In botany, a nut is a fruit from a tree (or shrub) consisting of a hard or tough nutshell protecting a kernel which is usually edible. The shell is indehiscent, meaning it does not open to release the seed.[1] Most seeds come from fruits that naturally free themselves from the shell, but this is not the case in nuts such as hazelnuts, chestnuts, and acorns, which have hard shell walls and originate from a compound ovary.
Common usage of the term is less restrictive, which refers to any hard-walled, edible kernel as a nut.[2] This original usage is preserved in a culinary sense, where many dry seeds are called "nuts" and come from indehiscent fruits. Almonds, cashews, pistachios, and Brazil nuts,[3] are examples of "tree nuts" that are not true nuts. Peanuts are a unique case, and grow underground from a legume.
A seed is the mature fertilised ovule of a plant; it consists of three parts, the embryo which will develop into a new plant, stored food for the embryo, and a protective seed coat. Botanically, a nut is a fruit with a woody pericarp developing from a syncarpous gynoecium. Nuts may be contained in an involucre, a cup-shaped structure formed from the flower bracts. The involucre may be scaly, spiny, leafy or tubular, depending on the species of nut.[5] Most nuts come from the pistils with inferior ovaries (see flower) and all are indehiscent (not opening at maturity). True nuts are produced, for example, by some plant families of the orderFagales. These include beech (Fagus), chestnut (Castanea), oak (Quercus), stone-oak (Lithocarpus) and tanoak (Notholithocarpus) in the family Fagaceae, as well as hazel, filbert (Corylus) and hornbeam (Carpinus) in the family Betulaceae.
Also widely known as nuts are dry drupes, which include pecans (Carya illinoensis), almonds (Prunus amygdalus), macadamia (Macadamia integrifolia), candlenut (Aleurites moluccanus) and the water caltrop (Trapa bicornis). A drupe is an indehiscent fruit that has an outer fleshy part consisting of the exocarp, or skin, and mesocarp, or flesh, which surround a single pit or stone, the endocarp with a seed (kernel) inside. In a dry drupe, the outer parts dry up and the remaining husk is part of the ovary wall or pericarp, and the hard inner wall surrounding the seed represents the inner part of the pericarp.[5]
A small nut may be called a "nutlet" (formerly called a nucule,[6] a term otherwise referring to the oogonium of stoneworts[7]). In botany, the term "nutlet" can be used to describe a pyrena or pyrene, which is a seed covered by a stony layer, such as the kernel of a drupe.[8] Walnuts and hickories (Juglandaceae) have fruits that are difficult to classify. They are considered to be nuts under some definitions but are also referred to as drupaceous nuts.[citation needed]
In common use, a "tree nut" is, as the name implies, any nut coming from a tree. This most often comes up regarding food allergies; a person may be allergic specifically to peanuts (which are not tree nuts but legumes), whereas others may be allergic to the wider range of nuts that grow on trees.
In the 21st century, about a dozen species constitute most of the worldwide production of nuts, shown in the table below for major commercial nuts.[9][10]
The fruit is a drupe, consisting of an outer hull and a hard shell, the endocarp, containing a single seed.[5] Almonds are sold shelled or unshelled. Blanched almonds are almonds with the shells removed that have been treated with hot water to soften the seed coat, which is then removed.
World production of unshelled almonds in 2019 was 3.5million tonnes, and the largest producing countries were the United States, Spain, Iran, Turkey and Morocco.[9]
Native to temperate regions of the Northern Hemisphere, and was at one time a staple crop in some regions.
It is a true nut and grows in a spiny, cup-shaped involucre formed from the calyx.[5]
World production in 2019 was 2.4million tonnes, and the main producing countries were China, Turkey, South Korea, Portugal, Italy, Greece and Spain.[9]
The fruit is a dry drupe, with both the coconut flesh and the coconut water developing from the endosperm, being surrounded by the fibrous husk.[5]
Has the largest world production of any nuts, with a global figure of 62.51million tonnes in 2019, with Indonesia, the Philippines and India being the largest producers.[9]
Native to temperate regions of the Northern Hemisphere.
The fruit is a true nut and grows in a leafy or tubular involucre formed from the calyx.[5]
In 2019, world production of hazelnuts in shells was 1.1million tonnes, predominantly grown in Turkey, with other notable producing countries being Italy, Azerbaijan, the United States, Chile and China.[9]
Native to Central Asia, where it is a desert tree.
The fruit is a drupe, containing a single elongated seed in a hard, cream-coloured shell, which abruptly splits open when ripe.[5]
World production in 2019 totalled 0.9million tonnes, the main producing countries being Iran and the United States, with lesser quantities coming from China and Turkey.[9]
J. regia originated in south eastern Europe, western/central Asia, and J. nigra originated in the eastern United States.
The fruit is a pseudo-drupe with a green, semi-fleshy husk.[5]
In 2019, world production of walnuts in shells was 4.5million tonnes, predominantly grown in China, with other notable producing countries being the United States and Iran.[9]
Toxicity
Nuts used for food are a common source of food allergens.[4] Reactions can range from mild symptoms to severe ones, a condition known as anaphylaxis, which can be life-threatening. The reaction is due to the release of histamine by the body in response to an allergen in the nuts, causing skin and other possible reactions.[14] Many experts suggest that a person with an allergy to peanuts should avoid eating tree nuts, and vice versa.[4][15]
Nuts contain the diverse nutrients that are needed for the growth of a new plant.[4] Composition varies, but they tend to have a low water and carbohydrate content, with high levels of fats, protein, dietary minerals, and vitamins.[4] The digestibility of the protein at about 90% is slightly lower than that of meat and fish, but can be improved by chewing thoroughly.[16] The fats are largely unsaturated and nuts are a source of essential omega-3 fatty acids.[4][17] As part of a healthy human diet, long-term consumption of diverse nutrients in nuts may contribute to a lower risk of cardiovascular diseases, reduced levels of blood cholesterol, and lower all-cause mortality.[4] For vegetarians and vegans, nuts provide many of the essential nutrients which may be in short supply in other plant foods.[16]
Nuts supply nutrients for humans and wildlife.[4] Because nuts generally have a high oil content, they are a significant energy source.[4] Many seeds are edible by humans and used in cooking, eaten raw, sprouted, or roasted as a snack food, ground to make nut butters, or pressed for oil that is used in cooking and cosmetics.[4] Regular nut consumption of more than 5 ounces (140g) per week may benefit weight control and contribute to lowering body weight in humans.[4]
Constituents
Nuts are the source of energy and nutrients for the new plant. They contain a relatively large quantity of calories, essential unsaturated and monounsaturated fats including linoleic acid and linolenic acid, vitamins, and essential amino acids.[4] Many nuts are good sources of vitamin E, vitamin B2, folate, fiber, and essential minerals, such as magnesium, phosphorus, potassium, copper, and selenium.[4][18]
This table lists the percentage of various nutrients in four unroasted seeds.
Name
Protein
Total fat
Saturated fat
Polyunsaturated fat
Monounsaturated fat
Carbohydrate
Almonds
21.26
50.64
3.881
12.214
32.155
28.1
Walnuts
15.23
65.21
6.126
47.174
8.933
19.56
Peanuts
23.68
49.66
6.893
15.694
24.64
26.66
Pistachio
20.61
44.44
5.44
13.455
23.319
34.95
Research
Nuts are under preliminary research to assess whether their consumption is associated with lower risk for some diseases, such as cardiovascular diseases and cancer.[4][19] A 2014 review indicated that consuming one or more servings of nuts or peanut butter per day was associated with lower risk of ischemic heart disease, overall cardiovascular disease, stroke in women, and all-cause mortality.[20] A 2022 umbrella review confirmed these findings and found a 22% reduction in all-cause mortality.[21]
The almond is a species of tree from the genus Prunus. Along with the peach, it is classified in the subgenus Amygdalus, distinguished from the other subgenera by corrugations on the shell (endocarp) surrounding the seed.
In botany, a fruit is the seed-bearing structure in flowering plants (angiosperms) that is formed from the ovary after flowering.
The pistachio, a member of the cashew family, is a small to medium tree originating in Persia. The tree produces seeds that are widely consumed as food. The word can be countable or uncountable, meaning its plural is with or without an 's'.
The peanut, also known as the groundnut, goober (US), goober pea, pindar (US) or monkey nut (UK), is a legume crop grown mainly for its edible seeds. It is widely grown in the tropics and subtropics by small and large commercial producers, both as grain legume and as an oil crop. Atypically among legumes, peanut pods develop underground leading botanist Carl Linnaeus to name peanuts hypogaea, which means "under the earth".
Cashew is the common name of a tropical evergreen tree Anacardium occidentale, in the family Anacardiaceae. It is native to South America and is the source of the cashew nut and the cashew apple, an accessory fruit. The tree can grow as tall as 14 metres, but the dwarf cultivars, growing up to 6 m (20 ft), prove more profitable, with earlier maturity and greater yields. The cashew nut is edible and is eaten on its own as a snack, used in recipes, or processed into cashew cheese or cashew butter. The nut is often simply called a 'cashew'.
Macadamia is a genus of four species of trees in the flowering plant family Proteaceae. They are indigenous to Australia, native to northeastern New South Wales and central and southeastern Queensland specifically. Two species of the genus are commercially important for their fruit, the macadamia nut. Global production in 2015 was 160,000 tonnes. Other names include Queensland nut, bush nut, maroochi nut, bauple nut and, in the US, they are also known as Hawaii nut. It was an important source of bushfood for the Aboriginal peoples.
Pine nuts, also called piñón, pinoli, or pignoli, are the edible seeds of pines. According to the Food and Agriculture Organization, only 29 species provide edible nuts, while 20 are traded locally or internationally owing to their seed size being large enough to be worth harvesting; in other pines, the seeds are also edible but are too small to be of notable value as human food. The biggest producers of pine nuts are China, Russia, North Korea, Pakistan and Afghanistan.
Corylus avellana, the common hazel, is a species of flowering plant in the birch family Betulaceae. The shrubs usually grow 3–8 metres tall. The nut is round, in contrast to the longer filbert nut. Common hazel is native to Europe and Western Asia.
A food allergy is an abnormal immune response to food. The symptoms of the allergic reaction may range from mild to severe. They may include itchiness, swelling of the tongue, vomiting, diarrhea, hives, trouble breathing, or low blood pressure. This typically occurs within minutes to several hours of exposure. When the symptoms are severe, it is known as anaphylaxis. A food intolerance and food poisoning are separate conditions, not due to an immune response.
A healthy diet is a diet that maintains or improves overall health. A healthy diet provides the body with essential nutrition: fluid, macronutrients such as protein, micronutrients such as vitamins, and adequate fibre and food energy.
A whole grain is a grain of any cereal and pseudocereal that contains the endosperm, germ, and bran, in contrast to refined grains, which retain only the endosperm.
Canarium ovatum, the pili, is a species of tropical tree belonging to the genus Canarium. It is one of approximately 600 species in the family Burseraceae. C. ovatum are native to the Philippines. They are commercially cultivated in the Philippines for their edible nuts and is believed to be indigenous to that country. The fruit and tree are often vulgarized with the umbrella term of "Java almond" which mixes multiple species of the same genus, Canarium.
A milk substitute is any substance that resembles milk and can be used in the same ways as milk. Such substances may be variously known as non-dairy beverage, nut milk, grain milk, legume milk, mock milk and alternative milk.
A tree nut allergy is a hypersensitivity to dietary substances from tree nuts and edible tree seeds causing an overreaction of the immune system which may lead to severe physical symptoms. Tree nuts include almonds, Brazil nuts, cashews, chestnuts, filberts/hazelnuts, macadamia nuts, pecans, pistachios, shea nuts and walnuts.
Macadamia tetraphylla is a tree species in the family Proteaceae native to Australia. Common names include macadamia nut, bauple nut, prickly macadamia, Queensland nut, rough-shelled bush nut and rough-shelled Queensland nut.
Fruits are the mature ovary or ovaries of one or more flowers. They are found in three main anatomical categories: aggregate fruits, multiple fruits, and simple fruits.
Simple fruits are the result of the ripening-to-fruit of a simple or compound ovary in a single flower with a single pistil. In contrast, a single flower with numerous pistils typically produces an aggregate fruit; and the merging of several flowers, or a 'multiple' of flowers, results in a 'multiple' fruit. A simple fruit is further classified as either dry or fleshy.
Canarium indicum, known as galip nut, is a mainly dioecious tree native in eastern Melanesia. It is usually found in rainforests, secondary forests, old garden areas, around villages and settlements. It is also used as a shade tree, as a windbreak and in agroforestry. Canarium is important in the world food system as it can be used as a food and timber source, in traditional medicine, intercropping and agroforestry.
↑ Alasalvar, Cesarettin; Shahidi, Fereidoon (17 December 2008). Tree Nuts: Composition, Phytochemicals, and Health Effects (Nutraceutical Science and Technology). CRC. p.143. ISBN978-0-8493-3735-2.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 "Nuts". Micronutrient Information Center, Linus Pauling Institute, Oregon State University, Corvallis, OR. 1 September 2018. Archived from the original on 28 March 2019. Retrieved 28 March 2019.
1 2 Jaffa, Myer Edward (1908). Nuts and Their Uses as Food. U.S. Government Printing Office. pp.14–18. Archived from the original on 27 April 2023. Retrieved 10 July 2021.
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