Maternal allergy status, infant birth season impact milk microbiome of mothers
Key takeaways:
- Season of birth appeared associated with significant influence on human milk microbiome composition.
- Milk microbiome varied depending on the type of maternal allergic disease.
Researchers identified a strong correlation between the milk microbiome of mothers with allergic disease and the season of infant birth, according to study results published in Allergy.
“Clinicians can now use this evidence to consider maternal allergy status and birth season when assessing infant risk factors,” Donna Geddes, PhD, professor at The University of Western Australia (UWA) and director of the UWA Centre for Human Lactation Research and Translation, Australia, told Healio. “The [data reveal] that different types of maternal allergies may have differential effects on breast milk composition. These insights could help design future research to identify key components in milk that impact infant allergy risk and enable development of evidence-based supplementation/therapies for further testing.”
‘Rising prevalence’
“The rising prevalence of allergic diseases, particularly in industrialized countries, has become a significant concern,” Geddes said. “Early infancy represents a critical window for immune development, yet there was a notable knowledge gap regarding how maternal allergic disease affects breast milk composition. With approximately one in four mothers experiencing allergic disease, we believe understanding how this affects their breast milk microbiome — the most important factor in shaping the infant gut microbiome — is essential, especially given the literature details conflicting evidence about the potential role of breastfeeding in reducing the risk of allergies in infants.”
Researchers sought to characterize the milk microbiome of 196 mothers with allergic disease. They conducted full-length 16S ribosomal RNA gene sequencing of milk samples collected at 3 months and 6 months and then constructed multivariate linear mixed models to identify the maternal, infant and environmental determinants of the milk microbiome.
Milk microbiome
According to study results, human milk microbiome composition and beta diversity varied over time (permutational multivariate analysis of variance, R2 = 0.011; P = .011).
Researchers observed season of infant birth as the strongest determinant of milk microbiome community structure (permutational multivariate analysis of variance, R2 = 0.014; P = .011).
In addition, data showed that the milk microbiome varied depending on the type of maternal allergic disease, such as allergic rhinitis, asthma, atopic dermatitis and food allergy.
“The positive association between allergic rhinitis and milk microbiome diversity was unexpected, as it contradicted previous findings in nasal and gut microbiome studies,” Geddes said. “The distinct patterns of microbiome changes associated with different types of allergic diseases were also unanticipated findings.”
Of note, researchers also found that exposure to infant formula reduced the relative abundance of various oral taxa commonly found in milk.
Future research
“Future larger studies should investigate the relationship between seasonal variations and allergic disease in larger cohorts, examine the link between maternal milk microbiome patterns and child allergy outcomes, and include nonallergic control groups for comparison,” Geddes said. “There is also a need to explore the mechanisms behind season-specific changes in milk composition and understand how these findings could be applied to allergy prevention strategies.
“When building upon this research, it will be important to include maternal and infant fecal samples in order to determine their roles in mediating risk of infant allergy,” she added.
For more information:
Donna Geddes, PhD, can be reached at donna.geddes@uwa.edu.au.