Itchy mouth after a handful of mixed nuts, but you never worked out which one? Brazil nuts turn up in nut mixes, muesli and chocolate, often next to five other nuts. Our test checks your blood for IgE antibodies to whole Brazil nut and to its main protein, Ber e 1, as part of 300 allergens and allergen components, so you can see whether you are sensitised to Brazil nut and to the nuts around it.
Brazil nut is the seed of a large South American rainforest tree. Its best known allergen is Ber e 1, a 2S albumin storage protein. It is unusually rich in sulphur-containing amino acids, and it keeps its shape through heat and digestion, so roasted nuts and baked goods carry it too.
Ber e 1 is the major Brazil nut allergen. It became famous in the 1990s, when it was moved into soybeans by genetic engineering and the modified beans then bound IgE from people with Brazil nut allergy. That project was stopped, but it showed how robust this protein is.
People describe itching or tingling in the mouth and throat, swollen lips, hives, stomach cramps or vomiting, usually within minutes to two hours of eating Brazil nut. Some report wheezing or feeling faint. Because Brazil nuts often come in mixes, many people only know that "something in the nuts" was the problem.
Swelling of the lips, tongue or throat, trouble breathing or feeling faint after eating is an emergency. Call 112 (EU) or your local emergency number. Do not wait for a test.
IgE to a nut shows that your immune system recognises it. It does not prove that you will react when you eat it. In a European study in which children with one nut allergy were challenged with all the others, most of them could go on to eat a long list of other nuts.
So use the result as a map. If you have never reacted to Brazil nut, do not cut it out on a result alone. If you have reacted to a nut mix, the pattern across Brazil nut, hazelnut, walnut, cashew and the rest gives your doctor a clear place to start.
The lab measures IgE to a whole Brazil nut extract and to Ber e 1 on its own. Your lab report gives each a measured value and class, from Negative to Very high, next to every other tree nut, peanut and seed on the panel. Treat it as a pattern to discuss with your doctor, not a diet plan.
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One finger-prick sample checks IgE to 300 allergens and allergen components, from birch and peanut to cat and house dust mite. Post it to the lab, and about 5 days after it arrives you get a value for every one. Our plain-English guide shows you how to read them. €399 in total, €1.33 per allergen.
Yes. For allergy purposes, Brazil nut counts as a tree nut and is on the EU list of nuts that must be declared on food labels. Botanically it is a seed from a different plant family than hazelnut or walnut, which is why results across nuts can differ.
Not necessarily. Many people who react to one nut eat others without problems. Your report shows each nut separately, so a doctor can see which ones your antibodies recognise and decide which, if any, need a closer look.
Not reliably. Ber e 1 is stable to heat and digestion, so roasted nuts, baked goods and chocolate-coated nuts still contain it. If you have reacted to Brazil nut before, ask your doctor what applies to you.
