Beware of biscuits: a nut allergy can be dangerous

Anna Sandner

12/12/2023

Translation: machine translated

Nut allergies vary according to age. Here's why nut biscuits generally pose no problem for allergic adults, but can be dangerous for allergic children. You can also find out how to tell the difference between real and fake nuts.

Advent time is in full swing and what's not to miss? Of course, little Christmas biscuits! Now, many biscuit recipes contain nuts. What for some is a healthy ingredient in Christmas treats can have harmful consequences for others, namely when an allergic reaction occurs.

Advice to adult nut lovers

For most adults and young people, a nut allergy is nothing to worry about. In fact, it is usually a "secondary allergy", i.e. a cross-reaction due to a pollen allergy. As the allergens in some nuts are similar to those in birch pollen that trigger hay fever, allergic reactions occur when we eat nuts. This "pollen-associated food allergy" then causes itching in the mouth.

Adults who love biscuits can breathe easy, however: the heat of baking destroys the allergenic proteins in nut biscuits. So there's nothing to stop you enjoying biscuits, even if you have a nut allergy.

Nut allergy: caution in children

In contrast, nut allergy in children is less easy to manage. It is generally a primary allergy to nuts, which can develop independently of a pollen allergy in the first few years of life. In many children with atopic dermatitis, it develops as a result of skin contact with nut allergens that can be found all over the house. This form of nut allergy can lead to serious, even fatal, allergic reactions, warn researchers from the GFO clinics in Bonn and the Charité in Berlin (in German). What's more, as these allergenic proteins to which children react are not destroyed by heat, nut biscuits can cause an allergic reaction.

Some nuts aren't really nuts

There is, however, a small consolation for those who wish to eat nuts despite their allergy. For one thing, people with allergies often only react to the proteins in a certain type of nut. A doctor can determine which of these by means of IgE antibodies. On the other hand, not everything that is called a "nut" in everyday language is actually a nut from a botanical point of view. However, identification is not straightforward. Seeds and fruits are named according to the floral structures from which they develop. And it's not uncommon for scientists (especially internet users) to disagree about what really is a nut and what isn't.

If we refer to botany textbooks, almonds and pistachios are stone fruits. As far as cashews are concerned, the systematics are not entirely clear. Are they stone fruits or nuts? Yet some people are allergic to stone fruits. Regardless of the biological subtleties, caution is therefore advised when in doubt: as with peanuts, which are certainly not a real nut but a legume, but which can nonetheless cause an allergic reaction. True nuts in the botanical sense of the term are: hazelnut, chestnut, macadamia nut, Brazil nut, pecan and walnut fruit.

Now you know everything! So, get your (nut-free) biscuits, ready, set, go!

You'll find more than just macadamia nuts.

Further information on the subject of nut allergy can be found on the page of the Centre for Allergy Switzerland.

Anna Sandner

Editor

Anna.Sandner@galaxus.de

Science editor and biologist. I love animals and am fascinated by plants, their abilities and everything you can do with them. That's why my favourite place is always outside - somewhere in nature, preferably in my wild garden.

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