Disruptions to the microbiome in early life may raise the risk of certain diseases later in life.
In the journal Birth Defects Research Part C: Embryo Today, Dr. Sharon Meropol, associate director for research and evaluation at University Hospital (UH) Rainbow Babies & Children's Hospital in Cleveland, OH, and colleagues review a collection of studies in a special issue titled The Microbiome and Childhood Diseases.
The microbiome refers to the tens of trillions of microorganisms that live in our intestine, respiratory tract and on our skin.
There is increasing evidence that disruptions to a person's microbiota in early life may influence the likelihood of developing certain illnesses later in life. Earlier this year, for example, a study reported by Medical News Today found that an increase in richness of gut bacteria at 3 months of age was associated with reduced risk for food allergies at 1 year of age.
However, she points to a number of recent studies that suggest a number of factors that may aid a child's microbiome development, including breastfeeding, vaginal birth and skin-to-skin contact straight after birth.
A study reported by MNT last year, for instance, suggested that breastfeeding helps infants grow friendly gut bacteria.
Growing evidence that microbiota development begins before birth
Popular notion holds that the development of microbiota begins at birth and that the womb is a sterile environment.
However, recent studies have challenged this idea, suggesting that gut microbiota development begins before birth. Dr. Meropol and colleagues discuss this theory, pointing to a review that assesses the growing evidence that a child's microbiota development starts in the womb.
Fast facts about the gut microbiome
- The gut contains at least 1,000 species of known bacteria
- Gut micriobiota can weigh up to 2 kg
- One third of our gut microbiota is common to most people, while two thirds are specific to each person.
In a review titled "Microbial Programming of health and disease starts during fetal life," Petya T. Koleva, of the University of Alberta in Canada, and colleagues cite research that found the offspring of mothers with allergies have greater abundance of Enterobacteriaceae bacteria in their earliest stools, which may raise their risk of later-life respiratory problems.
"This means that not only do we have to consider the microbiome of the child but also that of the mother," notes Dr. Meropol, "and the irony is that some of our modern medical practices, through their effect on these early microbiota, could have unintended consequences, interfering with normal development of children's immune, metabolic, and neurologic systems."
She and her colleague Amy Edwards, also of the UH Rainbow Babies & Children's Hospital, point to formula feeding, Cesarean section, immunizations and antibiotic use as some of the modern factors that may negatively impact the early microbiome.
While there is strong existing evidence that the maternal and infant microbiomes can influence a child's disease risk, Dr. Meropol believes that the research to date has only "scratched the surface."
She and Edwards emphasize the need to "better understand these complex changes in infant developmental and molecular physiology. Protecting and repairing the developmental processes of the healthy infant microbiome is the modern medical frontier."
Earlier this month, MNT reported on a study suggesting the immune system plays a role in the evolution of gut bacteria.