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The potato is a starchy, tuberous crop from the perennial nightshade Solanum tuberosum. The word "potato" may refer either to the plant itself or to the edible tuber.[2] In the Andes, where the species is indigenous, there are some other closely related cultivated potato species. Potatoes were introduced outside the Andes region approximately four centuries ago,[3] and have since become an integral part of much of the world's food supply. It is the world's fourth-largest food crop, following maize, wheat, and rice.[4] The green leaves and green skins of tubers exposed to the light are toxic.
Wild potato species can be found throughout the Americas from the United States to southern Chile.[5] The potato was originally believed to have been domesticated independently in multiple locations,[6] but later genetic testing of the wide variety of cultivars and wild species proved a single origin for potatoes in the area of present-day southern Peru and extreme northwestern Bolivia (from a species in the Solanum brevicaule complex), where they were domesticated approximately 7,000–10,000 years ago.[7][8][9] Following centuries of selective breeding, there are now over a thousand different types of potatoes.[8] Over 99% of the presently cultivated potatoes worldwide descended from varieties that originated in the lowlands of south-central Chile, which have displaced formerly popular varieties from the Andes.[10][11]
However, the local importance of the potato is variable and changing rapidly. It remains an essential crop in Europe (especially eastern and central Europe), where per capita production is still the highest in the world, but the most rapid expansion over the past few decades has occurred in southern and eastern Asia. As of 2007 China led the world in potato production, and nearly a third of the world's potatoes were harvested in China and India.[12]
Etymology
The English word potato comes from Spanish patata (the name used in Spain). The Spanish Royal Academy says the Spanish word is a compound of the Taíno batata and the Quechua papa (potato).[13] The name potato originally referred to a type of sweet potato although the two plants are not closely related; in many of the chronicles detailing agriculture and plants, no distinction is made between the two.[14] The 16th-century English herbalist John Gerard used the terms "bastard potatoes" and "Virginia potatoes" for this species, and referred to sweet potatoes as "common potatoes".[15] Potatoes are occasionally referred to as "Irish potatoes" or "white potatoes" in the United States, to distinguish them from sweet potatoes.[15]
The name spud for a small potato comes from the digging of soil (or a hole) prior to the planting of potatoes. The word has an unknown origin and was originally (c. 1440) used as a term for a short knife or dagger, probably related to Dutch spyd or the Latin "spad-" a word root meaning "sword"; cf. Spanish "espada", English "spade" and "spadroon". The word spud traces back to the 16th century. It subsequently transferred over to a variety of digging tools. Around 1845, the name transferred to the tuber itself.[16] The origin of the word "spud" has erroneously been attributed to a 19th-century activist group dedicated to keeping the potato out of Britain, calling itself The Society for the Prevention of an Unwholesome Diet (S.P.U.D.).[16] It was Mario Pei's 1949 The Story of Language that can be blamed for the word's false origin. Pei writes, "the potato, for its part, was in disrepute some centuries ago. Some Englishmen who did not fancy potatoes formed a Society for the Prevention of Unwholesome Diet. The initials of the main words in this title gave rise to spud." Like most other pre-20th century acronymic origins, this is false.[16]
There are about 5,000 potato varieties worldwide. Three thousand of them are found in the Andes alone, mainly in Peru, Bolivia, Ecuador, Chile, and Colombia. They belong to eight or nine species, depending on the taxonomic school. Apart from the 5,000 cultivated varieties, there are about 200 wild species and subspecies, many of which can be cross-bred with cultivated varieties. Cross-breeding has been done repeatedly to transfer resistances to certain pests and diseases from the gene pool of wild species to the gene pool of cultivated potato species. Genetically modified varieties have met public resistance in the United States and in the European Union.[19][20]
The major species grown worldwide is Solanum tuberosum (a tetraploid with 48 chromosomes), and modern varieties of this species are the most widely cultivated. There are also four diploid species (with 24 chromosomes): S. stenotomum, S. phureja, S. goniocalyx, and S. ajanhuiri. There are two triploid species (with 36 chromosomes): S. chaucha and S. juzepczukii. There is one pentaploid cultivated species (with 60 chromosomes): S. curtilobum. There are two major subspecies of Solanum tuberosum: andigena, or Andean; and tuberosum, or Chilean.[21] The Andean potato is adapted to the short-day conditions prevalent in the mountainous equatorial and tropical regions where it originated; the Chilean potato, however, native to the Chiloé Archipelago, is adapted to the long-day conditions prevalent in the higher latitude region of southern Chile.[22]
The International Potato Center, based in Lima, Peru, holds an ISO-accredited collection of potato germplasm.[23] The international Potato Genome Sequencing Consortium announced in 2009 that they had achieved a draft sequence of the potato genome.[24] The potato genome contains 12 chromosomes and 860 million base pairs, making it a medium-sized plant genome.[25] More than 99 percent of all current varieties of potatoes currently grown are direct descendants of a subspecies that once grew in the lowlands of south-central Chile.[26] Nonetheless, genetic testing of the wide variety of cultivars and wild species affirms that all potato subspecies derive from a single origin in the area of present-day southern Peru and extreme northwestern Bolivia (from a species in the Solanum brevicaule complex).[7][8][9]
Most modern potatoes grown in North America arrived through European settlement and not independently from the South American sources; however, at least one wild potato species, Solanum fendleri, is found as far north as Texas and is used in breeding for resistance to a nematode species that attacks cultivated potatoes. A secondary center of genetic variability of the potato is Mexico, where important wild species that have been used extensively in modern breeding are found, such as the hexaploid Solanum demissum, as a source of resistance to the devastating late blight disease.[27] Another relative native to this region, Solanum bulbocastanum, has been used to genetically engineer the potato to resist potato blight.[28]
Potatoes yield abundantly with little effort, and adapt readily to diverse climates as long as the climate is cool and moist enough for the plants to gather sufficient water from the soil to form the starchy tubers. Potatoes do not keep very well in storage and are vulnerable to molds that feed on the stored tubers and quickly turn them rotten, however: crops such as grain can be stored for several years with a low risk of rot. The yield of Calories per acre (about 9.2 million) is higher than that of maize (7.5 million), rice (7.4 million), wheat (3 million), or soybean (2.8 million).[29]
The potato was first domesticated in the region of modern-day southern Peru and extreme northwestern Bolivia[7] between 8000 and 5000 BC.[8] It has since spread around the world and become a staple crop in many countries.
The earliest archaeologically verified potato tuber remains have been found at the coastal site of Ancon (central Peru), dating to 2500 BC.[30][31]
According to conservative estimates, the introduction of the potato was responsible for a quarter of the growth in Old World population and urbanization between 1700 and 1900.[32] Following the Spanish conquest of the Inca Empire, the Spanish introduced the potato to Europe in the second half of the 16th century. The staple was subsequently conveyed by European mariners to territories and ports throughout the world. The potato was slow to be adopted by distrustful European farmers, but soon enough it became an important food staple and field crop that played a major role in the European 19th century population boom.[9] However, lack of genetic diversity, due to the very limited number of varieties initially introduced, left the crop vulnerable to disease. In 1845, a plant disease known as late blight, caused by the fungus-like oomycete Phytophthora infestans, spread rapidly through the poorer communities of western Ireland, resulting in the crop failures that led to the Great Irish Famine.[27] Thousands of varieties still persist in the Andes however, where over 100 cultivars might be found in a single valley, and a dozen or more might be maintained by a single agricultural household.[33]
The Food and Agriculture Organization of the United Nations reports that the world production of potatoes in 2013 was about 368 million tonnes.[34] Just over two thirds of the global production is eaten directly by humans with the rest being fed to animals or used to produce starch. This means that the annual diet of an average global citizen in the first decade of the 21st century included about 33 kg (or 73 lb) of potato.[4] However, the local importance of potato is extremely variable and rapidly changing. It remains an essential crop in Europe (especially eastern and central Europe), where per capita production is still the highest in the world, but the most rapid expansion over the past few decades has occurred in southern and eastern Asia. As of 2007, China led the world in potato production, and nearly a third of the world's potatoes were harvested in China and India.[12] The geographic shift of potato production has been away from wealthier countries toward lower-income areas of the world, although the degree of this trend is ambiguous.[35]
In 2008, several international organizations highlighted the potato's role in world food production, in the face of developing economic problems. They cited its potential derived from its status as a cheap and plentiful crop that grows in a wide variety of climates and locales.[36]
International Year of the Potato
Main article: International Year of the Potato
Due to perishability, only about 5% of the world's potato crop is traded internationally; its minimal presence in world financial markets contributed to its stable pricing during the 2007–2008 world food price crisis.[37][38] Thus, the United Nations officially declared 2008 as the International Year of the Potato,[39] to raise its profile in developing nations, calling the crop a "hidden treasure".[40] This followed the International Rice Year in 2004.
Nutrition
Potato, raw, with skin
Nutritional value per 100 g (3.5 oz)
Energy 321 kJ (77 kcal)
Carbohydrates
17.47 g
Starch 15.44 g
Dietary fiber 2.2 g
Fat
0.1 g
Protein
2 g
Vitamins
Thiamine (B1) (7%) 0.08 mg
Riboflavin (B2) (3%) 0.03 mg
Niacin (B3) (7%) 1.05 mg
Pantothenic acid (B5) (6%) 0.296 mg
Vitamin B6 (23%) 0.295 mg
Folate (B9) (4%) 16 μg
Vitamin C (24%) 19.7 mg
Vitamin E (0%) 0.01 mg
Vitamin K (2%) 1.9 μg
Minerals
Calcium (1%) 12 mg
Iron (6%) 0.78 mg
Magnesium (6%) 23 mg
Manganese (7%) 0.153 mg
Phosphorus (8%) 57 mg
Potassium (9%) 421 mg
Sodium (0%) 6 mg
Zinc (3%) 0.29 mg
Other constituents
Water 75 g
Link to USDA Database entry
Units
μg = micrograms • mg = milligrams
IU = International units
Percentages are roughly approximated using US recommendations for adults.
Source: USDA Nutrient Database
The potato contains vitamins and minerals, as well as an assortment of phytochemicals, such as carotenoids and natural phenols. Chlorogenic acid constitutes up to 90% of the potato tuber natural phenols. Others found in potatoes are 4-O-caffeoylquinic acid (crypto-chlorogenic acid), 5-O-caffeoylquinic (neo-chlorogenic acid), 3,4-dicaffeoylquinic and 3,5-dicaffeoylquinic acids.[41] A medium-size 150 g (5.3 oz) potato with the skin provides 27 mg of vitamin C (45% of the Daily Value (DV)), 620 mg of potassium (18% of DV), 0.2 mg vitamin B6 (10% of DV) and trace amounts of thiamin, riboflavin, folate, niacin, magnesium, phosphorus, iron, and zinc.
The potato is best known for its carbohydrate content (approximately 26 grams in a medium potato). The predominant form of this carbohydrate is starch. A small but significant portion of this starch is resistant to digestion by enzymes in the stomach and small intestine, and so reaches the large intestine essentially intact. This resistant starch is considered to have similar physiological effects and health benefits as fiber: It provides bulk, offers protection against colon cancer, improves glucose tolerance and insulin sensitivity, lowers plasma cholesterol and triglyceride concentrations, increases satiety, and possibly even reduces fat storage.[42][43][44] The amount of resistant starch in potatoes depends much on preparation methods. Cooking and then cooling potatoes significantly increases resistant starch. For example, cooked potato starch contains about 7% resistant starch, which increases to about 13% upon cooling.[45]
The storage and cooking method used can significantly affect the nutrient availability of the potato.[46][47]
Potatoes are often broadly classified as high on the glycemic index (GI) and so are often excluded from the diets of individuals trying to follow a low-GI diet. In fact, the GI of potatoes can vary considerably depending on type (such as red, russet, white, or King Edward), origin (where it was grown), preparation methods (i.e., cooking method, whether it is eaten hot or cold, whether it is mashed or cubed or consumed whole, etc.), and with what it is consumed (i.e., the addition of various high-fat or high-protein toppings).[48]
In the UK, potatoes are not considered by the NHS as counting towards the recommended daily five portions of fruit and vegetables.[49]
Comparison to other major staple foods
The following table shows the nutrient content of potato and other major staple foods, each in respective raw form. Staple foods are not commonly eaten raw and are usually sprouted or cooked before eating. In sprouted and cooked form, the relative nutritional and anti-nutritional contents of each of these grains may be different from the values reported in this table.
The potato is a starchy, tuberous crop from the perennial nightshade Solanum tuberosum. The word "potato" may refer either to the plant itself or to the edible tuber.[2] In the Andes, where the species is indigenous, there are some other closely related cultivated potato species. Potatoes were introduced outside the Andes region approximately four centuries ago,[3] and have since become an integral part of much of the world's food supply. It is the world's fourth-largest food crop, following maize, wheat, and rice.[4] The green leaves and green skins of tubers exposed to the light are toxic.
Wild potato species can be found throughout the Americas from the United States to southern Chile.[5] The potato was originally believed to have been domesticated independently in multiple locations,[6] but later genetic testing of the wide variety of cultivars and wild species proved a single origin for potatoes in the area of present-day southern Peru and extreme northwestern Bolivia (from a species in the Solanum brevicaule complex), where they were domesticated approximately 7,000–10,000 years ago.[7][8][9] Following centuries of selective breeding, there are now over a thousand different types of potatoes.[8] Over 99% of the presently cultivated potatoes worldwide descended from varieties that originated in the lowlands of south-central Chile, which have displaced formerly popular varieties from the Andes.[10][11]
However, the local importance of the potato is variable and changing rapidly. It remains an essential crop in Europe (especially eastern and central Europe), where per capita production is still the highest in the world, but the most rapid expansion over the past few decades has occurred in southern and eastern Asia. As of 2007 China led the world in potato production, and nearly a third of the world's potatoes were harvested in China and India.[12]
Etymology
The English word potato comes from Spanish patata (the name used in Spain). The Spanish Royal Academy says the Spanish word is a compound of the Taíno batata and the Quechua papa (potato).[13] The name potato originally referred to a type of sweet potato although the two plants are not closely related; in many of the chronicles detailing agriculture and plants, no distinction is made between the two.[14] The 16th-century English herbalist John Gerard used the terms "bastard potatoes" and "Virginia potatoes" for this species, and referred to sweet potatoes as "common potatoes".[15] Potatoes are occasionally referred to as "Irish potatoes" or "white potatoes" in the United States, to distinguish them from sweet potatoes.[15]
The name spud for a small potato comes from the digging of soil (or a hole) prior to the planting of potatoes. The word has an unknown origin and was originally (c. 1440) used as a term for a short knife or dagger, probably related to Dutch spyd or the Latin "spad-" a word root meaning "sword"; cf. Spanish "espada", English "spade" and "spadroon". The word spud traces back to the 16th century. It subsequently transferred over to a variety of digging tools. Around 1845, the name transferred to the tuber itself.[16] The origin of the word "spud" has erroneously been attributed to a 19th-century activist group dedicated to keeping the potato out of Britain, calling itself The Society for the Prevention of an Unwholesome Diet (S.P.U.D.).[16] It was Mario Pei's 1949 The Story of Language that can be blamed for the word's false origin. Pei writes, "the potato, for its part, was in disrepute some centuries ago. Some Englishmen who did not fancy potatoes formed a Society for the Prevention of Unwholesome Diet. The initials of the main words in this title gave rise to spud." Like most other pre-20th century acronymic origins, this is false.[16]
There are about 5,000 potato varieties worldwide. Three thousand of them are found in the Andes alone, mainly in Peru, Bolivia, Ecuador, Chile, and Colombia. They belong to eight or nine species, depending on the taxonomic school. Apart from the 5,000 cultivated varieties, there are about 200 wild species and subspecies, many of which can be cross-bred with cultivated varieties. Cross-breeding has been done repeatedly to transfer resistances to certain pests and diseases from the gene pool of wild species to the gene pool of cultivated potato species. Genetically modified varieties have met public resistance in the United States and in the European Union.[19][20]
The major species grown worldwide is Solanum tuberosum (a tetraploid with 48 chromosomes), and modern varieties of this species are the most widely cultivated. There are also four diploid species (with 24 chromosomes): S. stenotomum, S. phureja, S. goniocalyx, and S. ajanhuiri. There are two triploid species (with 36 chromosomes): S. chaucha and S. juzepczukii. There is one pentaploid cultivated species (with 60 chromosomes): S. curtilobum. There are two major subspecies of Solanum tuberosum: andigena, or Andean; and tuberosum, or Chilean.[21] The Andean potato is adapted to the short-day conditions prevalent in the mountainous equatorial and tropical regions where it originated; the Chilean potato, however, native to the Chiloé Archipelago, is adapted to the long-day conditions prevalent in the higher latitude region of southern Chile.[22]
The International Potato Center, based in Lima, Peru, holds an ISO-accredited collection of potato germplasm.[23] The international Potato Genome Sequencing Consortium announced in 2009 that they had achieved a draft sequence of the potato genome.[24] The potato genome contains 12 chromosomes and 860 million base pairs, making it a medium-sized plant genome.[25] More than 99 percent of all current varieties of potatoes currently grown are direct descendants of a subspecies that once grew in the lowlands of south-central Chile.[26] Nonetheless, genetic testing of the wide variety of cultivars and wild species affirms that all potato subspecies derive from a single origin in the area of present-day southern Peru and extreme northwestern Bolivia (from a species in the Solanum brevicaule complex).[7][8][9]
Most modern potatoes grown in North America arrived through European settlement and not independently from the South American sources; however, at least one wild potato species, Solanum fendleri, is found as far north as Texas and is used in breeding for resistance to a nematode species that attacks cultivated potatoes. A secondary center of genetic variability of the potato is Mexico, where important wild species that have been used extensively in modern breeding are found, such as the hexaploid Solanum demissum, as a source of resistance to the devastating late blight disease.[27] Another relative native to this region, Solanum bulbocastanum, has been used to genetically engineer the potato to resist potato blight.[28]
Potatoes yield abundantly with little effort, and adapt readily to diverse climates as long as the climate is cool and moist enough for the plants to gather sufficient water from the soil to form the starchy tubers. Potatoes do not keep very well in storage and are vulnerable to molds that feed on the stored tubers and quickly turn them rotten, however: crops such as grain can be stored for several years with a low risk of rot. The yield of Calories per acre (about 9.2 million) is higher than that of maize (7.5 million), rice (7.4 million), wheat (3 million), or soybean (2.8 million).[29]
The potato was first domesticated in the region of modern-day southern Peru and extreme northwestern Bolivia[7] between 8000 and 5000 BC.[8] It has since spread around the world and become a staple crop in many countries.
The earliest archaeologically verified potato tuber remains have been found at the coastal site of Ancon (central Peru), dating to 2500 BC.[30][31]
According to conservative estimates, the introduction of the potato was responsible for a quarter of the growth in Old World population and urbanization between 1700 and 1900.[32] Following the Spanish conquest of the Inca Empire, the Spanish introduced the potato to Europe in the second half of the 16th century. The staple was subsequently conveyed by European mariners to territories and ports throughout the world. The potato was slow to be adopted by distrustful European farmers, but soon enough it became an important food staple and field crop that played a major role in the European 19th century population boom.[9] However, lack of genetic diversity, due to the very limited number of varieties initially introduced, left the crop vulnerable to disease. In 1845, a plant disease known as late blight, caused by the fungus-like oomycete Phytophthora infestans, spread rapidly through the poorer communities of western Ireland, resulting in the crop failures that led to the Great Irish Famine.[27] Thousands of varieties still persist in the Andes however, where over 100 cultivars might be found in a single valley, and a dozen or more might be maintained by a single agricultural household.[33]
The Food and Agriculture Organization of the United Nations reports that the world production of potatoes in 2013 was about 368 million tonnes.[34] Just over two thirds of the global production is eaten directly by humans with the rest being fed to animals or used to produce starch. This means that the annual diet of an average global citizen in the first decade of the 21st century included about 33 kg (or 73 lb) of potato.[4] However, the local importance of potato is extremely variable and rapidly changing. It remains an essential crop in Europe (especially eastern and central Europe), where per capita production is still the highest in the world, but the most rapid expansion over the past few decades has occurred in southern and eastern Asia. As of 2007, China led the world in potato production, and nearly a third of the world's potatoes were harvested in China and India.[12] The geographic shift of potato production has been away from wealthier countries toward lower-income areas of the world, although the degree of this trend is ambiguous.[35]
In 2008, several international organizations highlighted the potato's role in world food production, in the face of developing economic problems. They cited its potential derived from its status as a cheap and plentiful crop that grows in a wide variety of climates and locales.[36]
International Year of the Potato
Main article: International Year of the Potato
Due to perishability, only about 5% of the world's potato crop is traded internationally; its minimal presence in world financial markets contributed to its stable pricing during the 2007–2008 world food price crisis.[37][38] Thus, the United Nations officially declared 2008 as the International Year of the Potato,[39] to raise its profile in developing nations, calling the crop a "hidden treasure".[40] This followed the International Rice Year in 2004.
Nutrition
Potato, raw, with skin
Nutritional value per 100 g (3.5 oz)
Energy 321 kJ (77 kcal)
Carbohydrates
17.47 g
Starch 15.44 g
Dietary fiber 2.2 g
Fat
0.1 g
Protein
2 g
Vitamins
Thiamine (B1) (7%) 0.08 mg
Riboflavin (B2) (3%) 0.03 mg
Niacin (B3) (7%) 1.05 mg
Pantothenic acid (B5) (6%) 0.296 mg
Vitamin B6 (23%) 0.295 mg
Folate (B9) (4%) 16 μg
Vitamin C (24%) 19.7 mg
Vitamin E (0%) 0.01 mg
Vitamin K (2%) 1.9 μg
Minerals
Calcium (1%) 12 mg
Iron (6%) 0.78 mg
Magnesium (6%) 23 mg
Manganese (7%) 0.153 mg
Phosphorus (8%) 57 mg
Potassium (9%) 421 mg
Sodium (0%) 6 mg
Zinc (3%) 0.29 mg
Other constituents
Water 75 g
Link to USDA Database entry
Units
μg = micrograms • mg = milligrams
IU = International units
Percentages are roughly approximated using US recommendations for adults.
Source: USDA Nutrient Database
The potato contains vitamins and minerals, as well as an assortment of phytochemicals, such as carotenoids and natural phenols. Chlorogenic acid constitutes up to 90% of the potato tuber natural phenols. Others found in potatoes are 4-O-caffeoylquinic acid (crypto-chlorogenic acid), 5-O-caffeoylquinic (neo-chlorogenic acid), 3,4-dicaffeoylquinic and 3,5-dicaffeoylquinic acids.[41] A medium-size 150 g (5.3 oz) potato with the skin provides 27 mg of vitamin C (45% of the Daily Value (DV)), 620 mg of potassium (18% of DV), 0.2 mg vitamin B6 (10% of DV) and trace amounts of thiamin, riboflavin, folate, niacin, magnesium, phosphorus, iron, and zinc.
The potato is best known for its carbohydrate content (approximately 26 grams in a medium potato). The predominant form of this carbohydrate is starch. A small but significant portion of this starch is resistant to digestion by enzymes in the stomach and small intestine, and so reaches the large intestine essentially intact. This resistant starch is considered to have similar physiological effects and health benefits as fiber: It provides bulk, offers protection against colon cancer, improves glucose tolerance and insulin sensitivity, lowers plasma cholesterol and triglyceride concentrations, increases satiety, and possibly even reduces fat storage.[42][43][44] The amount of resistant starch in potatoes depends much on preparation methods. Cooking and then cooling potatoes significantly increases resistant starch. For example, cooked potato starch contains about 7% resistant starch, which increases to about 13% upon cooling.[45]
The storage and cooking method used can significantly affect the nutrient availability of the potato.[46][47]
Potatoes are often broadly classified as high on the glycemic index (GI) and so are often excluded from the diets of individuals trying to follow a low-GI diet. In fact, the GI of potatoes can vary considerably depending on type (such as red, russet, white, or King Edward), origin (where it was grown), preparation methods (i.e., cooking method, whether it is eaten hot or cold, whether it is mashed or cubed or consumed whole, etc.), and with what it is consumed (i.e., the addition of various high-fat or high-protein toppings).[48]
In the UK, potatoes are not considered by the NHS as counting towards the recommended daily five portions of fruit and vegetables.[49]
Comparison to other major staple foods
The following table shows the nutrient content of potato and other major staple foods, each in respective raw form. Staple foods are not commonly eaten raw and are usually sprouted or cooked before eating. In sprouted and cooked form, the relative nutritional and anti-nutritional contents of each of these grains may be different from the values reported in this table.
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