Tree nut allergy: what to avoid, what you can eat and how to read labels

What counts as a tree nut, and what doesn’t?

Tree nuts are edible seeds from botanically unrelated trees. European food labelling law names eight, and they must always be emphasised on the label [1]: almond, hazelnut, walnut, cashew, pecan, Brazil nut, pistachio and macadamia nut [1].

Other foods are sold in the same bag but are not on that list. The peanut is a legume, related to peas and lentils, and the law treats it as a separate allergen [1]. The same applies to sesame and lupin [1]. Pine nuts, chestnuts and coconut are not among the eight, so labels are not required to emphasise them [1].

Most people with a tree nut allergy tolerate coconut, although reactions have been reported. Your allergist will advise you. Nutmeg is a spice, not a tree nut, and corn nuts are made from maize. Raisins, dried apricots and dates are dried fruit.

If you’re still unsure about the difference between an allergy and an intolerance, we explain it in our guide to food allergies and intolerances.

Do you need to avoid all tree nuts?

Not always—and this is the question we hear most often in consultations. Some tree nuts have similar proteins, which the immune system can mistake for one another. This is called cross-reactivity. Also, testing positive for sensitisation in a blood test and having a reaction when eating the food are two different things [2].

In a European study of children with a confirmed allergy to a tree nut, peanut or sesame, around six in ten reacted to more than one [3]. Put another way, four in ten could still eat the others. Some pairs are very commonly linked, such as pecan and walnut [3]. Cashew and pistachio also belong to the same botanical family.

That’s why your allergist should decide which foods to avoid, based on your history, skin or blood tests and, if needed, a supervised food challenge in hospital [2]. The recommendation is to avoid foods that cause a reaction [4]. Avoiding everything else “just in case” can make your diet less varied and make shopping more complicated.

Every tree nut you avoid without a reason is one less food on your plate and one more label to check.

Sometimes avoiding all tree nuts is recommended because it is easier to manage or because they may be mixed together during manufacturing. This can be a reasonable decision when made by the professional who knows your case. In children, tests are repeated over time because some allergies change [2].

If you have an LTP allergy

LTP, or lipid transfer protein, is a defence protein found in many plants. It withstands heat and digestion, so cooking or roasting the food does not deactivate it [5]. The best-studied LTP is found in peach, and this allergy has been described particularly in the Mediterranean region [5].

LTP is also found in tree nuts such as walnuts and hazelnuts, and in peanuts [5]. That is why, in our region, LTP is behind many tree nut allergies. Knowing exactly which protein triggers your reaction helps your allergist decide what you need to avoid [2].

Our guide to LTP allergy explains how to manage this allergy, fruit by fruit.

How to read a label without missing anything

On packaged food, allergens must be emphasised in the ingredients list, in bold, uppercase or a different colour [1]. Bakeries, pastry shops and restaurants must also provide this information, even when there is no label, and you can ask for it [1].

• Read the label every time, including on products you buy regularly, because recipes can change.
• Look for less obvious names such as praline, marzipan, gianduja or almond paste.
• Pine nuts, chestnuts and coconut are not highlighted, so look for them in the ingredients list.
• If there is no label and nobody knows what it contains, don’t eat it.

The statement “may contain traces” is voluntary. It warns that the food is made near tree nuts and could contain residues. There is no fixed amount behind the statement, and the law only requires that the information not be misleading [1].

Whether you also need to avoid these products depends on your allergy; your allergist will decide. Ask them to write this in your action plan so you know what to do when you’re standing in front of the shelf.

What can I put on my plate instead of tree nuts?

Tree nuts provide unsaturated fat, plant protein, fibre, vitamin E and minerals such as magnesium. None of these nutrients is unique to tree nuts, and a varied diet can easily provide them without tree nuts.

Good sources of fat include extra virgin olive oil, avocado, olives and oily fish, which also provides omega-3. Pulses and whole grains provide plant protein and fibre. Vitamin E is found in extra virgin olive oil and in seeds you tolerate.

For breakfast, try wholemeal toast with olive oil and tomato, or yoghurt with fruit and rolled oats. For crunch on soup or salad, try homemade croutons or chickpeas roasted in the oven.

Sunflower or pumpkin seeds are often a good alternative, but check with your allergist first. Sesame is another allergen and needs to be assessed separately. Be careful with hummus, whether homemade or shop-bought, as it usually contains tahini, a sesame paste.

Adrenaline auto-injectors and your action plan

If you have had a severe reaction or are at high risk, your allergist will assess whether you need an adrenaline auto-injector. Adrenaline injected into the muscle is the first-line treatment for anaphylaxis, a severe allergic reaction that affects several parts of the body at once [6].

Your allergist will decide the dose and how many auto-injectors to carry. You can learn how to use it and make sure the people you spend most of your time with know how to use it too [6].

Your action plan is a written document provided by your allergist. It explains which symptoms to watch for, when to use adrenaline and who to call. Keep it with your auto-injector and give a copy to your workplace or school.

If your child has the allergy

In the school canteen, every pupil with an allergy should have a written action plan [7]. Staff should be trained to recognise a reaction and use adrenaline [7]. Menus must clearly identify the allergens they contain [7].

Talk to the school management before the school year starts. Bring the allergy report and action plan. If your child has been prescribed an auto-injector, bring that too and ask where it will be kept and who knows how to use it.

Birthdays and school trips can be difficult. It often works well for your child to bring their own snack or treat and for the other families to know what they cannot eat. During adolescence, it helps to learn how to read labels and, if prescribed, to carry the auto-injector without relying on someone else.

What mistakes do we often see in consultations?

• Avoiding everything just in case. Tree nuts, seeds, coconut and even pulses, without any test indicating that this is necessary.
• Relying on the label from last time. Manufacturers change recipes and production lines.
• Thinking that roasting or baking makes it safe. Several of these proteins withstand heat [5].
• Leaving the auto-injector at home for a short outing. A reaction won’t wait until you get back.

And one question that often comes up at the end of an appointment: a specific diet does not make an allergy go away. A treatment that gradually increases tolerance is used for some children with peanut allergy [4]. It is always carried out under an allergist’s supervision, never at home on your own.