Scientists discovered that babies who develop a type of food allergy called allergic proctocolitis have different gut bacteria than healthy babies. Some bacteria like E. coli were more common in babies with the allergy, while protective bacteria were less common. Interestingly, these bacterial differences sometimes appeared before babies showed any symptoms. The study also found that certain bacteria produce fewer helpful substances called short-chain fatty acids during the allergic reaction. These findings could help doctors identify which babies might develop food allergies early and develop new treatments to prevent them.
The Quick Take
- What they studied: How the types and specific strains of bacteria living in babies’ stomachs differ between those who develop food allergies and those who don’t
- Who participated: Infants with allergic proctocolitis (a food allergy condition) compared to healthy infants without the condition. The exact number of babies wasn’t specified in the abstract
- Key finding: Babies with food allergies had more E. coli and certain Bifidobacterium bacteria, while healthy babies had more protective bacteria like Bifidobacterium breve. Some bacterial differences appeared before symptoms started
- What it means for you: This research suggests doctors might eventually be able to identify babies at risk for food allergies by testing their gut bacteria early. However, this is early-stage research and not yet ready for clinical use
The Research Details
Researchers compared the gut bacteria of infants with allergic proctocolitis to healthy control infants. They used advanced genetic testing to identify not just which bacteria were present, but also the specific strains (like different varieties of the same bacterial species) and what genes those bacteria carried. This detailed approach allowed them to see patterns that simpler testing might miss. The scientists also looked at what functions these bacteria performed, particularly focusing on the production of short-chain fatty acids, which are important chemicals that help protect the intestinal lining.
Looking at bacteria at the strain level (specific varieties) rather than just the species level is important because different strains of the same bacteria can behave very differently. This detailed approach revealed disease-specific patterns that wouldn’t have been visible with simpler testing methods. Understanding these patterns helps scientists figure out which bacteria might be causing problems and which might be protective.
This is original research published on Research Square, a preprint platform. The study appears to be the first comprehensive strain-level analysis of gut bacteria in this specific food allergy condition. However, because the sample size wasn’t specified in the abstract, readers should consider this preliminary research that will need confirmation in larger studies before clinical recommendations can be made.
What the Results Show
The most striking finding was that babies with allergic proctocolitis had significantly different bacterial communities compared to healthy babies. Specifically, E. coli and certain Bifidobacterium bifidum strains were much more abundant in babies with the allergy. In contrast, protective bacteria like Bifidobacterium breve and Klebsiella species were more common in healthy babies. When researchers looked even more closely at individual bacterial strains, they found that specific E. coli strains associated with the allergy had genes for making biofilms and sticking to intestinal cells—abilities that might help them cause problems. Interestingly, some of these bacterial differences were detectable even before babies developed symptoms, suggesting these changes might come before the allergy develops rather than being caused by it.
The study found that babies taking probiotics (beneficial bacteria supplements) had more Lacticaseibacillus rhamnosus strains, and these were more common in babies with allergies. The research also revealed changes in short-chain fatty acids, which are protective substances produced by gut bacteria. During the allergic reaction phase, babies had reduced production of these protective fatty acids. However, after the allergy resolved, production of these fatty acids increased again, suggesting the body might be trying to repair the damage.
This is described as the first comprehensive strain-level study of gut bacteria in allergic proctocolitis. Previous research has suggested that gut bacteria play a role in food allergies, but this study provides much more detailed information about which specific bacterial strains are involved and what genes they carry. The findings support the growing understanding that early-life gut bacteria composition influences how the immune system develops and responds to food proteins.
The study abstract doesn’t specify how many infants were included, making it difficult to assess the statistical power. The research appears to be observational, meaning it shows associations between bacteria and allergies but cannot prove that specific bacteria cause the allergy. Additionally, the study was conducted at a specific time point, so it’s unclear how bacterial patterns change over time or whether they differ in different populations or geographic regions.
The Bottom Line
This research is too preliminary for clinical recommendations at this time. It suggests that future screening tests based on gut bacteria might help identify at-risk infants, but such tests don’t exist yet. Parents should continue following standard medical advice for food allergy prevention and management. If your infant shows signs of food allergy (bloody stools, severe discomfort), consult your pediatrician immediately.
This research is most relevant to parents of infants with food allergies, pediatricians specializing in allergies, and researchers studying food allergies and gut health. It may eventually be relevant to all parents interested in food allergy prevention, but that application is years away. This research does not apply to older children or adults with food allergies.
This is basic research aimed at understanding disease mechanisms. Practical applications like diagnostic tests or new treatments are likely several years away and would require additional studies to confirm these findings and test interventions.
Want to Apply This Research?
- Track stool characteristics (color, consistency, presence of blood) and timing of symptoms in relation to food introductions. Note any probiotic use and brand names. This data could be valuable if discussing results with your pediatrician
- If your infant has been diagnosed with allergic proctocolitis, work with your pediatrician to document which foods trigger symptoms and track recovery patterns. Keep detailed notes about any probiotic supplements used, as this research suggests they may affect gut bacteria composition
- Maintain a symptom diary including stool changes, feeding times, and any dietary modifications. Share this information with your pediatrician to help identify patterns and track whether symptoms improve over time
This research is preliminary and has not yet been peer-reviewed through traditional journal processes. It describes associations between gut bacteria and food allergies but does not prove cause-and-effect relationships. These findings are not yet ready for clinical application. If your infant shows signs of food allergy (bloody stools, severe discomfort, vomiting, or failure to gain weight), contact your pediatrician immediately. Do not make changes to your infant’s diet or use probiotics without consulting your healthcare provider. This information is educational only and should not replace professional medical advice.