Susanne Brix Pedersen

For years, avoiding food allergens in early life was the standard advice. However, new research shows this is not always the case.

Vaginal delivery, exclusive breastfeeding, and early exposure to siblings emerged as the strongest drivers of colonization with allergy-protective gut bacteria in infancy, offering clinicians a concrete context for how early-life exposures may shape long-term immune risk.

Published on: Longitudinal data identify aromatic lactate–producing bifidobacteria and the metabolite 4-hydroxy-phenyllactate as key factors in early immune tolerance. Infants colonized early with specific bifidobacteria that produce aromatic lactate metabolites were significantly less likely to develop allergic sensitization and atopic dermatitis in childhood, according to new longitudinal data published in Nature Microbiology.