Kale (), also called leaf cabbage, belongs to a group of cabbage (''

Brassica oleracea ''Brassica oleracea'', also known as wild cabbage in its uncultivated form, is a plant of the family Brassicaceae. The species originated from feral populations of related plants in the Eastern Mediterranean, where it was most likely first cultiv ...

'')

cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...

s primarily grown for their edible leaves; it has also been used as an

ornamental plant Ornamental plants or ''garden plants'' are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars th ...

. Its multiple different cultivars vary quite a bit in appearance; the leaves can be bumpy, curly, or flat, and the color ranges from purple to green.

Description

Kale plants have green or purple leaves, and the central leaves do not form a head, as with

headed cabbage Cabbage, comprising several cultivars of ''Brassica oleracea'', is a leafy green, red (purple), or white (pale green) biennial plant grown as an annual vegetable crop for its dense-leaved heads. It is descended from the wild cabbage ( ''B.&nbs ...

. The stems can be white or red, and can be tough even when cooked.

Etymology

The name ''kale'' originates from Northern

Middle English Middle English (abbreviated to ME) is a form of the English language that was spoken after the Norman Conquest of 1066, until the late 15th century. The English language underwent distinct variations and developments following the Old English pe ...

''cale'' (compare Scots ''kail'' and German ''Kohl'') for various

cabbage Cabbage, comprising several cultivars of '' Brassica oleracea'', is a leafy green, red (purple), or white (pale green) biennial plant grown as an annual vegetable crop for its dense-leaved heads. It is descended from the wild cabbage ( ''B.& ...

s. The ultimate origin is

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''caulis'' 'cabbage'.

Cultivation

Derived from

wild mustard Brassicaceae () or (the older but equally valid) Cruciferae () is a medium-sized and economically important family of flowering plants commonly known as the mustards, the crucifers, or the cabbage family. Most are herbaceous plants, while some ar ...

, kale is considered to be closer to wild cabbage than most domesticated forms of ''B. oleracea''. Kale is usually a

biennial plant A biennial plant is a flowering plant that, generally in a temperate climate, takes two years to complete its biological life cycle. Background In its first year, the biennial plant undergoes primary growth, during which its vegetative structur ...

grown from seed with a wide range of

germination Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, ...

temperatures. It is

hardy Hardy may refer to: People * Hardy (surname) * Hardy (given name) * Hardy (singer), American singer-songwriter Places Antarctica * Mount Hardy, Enderby Land * Hardy Cove, Greenwich Island * Hardy Rocks, Biscoe Islands Australia * Hardy, ...

and thrives in wintertime, and can survive in temperatures as low as .Derek B. Munro Kale can become sweeter after a heavy frost.

History

Kale originated in the eastern Mediterranean and

Anatolia Anatolia (), also known as Asia Minor, is a peninsula in West Asia that makes up the majority of the land area of Turkey. It is the westernmost protrusion of Asia and is geographically bounded by the Mediterranean Sea to the south, the Aegean ...

, where it was cultivated for food beginning by 2000 BCE at the latest. Curly-leaved varieties of cabbage already existed along with flat-leaved varieties in

Greece Greece, officially the Hellenic Republic, is a country in Southeast Europe. Located on the southern tip of the Balkan peninsula, it shares land borders with Albania to the northwest, North Macedonia and Bulgaria to the north, and Turkey to th ...

in the 4th century BC. These forms, which were referred to by the

Romans Roman or Romans most often refers to: *Rome, the capital city of Italy *Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of Roman civilization *Epistle to the Romans, shortened to Romans, a letter w ...

as Sabellian kale, are considered to be the ancestors of modern kales. The earliest record of cabbages in western Europe is of hard-heading cabbage in the 13th century. Records in 14th-century England distinguish between hard-heading cabbage and loose-leaf kale. Russian traders introduced Russian kale into Canada and then into the United States in the 19th century.

USDA The United States Department of Agriculture (USDA) is an United States federal executive departments, executive department of the Federal government of the United States, United States federal government that aims to meet the needs of commerc ...

botanist

David Fairchild David Grandison Fairchild (April 7, 1869 – August 6, 1954) was an American botanist and plant explorer. Fairchild was responsible for the introduction of more than 200,000 exotic plants and varieties of established crops into the United Stat ...

is credited with introducing kale (and many other crops) to Americans, having brought it back from

Croatia Croatia, officially the Republic of Croatia, is a country in Central Europe, Central and Southeast Europe, on the coast of the Adriatic Sea. It borders Slovenia to the northwest, Hungary to the northeast, Serbia to the east, Bosnia and Herze ...

, although Fairchild himself disliked cabbages, including kale. At the time, kale was widely grown in Croatia mostly because it was easy to grow and inexpensive, and could

desalinate Desalination is a process that removes mineral components from saline water. More generally, desalination is the removal of salts and minerals from a substance. One example is soil desalination. This is important for agriculture. It is possible ...

soil.

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, dark green, violet-green, and 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 Lacinato kale, also known as Tuscan kale, Italian kale, dinosaur kale, kale, flat back kale, palm tree kale, black Tuscan palm, or, in Italian and often in English, , is a variety of kale from the Acephala group of cultivars ''Brassica oleracea ...

, Tuscan Kale, lacinato and dinosaur kale) * Sparkly-leaf (shiny and glossy) * Plain-leaf (flat-leaf types like red Russian and white Russian kale) * Leaf and spear, or feathery-type leaf (a cross between curly- and plain-leaf) *Ornamental (less palatable and tougher leaves) Ornamental Kale

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 The Jersey cabbage (''Brassica oleracea longata'') is a variety of cabbage native to the Channel Islands that grows to a great height and was formerly commonly used there as livestock fodder and for making walking sticks. It is also known as Jer ...

'' or ''cow cabbage''. ''

Kai-lan Gai lan, kai-lan, Chinese broccoli, or Chinese kale (''Brassica oleracea'' var. ''alboglabra'') is a leafy vegetable with thick, flat, glossy blue-green leaves with thick stems, and florets similar to (but much smaller than) broccoli. A ''B ...

'' or ''Chinese kale'' is a cultivar often used in Chinese cuisine. In Portugal, the bumpy-leaved kale is mostly called "couve galega" (Galician kale or Portuguese Cabbage).

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. The different types of ornamental kale are peacock kale, coral prince, kamone coral queen, color up kale, and chidori kale. ''Ornamental kale'' is as edible as any other variety, but potentially not as

palatable Palatability (or palatableness) is the hedonic reward (which is pleasure of taste in this case) provided by foods or drinks that are agreeable to the "palate", which often varies relative to the homeostatic satisfaction of nutritional and/or wat ...

. Kale leaves are increasingly used as an ingredient for vegetable bouquets and wedding bouquets.

Uses

Nutrition

Raw kale is 84% water, 9%

carbohydrate A carbohydrate () is a biomolecule composed of carbon (C), hydrogen (H), and oxygen (O) atoms. The typical hydrogen-to-oxygen atomic ratio is 2:1, analogous to that of water, and is represented by the empirical formula (where ''m'' and ''n'' ...

s, 4%

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

, and 1%

fat In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food. The term often refers specif ...

(table). In a serving, raw kale provides of

food energy Food energy is chemical energy that animals and humans derive from food to sustain their metabolism and muscular activity. Most animals derive most of their energy from aerobic respiration, namely combining the carbohydrates, fats, and protein ...

and 3.7 times the

Daily Value In the U.S. and Canada, the Reference Daily Intake (RDI) is used in nutrition labeling on food and dietary supplement products to indicate the daily intake level of a nutrient that is considered to be sufficient to meet the requirements of 97� ...

(DV) of

vitamin K Vitamin K is a family of structurally similar, fat-soluble vitamers found in foods and marketed as dietary supplements. The human body requires vitamin K for post-translational modification, post-synthesis modification of certain proteins ...

. It is a rich source (20% or more of the DV) of

vitamin A Vitamin A is a fat-soluble vitamin that is an essential nutrient. The term "vitamin A" encompasses a group of chemically related organic compounds that includes retinol, retinyl esters, and several provitamin (precursor) carotenoids, most not ...

vitamin C Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits, berries and vegetables. It is also a generic prescription medication and in some countries is sold as a non-prescription di ...

folate Folate, also known as vitamin B9 and folacin, is one of the B vitamins. Manufactured folic acid, which is converted into folate by the body, is used as a dietary supplement and in food fortification as it is more stable during processing and ...

, and

manganese Manganese is a chemical element; it has Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese was first isolated in the 1770s. It is a transition m ...

(see table "Kale, raw"). Kale is a good source (10–19% DV) of

riboflavin Riboflavin, also known as vitamin B2, is a vitamin found in food and sold as a dietary supplement. It is essential to the formation of two major coenzymes, flavin mononucleotide and flavin adenine dinucleotide. These coenzymes are involved in ...

pantothenic acid Pantothenic acid (vitamin B5) is a B vitamin and an essential nutrient. All animals need pantothenic acid in order to synthesize coenzyme A (CoA), which is essential for cellular energy production and for the synthesis and degradation of prote ...

vitamin B6 Vitamin B6 is one of the B vitamins, and is an essential nutrient for humans. The term essential nutrient refers to a group of six chemically similar compounds, i.e., "vitamers", which can be interconverted in biological systems. Its active f ...

vitamin E Vitamin E is a group of eight compounds related in molecular structure that includes four tocopherols and four tocotrienols. The tocopherols function as fat-soluble antioxidants which may help protect cell membranes from reactive oxygen speci ...

, and several

dietary minerals In the context of nutrition, a mineral is a chemical element. Some "minerals" are essential for life, but most are not. ''Minerals'' are one of the four groups of essential nutrients; the others are vitamins, essential fatty acids, and essen ...

, including

calcium Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to it ...

magnesium Magnesium is a chemical element; it has Symbol (chemistry), symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 ...

, and

potassium Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...

(table). Boiling raw kale diminishes most of these nutrients, while values for vitamins A, C, and K and manganese remain substantial (table for cooked kale).

Phytochemicals

Kale is a source of the

carotenoid Carotenoids () are yellow, orange, and red organic pigments that are produced by plants and algae, as well as several bacteria, archaea, and fungi. Carotenoids give the characteristic color to pumpkins, carrots, parsnips, corn, tomatoes, cana ...

lutein Lutein (;"Lutein"

zeaxanthin Zeaxanthin is one of the most common carotenoids in nature, and is used in the xanthophyll cycle. Synthesized in plants and some micro-organisms, it is the pigment that gives paprika (made from bell peppers), corn, saffron, goji ( wolfberries) ...

. As with

broccoli Broccoli (''Brassica oleracea'' var. ''italica'') is an edible green plant in the Brassicaceae, cabbage family (family Brassicaceae, genus ''Brassica'') whose large Pseudanthium, flowering head, plant stem, stalk and small associated leafy gre ...

and other

cruciferous vegetable Cruciferous vegetables are vegetables of the family Brassicaceae (also called Cruciferae) with many genera, species, and cultivars being raised for food production such as cauliflower, cabbage, kale, garden cress, bok choy, broccoli, Brussels sp ...

s, kale contains

glucosinolate Glucosinolates are natural components of many pungent plants such as mustard, cabbage, and horseradish. The pungency of those plants is due to mustard oils produced from glucosinolates when the plant material is chewed, cut, or otherwise damaged. ...

compounds, such as

glucoraphanin Glucoraphanin is a glucosinolate found in broccoli, mustard and other cruciferous vegetables. Glucoraphanin is converted to sulforaphane by the enzyme myrosinase. In plants, sulforaphane deters insect predators and acts as a selective antibioti ...

, which contributes to the formation of

sulforaphane Sulforaphane (sometimes sulphoraphane in British English) is a phytochemical within the isothiocyanate group of organosulfur compounds. It is produced when the enzyme myrosinase transforms glucoraphanin, a glucosinolate, into sulforaphane up ...

, a compound under preliminary research for its potential to affect human health beneficially. Boiling kale decreases the level of glucosinate compounds, whereas

steaming Steaming is a method of cooking using steam. This is often done with a food steamer, a kitchen appliance made specifically to cook food with steam, but food can also be steamed in a wok. In the American Southwest, steam pits used for cooking ha ...

microwaving A microwave oven, or simply microwave, is an electric oven that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range. This induces polar molecules in the food to rotate and produce thermal energy ( ...

, or

stir frying Stir frying ( zh, c= 炒, p=chǎo, w=ch'ao3, cy=cháau) is a cooking technique in which ingredients are fried in a small amount of very hot oil while being stirred or tossed in a wok. The technique originated in China and in recent centuries ...

does not cause significant loss. Kale is high in

oxalic acid Oxalic acid is an organic acid with the systematic name ethanedioic acid and chemical formula , also written as or or . It is the simplest dicarboxylic acid. It is a white crystalline solid that forms a colorless solution in water. Its name i ...

, the levels of which can be reduced by cooking. Kale contains high levels of

polyphenols Polyphenols () are a large family of naturally occurring phenols. They are abundant in plants and structurally diverse. Polyphenols include phenolic acids, flavonoids, tannic acid, and ellagitannin, some of which have been used historically as ...

, such as

ferulic acid Ferulic acid is a hydroxycinnamic acid derivative and a phenolic compound. It is an organic compound with the formula (CH3O)HOC6H3CH=CHCO2H. The name is derived from the genus '' Ferula'', referring to the giant fennel ('' Ferula communis''). Cl ...

, with levels varying due to environmental and genetic factors.

Culinary

Snack product

Kale chips have been produced as a

potato chip Potato chips (North American English and Australian English; often just chip) or crisp (British English and Hiberno-English) are thin slices of potato (or a thin deposit of potato paste) that has been deep frying, deep fried, baking, baked, ...

substitute.

Regional uses

= Europe

= In the

Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...

, a traditional winter dish called " boerenkoolstamppot" is a mix of curly kale and mashed potatoes, sometimes with fried bacon, and served with

rookworst Rookworst (; smoked sausage) or Gelderse rookworst is a type of Dutch sausage in which ground meat is mixed with spices and salt and stuffed into a casing. Having the shape of a Bologna sausage, it is common in the Netherlands and is also exp ...

("smoked sausage"). In

Northern Germany Northern Germany (, ) is a linguistic, geographic, socio-cultural and historic region in the northern part of Germany which includes the coastal states of Schleswig-Holstein, Mecklenburg-Vorpommern and Lower Saxony and the two city-states Hambur ...

, there is a winter tradition known as " Kohlfahrt" ("kale trip"), where a group of people will go on a hike through the woods during the day before gathering at an inn or private residence where kale is served, usually with bacon and

Kohlwurst Kohlwurst, Lungenwurst or Lungwurst is a simple, fresh, strongly smoked sausage (''Rohwurst'') made of lights (lungs), pork and fat, which is mostly eaten cooked with kale (cabbage) dishes, such as '' Knieperkohl''. (The word "Kohl" in German r ...

("kale sausage"). Kale is considered a Northern German staple and

comfort food Comfort food is food that provides a nostalgic or sentimental value to someone and may be characterized by its high caloric nature associated with childhood or home cooking. The nostalgia may be specific to an individual or it may apply to a ...

. In Italy,

cavolo nero Lacinato kale, also known as Tuscan kale, Italian kale, dinosaur kale, kale, flat back kale, palm tree kale, black Tuscan palm, or, in Italian and often in English, , is a variety of kale from the Acephala group of cultivars ''Brassica oleracea ...

kale is an ingredient of the Tuscan soup

ribollita ''Ribollita'' () is a Tuscan bread soup, panade, porridge, or potage made with bread and vegetables, often from leftovers. There are many variations, but the usual ingredients include leftover bread, cannellini beans, lacinato kale, cabbage a ...

. A traditional Portuguese soup, ''

caldo verde ''Caldo verde'' (, Portuguese language, Portuguese for "green broth") is a popular soup in Portuguese cuisine. The basic traditional ingredients for ''caldo verde'' are Julienning, julienned collard greens or ''couve-galega'' (essentially a t ...

'', combines pureed potatoes, very finely sliced kale,

olive oil Olive oil is a vegetable oil obtained by pressing whole olives (the fruit of ''Olea europaea'', a traditional Tree fruit, tree crop of the Mediterranean Basin) and extracting the oil. It is commonly used in cooking for frying foods, as a cond ...

and salt. Additional ingredients can include broth and sliced, cooked spicy

sausage A sausage is a type of meat product usually made from ground meat—often pork, beef, or poultry—along with salt, spices and other flavourings. Other ingredients, such as grains or breadcrumbs, may be included as fillers or extenders. ...

. In Scotland, kale provided such a base for a traditional diet that the word in some

Scots dialects Scots may refer to: People and cultures * Scots language * Scottish people * Scoti, a Latin name for the Gaels Other uses * SCOTS, abbreviation for Royal Regiment of Scotland * Scottish Corpus of Texts and Speech (SCOTS), a linguistic resource * ...

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 Colcannon ( ) is a traditional Irish dish of mashed potatoes with cabbage. It is a popular dish on Saint Patrick's Day and on the feast day of St. Brigid. Description Colcannon is most commonly made with only four ingredients: potatoes, butte ...

''. It is popular on

Halloween Halloween, or Hallowe'en (less commonly known as Allhalloween, All Hallows' Eve, or All Saints' Eve), is a celebration geography of Halloween, observed in many countries on 31 October, the eve of the Western Christianity, Western Christian f ...

, when it may be served with sausages. In the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

, the cultivation of kale (and other vegetables) was encouraged during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

via the

Dig for Victory Digging, also referred to as excavation, is the process of using some implement such as claws, hands, manual tools or heavy equipment, to remove material from a solid surface, usually soil, sand or rock on the surface of Earth. Digging is actua ...

campaign. The vegetable was easy to grow and provided important nutrients missing from a diet because of

rationing Rationing is the controlled distribution (marketing), distribution of scarcity, scarce resources, goods, services, or an artificial restriction of demand. Rationing controls the size of the ration, which is one's allowed portion of the resourc ...

= Asia

= In Sri Lanka, it is known as ''kola gova'' or ela gova. It is cultivated for edible use. A dish called 'kale mallung' is served almost everywhere on the island, along with rice.

= United States

= For most of the 20th century, kale was primarily used in the U.S. for decorative purposes; it became more commonly consumed starting in the 1990s, mainly due to its nutritional value. It is now one of the most popular greens in the U.S., and is commonly used in salads and

green smoothies A smoothie is a beverage made by puréeing ingredients in a blender. A smoothie commonly has a liquid base, such as fruit juice or milk, yogurt or ice cream. Other ingredients may be added, including fruits, vegetables, non-dairy milk, crushed ...

In culture

The ''Kailyard'' school of Scottish writers, which included

J. M. Barrie Sir James Matthew Barrie, 1st Baronet, (; 9 May 1860 19 June 1937) was a Scottish novelist and playwright, best remembered as the creator of Peter Pan. He was born and educated in Scotland and then moved to London, where he wrote several succe ...

(creator of

Peter Pan Peter Pan is a fictional character created by Scottish novelist and playwright J. M. Barrie. A free-spirited and mischievous young boy who can fly and never grows up, Peter Pan spends his never-ending childhood having adventures on the mythical ...

), 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 Kilmaurs () is a village in East Ayrshire, Scotland which lies just outside of the largest settlement in East Ayrshire, Kilmarnock. It lies on the Carmel Water, southwest of Glasgow. Population recorded for the village in the 2001 Census record ...

East Ayrshire East Ayrshire (; ) is one of 32 unitary council areas of Scotland. It shares borders with Dumfries and Galloway, East Renfrewshire, North Ayrshire, South Ayrshire and South Lanarkshire. The headquarters of the council are located on London Roa ...

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 the seeds never germinated.Cuthbertson, David Cuningham (1945). ''Autumn in Kyle and the Charm of Cunninghame''. London: Jenkins. Page 186

Gallery

File:Kale-Bundle.jpg, Curly-leaf kale File:CSA-Red-Russian-Kale.jpg, Red Russian kale File:20170526-AMS-LSC-0326 (34137217614).jpg,

Tuscan kale Lacinato kale, also known as Tuscan kale, Italian kale, dinosaur kale, kale, flat back kale, palm tree kale, black Tuscan palm, or, in Italian and often in English, , is a variety of kale from the Acephala group of cultivars ''Brassica oleracea ...

File:Making kale chips in Lockport, Illinois.jpg, Making kale chips File:Kogt skinke brunede kartofler grønlangkål.jpg, A traditional New Years Danish dish: boiled ham, glazed potatoes and stewed kale File:Vegan Stack at Two Mountains (cropped).jpg, A kale-based dish with other vegetables and

sourdough bread Sourdough is a type of bread that uses the fermentation, fermentation by naturally occurring yeast and lactobacillaceae, lactobacillus bacteria to raise the dough. In addition to leavening the bread, the fermentation process produces lactic acid ...

, served at a restaurant in Australia

References

External links

Marrow-Stem Kale
– Plants for a Future database
PROTAbase on ''Brassica oleracea'' (leaf cabbage)
{{Authority control Brassica oleracea Leaf vegetables