastern Africa, where they are typically boiled with coconut milk and ground peanuts and served with rice or boiled cornmeal.

Europe

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").

In Italy, cavolo nero is an ingredient of the Tuscan soup ribollita. Kale (cavolo nero) is part of many dishes, such as cassoeula (pork stew) and polenta (corn porridge).

A whole culture around kale has developed in northern Germany, especially around the towns of Bremen, Oldenburg, Osnabrück and Hannover and the region of Dithmarschen. There, most social clubs of any kind will have a Grünkohlessen or Kohlfahrt ("kale tour") sometime between October and February, visiting a country inn to consume kale stew, pinkel sausage, kassler, mettwurst and schnapps. Most communities in the area have a yearly kale festival which includes naming a "kale king" (or queen).

Curly kale is used in Denmark and southwestern Sweden (Scania, Halland and Blekinge) to make (grøn-)langkål (Danish) or långkål (Swedish), an obligatory dish on the julbord in the region, and is commonly served together with the Christmas ham (Sweden). The leaves of the kale are separated from the stem, and then boiled with stock. The result is drained and pressed to remove the remaining liquid. The kale can now be frozen for up to 6–8 months if needed. To make langkål, finely chop the (defrosted) kale and fry it with cream, pepper, and syrup (or sugar) for sweetening. In Sweden, it is also commonly eaten as a soup, with a base of ham broth and the addition of onion and pork sausages.

A traditional Portuguese soup, caldo verde, combines pureed potatoes, diced kale, olive oil and salt. Additional ingredients can include broth and sliced, cooked spicy sausage.

In Montenegro and Croatia, collards and kale, locally known as rashtan, is a favourite vegetable. It is particularly popular in the winter, cooked with smoked mutton (kastradina) and potatoes.

In Scotland, kale provided such a base for a traditional diet that the word in Scots dialectics is synonymous with food. To be "off one's kail" is to feel too ill to eat.

In Ireland, kale is mixed with mashed potatoes to make the traditional dish colcannon. It is popular on Halloween, when it may be served with sausages.

In Turkey, especially in the eastern Black Sea region, kale soup (karalahana çorbası), kale sarma, kale kavurma (sauté), and kale turşu are common dishes.

Asia

A variety of kale, called kai-lan or Gai lan, is a common vegetable in China, Taiwan, and Vietnam, where it may be consumed with beef dishes. In Japan and South Korea, kale juice, known in Japan as aojiru (AKA "green juice"), is used as a dietary supplement.

In literature

The Kailyard school of Scottish writers, which included J. M. Barrie (creator of Peter Pan), consisted of authors who wrote about traditional rural Scottish life (kailyard = kale field). 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. A story is told in which a neighbouring village offered to pay a generous price for some kale seeds, an offer too good to turn down. The locals agreed, but a gentle roasting on a shovel over a coal fire ensured that the seeds never germinated.

== Symbolic associations ==
In the United States, eating kale (and eating healthy in general) is associated with an urban lifestyle and with liberal-leaning, Democrat voters. Ham and beans are associated with conservative Republicans.

Gallery

• 
  Curly-leaf kale
• 
  Red Russian kale
• 
  Making kale chips in Illinois

See also

• Bowen's Kale
• Crambe maritima – sea kale
• Kalettes

External links

• Marrow-Stem Kale – Plants for a Future database
• PROTAbase on Brassica oleracea (leaf cabbage)
• Turow, Eve (16 December 2015). "The Strange Mystery of Who Made Kale Famous...and Why". mindbodygreen. Retrieved 29 March 2017.