A recent study published in the Journal of Allergy and Clinical Immunology found that certain gut bacteria found in one-month-old infants were associated with sensitivities and the development of food allergies—particularly to eggs—while others were not. The researchers also determined factors that could predict which strains of bacteria would be present in newborns’ guts.
The gut microbiome, which includes bacteria, helps develop the immune system and protects against certain diseases. However, the link between gut microbiota, food allergies, and sensitivities is complex and challenging to unravel.
A food allergy develops when the body mistakenly perceives an otherwise benign food protein as dangerous and mounts an immune system response. That response is in the form of antibodies known as immunoglobulin E (IgE), each specialized to respond to the food protein the body believes is harmful.
The study, led by Hiroshi Ohno at the RIKEN Center for Integrative Medical Sciences, analyzed the gut bacteria from two cohorts of Japanese children beginning at birth. One was a high-risk group of 270 families with histories of food allergies, and the other was a group of 245 children from a previous study that aimed to test allergy treatments.
They looked at IgE levels corresponding to milk, peanut, egg white and wheat in the blood from one year after birth until the children were 7 years old. They also collected data from gut microbiota from one week after birth and analyzed both, hoping to find predictable gut microbiota signatures for food allergies and sensitization.
Their first finding was that the gut microbiota present one month after birth were most related to food-specific IgE levels in the blood, even over samples analyzed over the next 7 years.
Said Ohno:
We know that the early neonatal period is critical for immune system development and our results emphasize this, showing that the type of bacteria in the gut at this critical time is the best at predicting immune responses to food seven years down the road.
Their analysis segregated microbiota into groups that varied over time. By focusing on the three most common bacteria that dominated infant microbiomes at one month, they determined that infants with type-3, Bifidobacterium-dominant microbiomes were significantly less likely to develop food sensitization to egg whites than babies whose microbiomes were dominated by one of the other categories of bacteria, a trend for allergic reactions to egg whites later in life.
To determine the kinds of bacteria an infant has at one month after birth, the researchers analyzed other data available for the 515 children in the study. They found that the type of delivery and the amount of breastfeeding were linked to the gut microbiota.
Infants who were delivered vaginally and received a relatively shorter period of breastfeeding had the best result: type-3, Bifidobacterium-dominant microbiomes. Type-1 microbiota dominated when births were vaginal, but breastfeeding was high, while type-2 microbiota dominated with Cesarian births, and the amount of breastfeeding was low.
The findings suggest that specific probiotic supplements might be a good early defense for preventing food allergies, especially for at-risk infants.
Said Ohno:
We conducted this study in the hope that a better understanding of neonatal gut microbiota would help generate ideas for allergy prevention strategies. We found that these microbiota do correlate with food allergens-specific serum IgE levels, and that intervention with Bifidobacterium during infancy might help prevent later food allergies, especially in infants who are the most at risk.
