Brazil nut

Template:Short description Template:Distinguish Template:Use mdy dates Template:Speciesbox Brazil nut (Bertholletia excelsa) refers to a South American tree in the family Lecythidaceae as well as the tree's commercially-harvested edible seeds.<ref name="mori">Template:Cite web</ref> It is one of the largest and longest-lived trees in the Amazon rainforest. The fruit and its nutshell – containing the edible nut – are relatively large and weigh as much as Template:Cvt in total. As food, Brazil nuts are notable for diverse content of micronutrients, especially a high amount of selenium. The wood of the Brazil nut tree is prized for its quality in carpentry, flooring, and heavy construction.

In 2023, Brazil and Bolivia combined produced 91% of the world total of Brazil nuts.

Common names

In Portuguese-speaking countries, like Brazil, they are variously called "Template:Lang"<ref name=":p0">Template:Cite web - Folder Embrapa</ref><ref name=":p1">COSTA, J. R. (et al.).Uma das espécies nativas mais valiosas da floresta amazônica de terra firme é a castanha-do-brasil ou castanha-da-amazônia (Bertholletia excelsa), - Acta Amazônica vol. 39(4) 2009: 843 - 850</ref> (meaning "chestnut from Brazil" in Portuguese), "Template:Lang" (meaning "chestnut from Pará" in Portuguese), castanha-da-amazônia,<ref>Template:Cite book</ref> castanha-do-acre,<ref>Template:Cite web - Ministério do Meio Ambiente. Rio de Janeiro, 2003. p. 50.</ref> "Template:Lang" (meaning "Amazonian nut" in Portuguese), noz boliviana, tocari (probably of Carib origin<ref>Template:Cite journal</ref>), and tururi (from Tupi turu'ri<ref>Ferreira, A. B. H. (1986). Novo Dicionário da Língua Portuguesa (2nd edition). Rio de Janeiro: Nova Fronteira. p. 1729</ref>).<ref name=mori/>

In various Spanish-speaking countries of South America, Brazil nuts are called Template:Lang, Template:Lang, or Template:Lang.<ref name=mori/><ref>Template:Cite report</ref>

In North America, as early as 1896, Brazil nuts were sometimes known by the slang term "nigger toes",<ref>Template:Cite book</ref><ref>Template:Cite journal</ref><ref>Template:Cite dictionary</ref> a vulgarity that fell out of use after the racial slur became more socially unacceptable.<ref>Template:Cite magazine</ref><ref>Template:Cite journal</ref>

Description

File:Brazil Nut - Project Gutenberg eBook 11662.jpg

Depiction of the Brazil nut in Scientific American Supplement, No. 598, June 18, 1887

The Brazil nut is a large tree, reaching Template:Convert tall,<ref name="henn">Template:Cite web</ref> with a trunk Template:Cvt in diameter, making it among the largest of trees in the Amazon rainforest. It may live for 500 years or more, and can often reach a thousand years of age.<ref>Template:Cite web</ref> The stem is straight and commonly without branches for well over half the tree's height, with a large, emergent crown of long branches above the surrounding canopy of other trees.

The bark is grayish and smooth. The leaves are dry-season deciduous, alternate, simple, entire or crenate, oblong, Template:Convert long, and Template:Cvt broad. The flowers are small, greenish-white, in panicles Template:Cvt long; each flower has a two-parted, deciduous calyx, six unequal cream-colored petals, and numerous stamens united into a broad, hood-shaped mass.Template:Citation needed

Reproduction

Brazil nut trees produce fruit almost exclusively in pristine forests, as disturbed forests lack the large-bodied bees of the genera Bombus, Centris, Epicharis, Eulaema, and Xylocopa, which are the only ones capable of pollinating the tree's flowers, with different bee genera being the primary pollinators in different areas, and different times of year.<ref name=Nelson1985>Template:Cite journal</ref><ref name=Moritz1984>Template:Cite book</ref><ref>Template:Cite journal</ref> Brazil nuts have been harvested from plantations, but production is low and is currently not economically viable.<ref name=mori/><ref name=henn/><ref>Template:Cite web</ref>

File:Brazil nut DSC05477.JPG

A freshly cut Brazil nut fruit

The fruit takes 14 months to mature after pollination of the flowers. The fruit itself is a large capsule Template:Cvt in diameter, resembling a coconut endocarp in size and weighing up to Template:Cvt. It has a hard, woody shell Template:Cvt thick, which contains eight to 24 wedge-shaped seeds Template:Cvt long (the "Brazil nuts") packed like the segments of an orange, but not limited to one whorl of segments. Up to three whorls can be stacked onto each other, with the polar ends of the segments of the middle whorl nestling into the upper and lower whorls (see illustration above).

The capsule contains a small hole at one end, which enables large rodents like the agouti to gnaw it open.<ref name="seeds">Template:Cite journal</ref> They then eat some of the seeds inside while burying others for later use; some of these are able to germinate into new Brazil nut trees.<ref name=seeds/> Most of the seeds are "planted" by the agoutis in caches during wet season,<ref name=seeds/> and the young saplings may have to wait years, in a state of dormancy, for a tree to fall and sunlight to reach it, when it starts growing again.

Taxonomy

The Brazil nut family, the Lecythidaceae, is in the order Ericales, as are other well-known plants such as blueberries, cranberries, sapote, gutta-percha, tea, phlox, and persimmons. The tree is the only species in the monotypic genus Bertholletia,<ref name="mori" /> named after French chemist Claude Louis Berthollet.<ref>Template:Cite book</ref>

Distribution and habitat

The Brazil nut is native to the Guianas, Venezuela, Brazil, eastern Colombia, eastern Peru, and eastern Bolivia. It occurs as scattered trees in large forests on the banks of the Amazon River, Rio Negro, Tapajós, and the Orinoco. The fruit is heavy and rigid; when the fruits fall, they pose a serious threat to vehicles and potential for traumatic brain injury of people passing under the tree.<ref name="ideta">Template:Cite journal</ref>

Ecology

Capuchin monkeys have been reported to open Brazil nuts using a stone as an anvil.Template:Cn

Production

Brazil nut production
Template:Small

Template:BRA	35,351
Template:BOL	33,650
Template:PER	6,909
World	75,910
Template:Small<ref name="faostat">Template:Cite web</ref>

In 2023, world production of Brazil nuts (in shells) was 75,910 tonnes, most of which derive from wild harvests in tropical forests, especially the Amazon regions of Brazil and Bolivia which together produced 91% of the total (table).

Environmental effects of harvesting

Since most of the production for international trade is harvested in the wild,<ref name="evans">Template:Cite web</ref><ref name="kivner">Template:Cite news</ref> the business arrangement has been advanced as a model for generating income from a tropical forest without destroying it.<ref name=evans/> The nuts are most often gathered by migrant workers known as castañeros (in Spanish) or castanheiros (in Portuguese).<ref name=evans/> Logging is a significant threat to the sustainability of the Brazil nut-harvesting industry.<ref name=evans/><ref name= kivner/>

Analysis of tree ages in areas that are harvested shows that moderate and intense gathering takes so many seeds that not enough are left to replace older trees as they die.<ref name=kivner/> Sites with light gathering activities had many young trees, while sites with intense gathering practices had nearly none.<ref>Template:Cite journal</ref>

Toxicity

File:Brazil nuts.jpg

Brazil nuts after shell removal

Brazil nuts are susceptible to contamination by aflatoxins, produced by fungi, once they fall to the ground.<ref>Template:Cite web</ref> Aflatoxins can cause liver damage, including possible cancer, if consumed.<ref name="eujournal" /> Aflatoxin levels have been found in Brazil nuts during inspections that were far higher than the limits set by the EU.<ref>Template:Cite web</ref> However, mechanical sorting and drying was found to eliminate 98% of aflatoxins; a 2003 EU ban on importation<ref name="eujournal" /> was rescinded after new tolerance levels were set.

The nuts may contain traces of radium, a radioactive element, with a kilogram of nuts containing an activity between Template:Convert. This level of radium is small, although higher than in other common foods. According to Oak Ridge Associated Universities, elevated levels of radium in the soil does not directly cause the concentration of radium, but "the very extensive root system of the tree" can concentrate naturally occurring radioactive material, when present in the soil.<ref>Template:Cite web</ref> Radium can be concentrated in nuts only if it is present in the soil.<ref>Template:Cite web</ref>

Brazil nuts also contain barium, a metal with a chemical behavior quite similar to radium.<ref>Template:Cite web</ref> While barium can have toxic side effects when ingested (weakness, vomiting, diarrhea, etc.)<ref>Template:Cite web</ref> the amount present in Brazil nuts is too small to have noticeable health effects.

European Union import regulation

In 2003, the European Union imposed strict regulations on the import of Brazilian-harvested Brazil nuts in their shells, as the shells are considered to contain unsafe levels of aflatoxins, a potential cause of liver cancer.<ref name=eujournal>Template:Cite journal</ref>

Uses

Nutrition

Brazil nuts are 3% water, 14% protein, 12% carbohydrates, and 66% fats. The fat components are 16% saturated, 24% monounsaturated, and 24% polyunsaturated.<ref name=table>See USDA source in nutrition table.</ref>

In a Template:Convert reference amount, Brazil nuts supply 659 calories, and are a rich source (20% or more of the Daily Value, DV) of dietary fiber (30% DV), thiamin (54% DV), vitamin E (38% DV), magnesium (106% DV), phosphorus (104% DV), manganese (57% DV), and zinc (43% DV). Calcium, iron, and potassium are present in moderate amounts (10–19% DV).

Selenium

Brazil nuts are a particularly rich source of selenium, with just Template:Cvt supplying 544 micrograms of selenium or 10 times the DV of 55 micrograms.<ref name=table/><ref name="ods">Template:Cite web</ref> However, the amount of selenium within batches of nuts may vary considerably.<ref>Template:Cite journal</ref>

The high selenium content is used as a biomarker in studies of selenium intake and deficiency.<ref>Template:Cite journal</ref><ref name="Souza">Template:Cite journal</ref> Consumption of just one Brazil nut per day over 8 weeks was sufficient to restore selenium blood levels and increase HDL cholesterol in obese women.<ref name=Souza/>

Oil

File:Castanha-copl6.JPG

Brazil nut oil

Brazil nut oil contains 48% unsaturated fatty acids composed mainly of oleic and linoleic acids, the phytosterol, beta-sitosterol,<ref>Template:Cite journal</ref> and fat-soluble vitamin E.<ref>Template:Cite journal</ref>

The following table presents the composition of fatty acids in Brazil nut oil:<ref name=table/>

Palmitic acid	10%
Palmitoleic acid	0.2%
Stearic acid	6%
Oleic acid	24%
Linoleic acid	24%
Alpha-linolenic acid	0.04%
Saturated fats	16%
Unsaturated fats	48%

Wood

The lumber from Brazil nut trees (not to be confused with Brazilwood) is of excellent quality, having diverse uses from flooring to heavy construction.<ref name=pfaf>Template:Cite web</ref> Logging the trees is prohibited by law in all three producing countries (Brazil, Bolivia, and Peru). Illegal extraction of timber and land clearances present continuing threats.<ref>Template:Cite news</ref> In Brazil, cutting down a Brazil nut tree requires previous authorization from the Brazilian Institute of Environment and Renewable Natural Resources.<ref>Template:Cite web</ref><ref>Template:Cite web</ref>

Other uses

Brazil nut oil is used as a lubricant in clocks<ref>Template:Cite book</ref> and in the manufacturing of paint and cosmetics, such as soap and perfume.<ref name=pfaf/> Because of its hardness, the Brazil nutshell is often pulverized and used as an abrasive to polish materials, such as metals and ceramics, in the same way as jeweler's rouge, while charcoal from the shells can be used to purify water.<ref name=pfaf/>

See also

• Brazil nut cake
• List of culinary nuts
• Official list of endangered flora of Brazil
• Granular convection, also known as the "Brazil nut effect"