A compilation of studies presented by the Henry Ford Hospital at the American Academy of Allergy, Asthma & Immunology in Houston determined that breastfeeding affects the baby’s immune system and impacts on the composition of gut bacteria.
The findings confirm the early hygiene hypothesis based on the theory that childhood exposure to microorganisms affects the immune system’s development and onset of allergies.
The researchers used six studies to evaluate whether breastfeeding and maternal and birth factors had any effect on a baby’s gut microbiome and allergic and asthma outcomes. Stool samples of infants taken at one month and six months after birth was used to investigate whether the gut microbiome impacted the development of regulatory T-cells, or Treg, which are known to regulate the immune system.
The study findings revealed the following:
• Breastfed babies at one month and six months had distinct microbiome compositions compared to non-breastfed babies. These distinct compositions may influence immune system development.
• Breastfed babies at one month were at decreased risk of developing allergies to pets.
• Asthmatic children who had nighttime coughing or flare-ups had a distinct microbiome composition during the first year of life.
• For the first time, gut microbiome composition was shown to be associated with increasing Treg cells.
Researchers found that a baby’s gut microbiome patterns vary by:
• A mother’s race/ethnicity.
• A baby’s gestational age at birth.
• Prenatal and postnatal exposure to tobacco smoke.
• Caesarean section versus vaginal delivery.
• Presence of pets in the home.
“For years now, we’ve always thought that a sterile environment was not good for babies. Our research shows why. Exposure to these microorganisms, or bacteria, in the first few months after birth actually help stimulate the immune system,” said Christine Cole Johnson, Ph.D., MPH, chair of Henry Ford’s Department of Public Health Sciences and principal research investigator. “The immune system is designed to be exposed to bacteria on a grand scale. If you minimize those exposures, the immune system won’t develop optimally.”
“The research is telling us that exposure to a higher and more diverse burden of environmental bacteria and specific patterns of gut bacteria appear to boost the immune system’s protection against allergies and asthma,” said Dr. Johnson.