Infant Gut Bacteria Linked to Lower Allergy Risk: New Study Findings
- New research suggests a strong link between the composition of gut bacteria in early infancy and a reduced risk of developing allergies and atopic dermatitis.
- Investigators at the Technical University of Denmark (DTU) followed a cohort of 147 children from birth to age five, collecting serial fecal samples at eight time points, along...
- The key finding centers around aromatic lactate-producing bifidobacteria.
New research suggests a strong link between the composition of gut bacteria in early infancy and a reduced risk of developing allergies and atopic dermatitis. Published in Nature Microbiology on , the study identifies specific bifidobacteria that, when present in infants, appear to promote immune tolerance and lower the likelihood of allergic sensitization.
Investigators at the Technical University of Denmark (DTU) followed a cohort of 147 children from birth to age five, collecting serial fecal samples at eight time points, along with maternal samples, blood draws and clinical data. The research focused on identifying a connection between the gut microbiome, metabolic processes, and immune responses related to food allergies. The study aimed to determine if specific bacterial compositions in early life could prevent certain diseases.
The key finding centers around aromatic lactate-producing bifidobacteria. Infants with a high abundance of these bacteria, particularly during the first six months of life, exhibited elevated levels of aromatic lactates in their gut and a significantly lower risk of developing food allergen-specific immunoglobulin E (IgE) antibodies through age five. These infants showed reduced rates of atopic dermatitis, commonly known as eczema, at two years of age.
The protective effect appears to be mediated by a bacterial metabolite called 4-hydroxy-phenyllactate (4-OH-PLA). Laboratory studies demonstrated that 4-OH-PLA selectively inhibited IgE production in human immune cells without affecting the production of IgG, another type of antibody. This suggests a targeted mechanism by which these bacteria influence the immune system.
“Even though we see that [4-hydroxy-phenyllactate] can reduce IGE production…in human immune cell populations, we don’t know exactly why,” said investigator Susanne Brix Pedersen, professor at DTU Bioengineering. “We know that humans, but not other animals except chimpanzees…have a specific receptor that can bind to these aromatic lactates, but we haven’t been able to see that it’s mediated via these receptors yet, so it might be other routes for interaction with the immune cells that has just not been discovered yet, but we do see this reduction.”
The study also highlighted the importance of early-life exposures in shaping the infant gut microbiome. Vaginal delivery, exclusive breastfeeding for the first two months, and exposure to older siblings were all associated with a higher colonization rate of these beneficial bifidobacteria. Infants delivered vaginally were up to 14 times more likely to acquire these strains from their mothers.
Researchers analyzed gut bacteria data from two long-term studies, one involving 270 children with a family history of allergies (a higher-risk group) and another including 245 children from a previous allergy treatment study. This allowed them to correlate early gut bacteria patterns with the later development of allergies.
A separate study, conducted by Azad et al. In 2013, also found that infants with a lower diversity of gut microbiota were at a higher risk of developing allergies later in life.
The findings suggest that certain types of bacteria are linked to food sensitization, while others do not appear to contribute to this risk. Researchers identified six different “enterotypes” – distinct patterns of gut bacteria – across all the children in the study.
While these findings are promising, it’s important to note that the study demonstrates an association, not necessarily causation. Pedersen emphasized that further research is needed to confirm a causal link. A larger study involving 1000 Danish infants is currently underway to investigate this relationship in more detail.
“There’s no causal link at this moment,” Pederson said. “As I see it, we have this prospective study where we see associations, but we don’t have any studies that have been designed to actually look at the causal interaction at this moment, but we are undertaking a bigger study in 1000 Danish infants, where we are trying to…investigate this in detail.”
If these findings are confirmed, they could pave the way for new preventive strategies aimed at reducing the global burden of childhood allergies, and asthma. Potential strategies include targeted probiotic supplements or the development of infant formulas enriched with these beneficial bacteria or their metabolites.
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