How ‘Friendly’ Bacteria May Help Infants Improve Their Immune System

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Researchers at found a connection between a beneficial gut bacteria and immune system development. Natalie McComas/Getty Images
  • Researchers at the Karolinska Institute found a connection between breastfeeding, beneficial gut bacteria, and immune system development.
  • A “friendly” strain of bacteria available in breast milk may help infants develop robust gut health.
  • For infants who aren’t breastfed, supplements may be an option to consider.

New research finds there’s a critical time for priming immune system development and reducing systemic inflammation in the first 100 days after birth.

Researchers at the Karolinska Institute in Sweden found a connection between breastfeeding, beneficial gut bacteria, and immune system development.

The study, published this month in the journal Cell, is the first to show how a strain of “friendly” bacteria called activated Bifidobacterium infantis EVC001 (B. infantis) influences immune system development in infants, and could reduce the risk of allergic and autoimmune conditions later in life.

“This study and some early data from other sources including human and animal studies seems to imply that there could be correlation between the presence of beneficial gut bacteria in infants and a protection from the development of allergic diseases,” Punita Ponda, MD, assistant chief in the division of allergy and immunology at Northwell Health in New York, told Healthline.

The study included 208 breastfed babies born at Karolinska University Hospital in Sweden between 2014 and 2019.

Researchers used novel methods to analyze the immune system from small blood samples, since it would be unethical to perform biopsies on these babies.

The University of California followed a second group, which included infants who were exclusively breastfed, with half given a B. infantis supplement, and then analyzed for intestinal inflammation.

Researchers found that infants who lacked B. infantis, which is able to metabolize beneficial sugars in breast milk called human milk oligosaccharides (HMOs), had disordered development of immune cell networks and increased systemic inflammation.

“A possible application of our results is a preventative method for reducing the risk of allergies, asthma and autoimmune disease later in life by helping the immune system to establish its regulatory mechanisms,” Petter Brodin, pediatrician and researcher at the Karolinska Institute Department of Women’s and Children’s Health, and one of the study authors, said in a statement.

Previous research already showed an association between lack of friendly bacteria in an infant’s gut and the development of allergies and autoimmune diseases later in life.

But this new study discovered that when consumed early in a baby’s life through breastfeeding, B. infantis programs “naïve” immune cells away from responses related to immune-related conditions, while also producing regulatory cells that improve the body’s ability to control inflammation.

“More and more evidence is helping us understand how important the gut microbiome is in supporting the development of the immune system — and this is most critical during infancy and early life, specifically the first 100 days of life,” said Elena Ivanina, DO, a gastroenterologist at Lenox Hill Hospital in New York City.

Ivanina emphasized the importance of establishing healthy gut microbes very early in life.

“The adult microbiome is relatively stable, but a baby’s microbiome is adaptable and reflects a unique window of opportunity to influence lifelong health, including allergies, asthma, and other inflammatory diseases,” she said.

According to research published in January, the vast majority of infants born in the developed world lack this key gut microbe.

“The reduction of B. infantis in babies born in developed countries is likely the consequence of three factors: a higher frequency of cesarean delivery, use of commercial formulas instead of breast milk, and increased antibiotic use,” Ivanina said.

Dr. Bethany Henrick, PhD, director of immunology and diagnostics at Evolve BioSystems, pointed out this is the first time research has demonstrated the unique ability of B. infantis to fully break down HMOs, and that an abundance of “HMO utilization genes” in the microbiome is directly associated with decreased gut and systemic inflammation.

“This study is an exciting step forward in our understanding of the role of B. infantis EVC001 in the positive programming of immune cells and how it actually changes the trajectory of immune system development to protect against inflammation,” she said in a statement.

Ponda recommends breastfeeding if possible. But for many parents, breastfeeding is not possible or desirable.

“Speaking specifically about allergic diseases, I would encourage breastfeeding with a healthy maternal diet,” she advised.

However, Ponda sees a potential role for B. infantis supplementation, especially for infants who may not be breastfed.

“If this study leads to establishment of the benefit of supplementation with good bacteria, that may be a recommendation that parents look out for as we learn more,” Ponda said.

According to Ivanina, the safety profile of probiotics is generally good, with few side effects observed.

But use of these supplements should always be discussed with your pediatrician. They might contain cow’s milk protein, a potential allergen.

“Probiotics can be used to attempt to support the gut microbiome development of an infant and therefore prevent dysbiosis, immune dysregulation, and disease,” Ivanina said. “But these benefits cannot be guaranteed.”

According to Ivanina, this is still an area of active research, and whether health problems from B. infantis deficiency can resolve with time is “unclear.”

Asked whether parents can do anything to reduce the risk of their child developing autoimmune conditions or allergies, she offered this advice.

“Yes, parents can do their best to have healthy pregnancies and eat a healthy diet during pregnancy, encourage vaginal delivery and breastfeeding,” Ivanina said. “Attempt to avoid antibiotics unless absolutely necessary, and perhaps supplement probiotics and even prebiotics to their child if they are at risk.”

New research finds that a 100-day period after birth is critical for infants to establish a healthy gut microbiome, especially one that includes a microbe called B. infantis. This microbe thrives on certain sugars found in breast milk.

According to experts, about 90 percent of children in the developed world are deficient for B. infantis, increasing their risk of developing allergic and autoimmune disorders.

While experts emphasize breastfeeding is best for baby’s health, they also say that probiotics or prebiotics are potentially effective to help develop an infant’s gut microbiome.

Before giving any supplement to your child, talk with your pediatrician.