Q&A: Neonatal gut microbiome enterotype may impact egg white sensitization odds
Key takeaways:
- The adjusted odds ratio for egg white sensitization development at 2 years old with Bifidobacterium- vs. Bacteroides-dominant enterotypes was 0.1.
- The next step in this research is animal models.
Specific enterotypes of the gut microbiota in infants aged 1 month may have an impact on the likelihood for food sensitization to egg whites, according to results published in The Journal of Allergy and Clinical Immunology.
The microbiome data in this study were derived from two Japanese studies: the Chiba High-risk Birth-cohort for Allergy (CHIBA) study and the Katsushika study.

According to researchers, the odds for development of sensitization to hen egg whites was significantly decreased with Bifidobacterium-dominant enterotypes in the gut microbiota of 1-month-olds vs. Klebsiella-dominant and Bacteroides-dominant enterotypes.
For example, the adjusted odds ratio for hen egg white sensitization development at 2 years old with Bifidobacterium-dominant vs. Bacteroides-dominant enterotypes in CHIBA was 0.1 (95% CI, 0.01-0.78). The study reported the same adjusted odds ratio (95% CI, 0.01-0.77) when placing Bifidobacterium-dominant against Klebsiella-dominant enterotypes in the CHIBA cohort.
As previously covered on Healio, Danielle Crumble Smith, RDN, with Top Nutrition Coaching, said “oral supplementation with specific probiotic strains, such as Ligilactobacillus salivarius and Bifidobacterium bifidum, has been shown to effectively reduce the risk for atopic sensitization to common allergens.”
Healio spoke with study author Hiroshi Ohno, MD, PhD, deputy director and team leader of the laboratory for intestinal ecosystem at the RIKEN Center for Integrative Medical Sciences, to learn more about gut microbiota development, its relationship with food sensitization/allergy and next steps in this research.
Healio: What prompted this study?
Ohno: It has become clearer that the condition of the gut microbiome in early infancy affects the pathogenesis of childhood food allergies, but no detailed analysis of the relationship, especially in Japan, has been done. This led us to conduct this study.
Healio: What are the biggest factors that impact the development of the gut microbiota?
Ohno: One of the biggest factors impacting gut microbiota development during infancy is the diet. During the first several months with milk (regardless of breast or formula), the microbiota is composed of predominant Bifidobacterium and some other bacteria, including Escherichia coli. The microbiota starts approaching that of adults with Bacillota (formerly Firmicutes) and Bacteroidota (formerly Bacteroidetes) becoming predominant when the kids start eating solid foods.
Another big factor would be the mode of delivery (vaginal or cesarean section) that shapes the normal development of gut microbiota especially during early infancy followed by the presence of an older sibling, and also transferring from mother and other family members.
Healio: How does the gut microbiota impact the development of food allergy?
Ohno: Even though certain gut microbial composition, such as the less abundant Bifidobacterium, could associate with the later development of food allergies, there is no causal relationship apparent from this kind of human observational study, and it requires follow-up confirmation experiments with animal models to clarify the causal relationships.
Healio: How can doctors use these associations between specific bacteria and food allergies to mitigate or even prevent allergies in children?
Ohno: One such possibility is the use of Bifidobacterium probiotics, as suggested by literature.
Healio: What is the next step in this research?
Ohno: To unveil mechanistic understanding, validation with animal model studies is necessary, but it would be difficult without more precise human data.
References:
- Infant gut bacteria and food allergies: the good, the bad, and the ugly. https://www.eurekalert.org/news-releases/1072143. Published Jan. 30, 2025. Accessed Jan. 30, 2025.
- Shibata R, et al. J Allergy Clin Immunol. 2024;doi:10.1016/j.jaci.2024.10.029.
For more information:
Hiroshi Ohno, MD, PhD, can be reached at hiroshi.ohno@riken.jp.