Studying the link between gut bacteria and infant health
January 12, 2016
In science it sometimes helps to follow your gut. It may produce leaps of imagination and insights that lead to new understanding or scientific breakthroughs.
Dr. Anita Kozyrskyj at the University of Alberta gives new meaning to that expression as one of Canada's leading experts on the gut – the gut microbiome.
The human digestive tract is home to trillions of beneficial microbes. "Bacteria in the gut provide babies with nutrients and vitamins," says Dr. Kozyrskyj. "They also help train the immune system."
Babies get a big dose of maternal microbes during delivery. They also ingest microbes in their mother's milk and get exposed to different types of bacteria in their environment – from dust bunnies under the sofa to affectionate licks from family pets.
Dr. Kozyrskyj and her colleague Dr. James Scott at the University of Toronto lead the CIHR-funded Synergy in Microbiota Research – SyMBIOTA for short – research team. The team is studying the development of microbes in the infant gut with a focus on identifying the relationship between asthma, allergies and obesity.
Dr. Kozyrskyj and her team use data and samples collected from the Canadian Healthy Infant Longitudinal Development, or CHILD, study. Funded by CIHR and AllerGen, the CHILD study involves more than 3,500 families.
Over the past several years, the team has studied fecal samples collected from the diapers of infants in the CHILD study. The team creates profiles of these infants gut microbiota and examines the profiles in relation to information collected from the infants and their families.
What might seem like messy work has produced clear results.
Dr. Kozyrskyj and her colleagues have found that mode of delivery (cesarean section versus natural child birth) and infant nutrition (breastfeeding versus formula feeding) affects the composition and diversity of gut bacteria in babies. They have also found that infants with less diverse populations of bacteria are more likely to develop food sensitivities.
Most recently, Dr. Kozyrskyj and her team carried out a study on antibiotic use during childbirth. In a study of 198 healthy babies, they observed that 44 percent of the moms had received antibiotics to prevent infections because they were delivering by C-section or tested positive for a specific bacterium, Group B Streptococcus, which if passed on to the baby can cause serious health problems.
At three months, the babies of those moms who had received antibiotics had altered microbiomes and the changes remained at 12 months of age. Although some of the changes were modified in babies who were exclusively breastfed.
For Dr. Kozyrskyj the findings put into question the practice of routine preventive antibiotic use during child birth in Canada. Some European countries, for example, take other factors into consideration before treating a mother and her newborn with antibiotics.
"Our research shows that exposing newborns to antibiotics disrupts their gut bacteria at a critical time when they're immune system is being established," says Dr. Kozyrskyj, who was a pharmacist in a neo-natal intensive care unit before embarking on her research career.
By identifying the microbiota profile associated with asthma, allergies or other health problems, this work provides an early warning system and an opportunity for early intervention. Possible interventions include probiotic supplements, improved guidance on maternal and infant nutrition, or new standards for the use of antibiotics in child birth.
In the meantime, Dr. Kozyrskyj and her team continue to follow their research program in the drive to satisfy their intellectual curiosity or gut instinct with scientific fact.
"At the moment, we're studying the microbiota of the meconium," she says, referring to a baby's tarry black first poop. Previously thought to be sterile, recent studies have surprisingly found bacteria in samples of meconium with antibiotic resistance genes.
"We're also studying the effect of maternal weight on the microbiome of babies."
As the science rolls in, we're being given more reasons to be good to our guts.
- Canadian Healthy Infant Longitudinal Development
- AllerGen – The Allergy, Genes and Environment Network
- SyMBIOTA – Synergy in Microbiota Research
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