Introducing Tree Nuts to Your Baby, One Nut at a Time

The label "tree nuts" covers almond, cashew, walnut, hazelnut, pistachio, pecan, Brazil nut and macadamia. They are botanically unrelated to each other and a child can be allergic to one and eat the rest without trouble. In children, cashew and walnut come up most often, and hazelnut is more common in Europe than elsewhere (systematic review of tree nut allergy prevalence, 2015). The same review notes that cashew and pistachio tend to travel together, as do walnut and pecan, which is worth mentioning to your doctor if one of them causes a problem.

Peanut sits outside this list entirely. It is a legume, grown underground, and is handled as its own allergen, which is why we ran peanut as a completely separate introduction. Peanut going well told us nothing about cashew, and we had to stop treating the two as a single milestone.

ASCIA's advice is to use smooth nut butters and pastes, powder, or finely ground nuts such as almond meal, and not whole nuts or pieces. We did three things. Smooth nut butter, thinned with warm water, breast milk or plain yoghurt until it ran off the spoon like runny yoghurt, never a thick blob. Almond meal or ground walnut stirred through porridge, about a teaspoon. And later, ground nuts baked into a soft muffin.

The rule we kept in our heads: nothing with texture. NHS guidance is that whole nuts should not be given to children under five because of the choking risk, and a thick spoonful of nut butter behaves much the same way in a small airway. Chunky or crunchy butters were out. If you want the wider picture on shape and texture, we wrote up the choking-hazard list separately.

We used the same rhythm we had used for egg. Day 1: a smear of thinned nut butter, maybe a quarter teaspoon, in the morning at home with the rest of the day clear. Day 3: half a teaspoon. Day 7: a full teaspoon, or ground nut in porridge. Day 14: the nut as an ordinary part of meals. No other new food went into those two weeks, so anything odd had only one candidate.

We started with almond because it was already in the house, then cashew, then walnut. Three nuts took us about six weeks, and we did not attempt all eight. Our paediatrician was relaxed about that and suggested covering the ones that actually appear in our cooking. Most reactions show up within minutes to two hours, though not all, which is the reasoning behind the longer observation window.

Mixed nut butters and multi-nut spreads are sold as a tidy shortcut, and the appeal is obvious when you are looking at eight foods and a calendar. The honest trade-off is that a reaction to a five-nut paste tells you almost nothing. You know the baby reacted. You do not know to what, and working it out afterwards usually means testing or a supervised challenge.

ASCIA's position in its infant feeding and allergy prevention guidance is to introduce only one new allergen at the same meal, precisely so the trigger can be identified. We took that literally and ran the nuts one at a time. A mixed butter became useful afterwards, as an easy way to keep several known-tolerated nuts in rotation each week. Which order, and whether a combined product is reasonable for your baby, is a decision for your doctor rather than for us.

The part we nearly missed is that introduction is not the finish line. ASCIA advises that once a food has been eaten without a reaction, it keeps being offered at least once a week, because dropping it again may raise the risk of an allergy developing. Tree nuts are easy to forget, so they went onto the weekly list next to sesame.

Labels are the other thing worth learning early. "Tree nuts" is a single declarable category on the US FDA list of nine allergens, while the EU and UK list of fourteen names the individual nuts, so a European label will often tell you it is hazelnut where an American one may say only tree nuts. If your baby ends up reacting to one specific nut, that difference stops being academic at the supermarket.