EARLY colonisation of the infant gut by specific Bifidobacterium strains was linked to a significantly reduced allergy risk in childhood, according to new research that highlighted the importance of microbial exposure and feeding practices in early life.
The study showed that early-life bifidobacteria capable of producing aromatic lactates helped shape immune tolerance, reducing food allergen-specific immunoglobulin E (IgE) and early eczema risk. These findings added mechanistic insight to long-standing observations that mode of birth, breastfeeding, and family environment influence allergy development.
Allergic diseases, including food allergy and atopic dermatitis, have increased markedly in recent decades, particularly in high-income countries. Food allergen sensitisation, reflected by allergen-specific IgE in blood, is considered an early marker of impaired immune tolerance and a risk factor for later allergic disease. Understanding how early-life exposures modify this risk has become a major research priority.
Early-Life Bifidobacteria and Allergy Risk
Researchers followed 147 children from birth to 5 years of age, analysing gut microbiota composition, microbial metabolites, and immune outcomes. Early transmission of aromatic-lactate-producing Bifidobacterium strains was more common in infants born vaginally, exposed to older siblings, and exclusively breastfed for the first 2 months of life.
This microbial profile was associated with higher concentrations of aromatic lactates in the infant gut, particularly 4-hydroxy-phenyllactate. Importantly, this microbiota–metabolite signature was inversely associated with the development of food allergen-specific IgE up to 5 years of age and with atopic dermatitis at 2 years.
Ex vivo experiments provided biological plausibility. The researchers demonstrated that 4-hydroxy-phenyllactate directly inhibited IgE production, while leaving immunoglobulin G responses unaffected, suggesting a selective effect on allergic sensitisation rather than global immune suppression.
Together, the findings defined an early-life microbiota–metabolite–immune axis linking microbial transmission and feeding practices to reduced allergy risk.
Implications for Prevention Strategies
The results supported growing interest in microbiota-targeted strategies to prevent allergic disease. Promoting conditions that support early-life bifidobacteria, such as breastfeeding and careful consideration of perinatal practices, could represent a low-risk approach to strengthening immune tolerance.
Future studies may explore whether targeted probiotics or microbial metabolites can safely replicate these protective effects.
Reference
Myers PN et al. Early-life colonisation by aromatic-lactate-producing bifidobacteria lowers the risk of allergic sensitisation. Nat Microbiol. 2026; DOI:10.1038/s41564-025-02244-9.
