Senior Allergy Dietitian at the Royal Children’s Hospital, Clinician-Scientist Fellow at MCRI & Honorary Senior Research Fellow at Melbourne University,

Vicki McWilliam, MND, PhD

Multi-Nut OFC Feasible, Comparable to Home Introduction in Infants With Peanut Allergy, With Vicki McWilliam, MND, PhD

A supervised hospital-based multi-nut oral food challenge did not outperform standard home introduction in preventing tree nut allergy in peanut-allergic infants, according to preliminary data from the TreEAT trial — though the finding comes with an important safety reassurance and leaves open the question of whether the supervised approach confers benefits in parental anxiety and quality of life that the primary endpoint does not capture.

American Academy of Allergy, Asthma & Immunology (AAAAI)

 2026 Annual Meeting held in Philadelphia, Pennsylvania, from February 27 to March 2, 2026, by Vicki McWilliam, MND, PhD, Senior Allergy Dietitian at the Royal Children's Hospital, Clinician-Scientist Fellow at the Murdoch Children's Research Institute, and Honorary Senior Research Fellow at the University of Melbourne. 

sat down with McWilliam during the meeting to learn more. She described the study's origins in a practical clinical gap: in her Melbourne allergy clinics, families of peanut-allergic infants were routinely advised to introduce tree nuts at home without prior sensitization screening, yet only about 25% felt comfortable doing so. The multi-nut butter approach — blending almond, cashew, hazelnut, and walnut into a single product delivering 1 g of protein per nut per two-teaspoon dose — was designed to offer a supported, efficient alternative that could address parental anxiety while facilitating introduction across four allergens in a single hospital visit.

TreEAT enrolled 212 infants aged 4–11 months with confirmed peanut allergy (clinical history and peanut skin prick test ≥3 mm), randomized to either hospital-based multi-nut OFC (n = 107) or home introduction of individual nuts (n = 105), with tree nut sensitization not assessed prior to randomization. 

On the primary outcome — tree nut allergy at 18 months assessed by questionnaire, SPT, and OFC where indicated — preliminary complete case analysis showed no significant difference: 18.9% (n = 18/95; 95% CI, 11.6–28.3%) in the multi-nut OFC arm developed allergy to one or more tree nuts versus 12.4% (n = 11/89; 95% CI, 6.3–21.0%) in the home introduction arm, with cashew the most commonly implicated allergen. Peanut allergy resolved in 26.3% (n = 25/95; 95% CI, 18.0–36.7%) and 30.3% (n = 27/89; 95% CI, 22.0–42.1%) respectively. 

Critically, no infant in either group experienced anaphylaxis — a meaningful safety signal given that approximately 33% of infants were sensitized to tree nuts at baseline, yet true clinical allergy rates of 12–19% were substantially lower, reinforcing McWilliam's point that routine pre-screening risks driving unnecessary avoidance in this population. Ongoing analyses examining parental anxiety and quality of life outcomes may yet identify a meaningful advantage for the supervised multi-nut model where the primary endpoint did not.

“We did find it to be a successful and safe way to introduce the nuts in a combination product, which is maybe when we look at our quality of life outcomes and our parental anxiety outcomes, this might be something that comes out as a strong benefit of doing it as a multi nut butter versus doing it at home,” McWilliam said.

McWilliam’s reported disclosures include Nutricia

McWilliam V, Parker K, Koplin J, et al. The TreEat Study: A Randomized Controlled Trial Investigating the Efficacy and Safety of Early Introduction of Tree Nuts for the Prevention of Tree Nut Allergy in Infants with Peanut Allergy. Presented at: AAAAI 2026 Annual Meeting, February 27-March 2, Philadelphia, Pennsylvania. Abstract #L15

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McWilliam discussed findings from the TreEat study at AAAAI 2026.

Vicki McWilliam, MND, PhD

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