Brazil nut is the seed of the Bertholletia excelsa tree (Family Lecythidaceae).
The Brazil nut is actually the seed of a giant tree that grows wild in South America's Amazon jungle. The seeds, about 6cm long, come in clusters of 8 to 25 inside a large, hard, thick-walled globular pod that resembles a coconut and weighs up to 2 kg. The extremely hard shell of each seed, or "nut, is dark-brown and three-sided. The kernel is white and high in fat, containing 70% oil and 17% protein. When fresh, it is highly esteemed for its rich flavour but becomes rancid in a short time from the great quantity of oil it contains. Except for its close relative the Paradise nut, it is unrelated to all other foods.
The monetary value of Brazil nut exportation today from the Amazon (nearly all from wild trees), begun in the 1600's by Dutch and Portuguese traders, is second only to that of rubber.
In the Amazon, indigenous tribes eat the nuts raw, or they are grated and mixed into gruels, often along with Manioc flour. Their plentiful oil is used in cooking. Exported, the nuts are a snack food, and their oil is prized. In addition to protein and fat, Brazil Nuts are a substantial source of selenium, an important antioxidant. The proteins make up 15-17% of its fresh weight and 50% of defatted flour. Of these, storage proteins are the most important ones, and the 12 S globulin legumin-like protein and the 2 S albumin have been described as the most representative. The 2 S protein is high in sulfur-rich amino acid content (3-8% cysteine and 18% methionine). (Bartolome 1997 ref.625 64) The protein is also extremely rich in glutamine, glutamic acid, and arginine.
The tree bark is brewed into tea to treat liver ailments. The husks of the seed pods have also been brewed to treat stomachaches.
Brazil nut may be a "hidden" allergen in cookies, etc. The oil extracted from the nuts is commonly used in Peru and other South American countries to manufacture soap, and for lighting, and the empty pods are used as implements and burned to repel insects. Worldwide, Brazil nut oil is often used in soaps, shampoos, hair conditioning/repair products, and skin moisturisers, and extracts of the pods can figure in insect repellants.
Ber e 1, a 2S albumin, 9 kDa, resistant to digestion by pepsin (Murtagh 2001 ref.7794 4) (Alcocer 2002 ref.7795 5) (Pastorello 1998 ref.4333 5) (Pastorello 2001 ref.4135) (Bartolome 1997 ref.625 64) (Gander 1991 ref.5083 5)
Ber e 2, an 11S Globulin-like Protein
Other several allergenic fractions including a 12S globulin protein, a legumin-like storage globulin. (Bartolome 1997 ref.625 64)
This study reports on 11 patients with anaphylaxis after eating Brazil nuts and 10 subjects with no symptoms to this food item although both groups had specific IgE to Brazil nut. A number of allergenic components with molecular weights ranging from 4 to 58 kd have been isolated. All sera from symptomatic patients recognized a 9-kd allergen corresponding to a 2S albumin (a major allergen) of Brazil nut, whereas the other allergens each bound IgE from less than 50% of sera. No sera from asymptomatic subjects showed IgE binding to the 9-kd allergen, but they did recognize components from 25 to 58 kd, which are minor allergens. (Pastorello 1998 ref.4333 5)
The 2S albumin is probably a major Brazil-nut allergen. (Nordlee 1995 ref.875 21)
The Brazil nut 2S albumin has been recognized as a methionine-rich protein that could be used to increase the nutritional value of certain foods through genetic engineering techniques. However, the 2S albumin of the Brazil nut is also the major allergen of Brazil nuts (Ber e 1), as it shows IgE-reactivity with more than 80% of the sera from our Brazil-nut allergic subjects. (Oommen 2000 ref.3536 1) (Nordlee 1996 ref.2508 1) (Lehrer 1997 ref.2545 3)
Allergy to minor allergens of 18 kDa, 25 kDa, 33 kDa and 45 kDa have been reported. (Asero 2002 ref.7026 8)
The important food allergen Brazil nut 2S albumin is as stable to digestion as is sunflower seed 2S albumin. (Murtagh 2003 ref.8310 1)
IGE AND IMMUNE:
Allergic reactions. Anaphylaxis. (Arshad 1991 ref.284 21) Vomiting, diarrhoea and loss of consciousness. (Bartolome 1997 ref.625 94)
The probability of a patient with nut allergy having specific IgE to a particular combination of peanut, hazelnut and brazil nut is similar, whatever their age or sex. The apparent increase in multiple nut reactivity with increasing age may therefore be due to exposure of previously unchallenged sensitivity. The frequency of multiple-nut specificity is sufficiently high that patients should always be tested for allergy to a range on nuts if they have a history of reacting to any nut. (Pumphrey 1999 ref.7807 4)
In a study of 62 patients with nut allergy (adults and children), peanuts were the commonest cause of allergy (47), followed by Brazil nut (18), almond (14), and hazelnut (13). (Ewan 1996 ref.1625 87)
The seed storage 2S albumin, has been identified in the most diffused edible seeds and nuts, such as mustard, sesame, Brazil nut, walnut and peanut. In particular, a strong correlation between IgE-binding to these proteins and food-induced anaphylaxis has been demonstrated for Brazil nut and sesame seeds. (Pastorello 2001 ref.4135)
Anaphylaxis. (Borja 1999 ref.7806 4)
Patients sensitized to minor Brazil nut allergens are reported to not have allergic symptoms (Pastorello 1998 ref.4333 5) but this is contradicted by a study of a 15 year old boy who experienced two distinct episodes of generalized urticaria about 30 minutes after eating Brazil nut. A SPT was very positive to Brazil nut. Serum IgE was positive to Brazil nut but negative to mustard, poppy seed, sesame seed or sunflower seed (no reactivity shown to 2S albumins) (Asero 2002 ref.7026 8)
The effects on iron absorption of nuts were measured in 137 Indian women. When the absorption from bread and nut meals (walnuts, almonds, peanuts, and hazelnuts) was compared with that from bread meals, the overall geometric mean absorption from the nut meals (1.8%) was significantly less than from the bread meals alone (6.6%). In contrast, coconut did not reduce absorption significantly. All the nuts tested contained significant amounts of two known inhibitors of Fe absorption (phytates and polyphenols) but the amounts in coconut were significantly less than in the other nuts. Fifty milligrams ascorbic acid overcame the inhibitory effects of two nuts that were tested (Brazil nuts and peanuts). This is different from that found previously for soy protein, another potent inhibitor of Fe absorption. (Macfarlane 1988 ref.7810 1)
Intestinal obstruction and perforation due to an ingested Brazil nut. (Durdey 1985 ref.7812 2)
Information supplied from an abridged section of:
Allergy Advisor - Zing Solutions
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